add el-tests vessel: manifest-based test suite under tests/suite/

Restructures the test suite as a proper El vessel with manifest.el and
src/ layout, eliminating the bash run.sh harness. CI runs the suite with
two commands: `cd tests/suite && elb && ./dist/el-tests`. Exit code is
the fail count (0 = all pass).

163 test cases across 7 modules: string (52), math (13), json (26),
state (11), time (25), fs (16), collections (19).

.gitea/workflows/ci-dev.yaml

@@ -0,0 +1,115 @@
+name: El SDK CI — dev
+
+on:
+  push:
+    branches:
+      - dev
+  pull_request:
+    branches:
+      - dev
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install build dependencies
+        run: |
+          apt-get update -qq
+          apt-get install -y gcc libcurl4-openssl-dev
+
+      # Gen2: compile the bootstrap C source into a working elc binary
+      - name: Build elc from bootstrap (gen2)
+        run: |
+          gcc -O2 \
+            -I el-compiler/runtime \
+            dist/elc-bootstrap.c \
+            el-compiler/runtime/el_runtime.c \
+            -lcurl -lpthread \
+            -o dist/elc-gen2
+          chmod +x dist/elc-gen2
+          echo "gen2 elc built"
+          dist/elc-gen2 --version || true
+
+      # Gen3: use gen2 to compile the El compiler from its own El source (self-host)
+      - name: Self-host: compile El compiler with gen2 (gen3)
+        run: |
+          mkdir -p dist/platform
+          dist/elc-gen2 el-compiler/src/compiler.el > dist/elc-gen3.c
+          gcc -O2 \
+            -I el-compiler/runtime \
+            dist/elc-gen3.c \
+            el-compiler/runtime/el_runtime.c \
+            -lcurl -lpthread \
+            -o dist/platform/elc
+          chmod +x dist/platform/elc
+          echo "gen3 (self-hosted) elc built"
+          dist/platform/elc --version || true
+
+      - name: Run tests — text
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/text/run.sh
+
+      - name: Run tests — calendar
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/calendar/run.sh
+
+      - name: Run tests — time
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/time/run.sh
+
+      - name: Run tests — html_sanitizer
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/html_sanitizer/run.sh
+
+      - name: Publish El SDK to Artifact Registry (dev)
+        env:
+          GCP_SA_KEY: ${{ secrets.GCP_SA_KEY }}
+        run: |
+          echo "${GCP_SA_KEY}" > /tmp/gcp-key.json
+          apt-get install -y -qq apt-transport-https ca-certificates gnupg curl
+          curl -fsSL https://packages.cloud.google.com/apt/doc/apt-key.gpg | gpg --dearmor -o /usr/share/keyrings/cloud.google.gpg
+          echo "deb [signed-by=/usr/share/keyrings/cloud.google.gpg] https://packages.cloud.google.com/apt cloud-sdk main" > /etc/apt/sources.list.d/google-cloud-sdk.list
+          apt-get update -qq && apt-get install -y google-cloud-cli
+          gcloud auth activate-service-account --key-file=/tmp/gcp-key.json
+          gcloud config set project neuron-785695
+
+          VERSION="${GITEA_SHA:0:8}"
+
+          gcloud artifacts generic upload \
+            --repository=foundation-dev \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/elc \
+            --version="${VERSION}" \
+            --source=dist/platform/elc
+
+          gcloud artifacts generic upload \
+            --repository=foundation-dev \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/el_runtime.c \
+            --version="${VERSION}" \
+            --source=el-compiler/runtime/el_runtime.c
+
+          gcloud artifacts generic upload \
+            --repository=foundation-dev \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/el_runtime.h \
+            --version="${VERSION}" \
+            --source=el-compiler/runtime/el_runtime.h
+
+          echo "Published El SDK version=${VERSION} to foundation-dev"
+          rm -f /tmp/gcp-key.json

.gitea/workflows/ci-stage.yaml

@@ -0,0 +1,125 @@
+name: El SDK CI — stage
+
+on:
+  push:
+    branches:
+      - stage
+  pull_request:
+    branches:
+      - stage
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Enforce source branch (stage ← dev only)
+        if: github.event_name == 'pull_request'
+        run: |
+          SOURCE="${GITHUB_HEAD_REF}"
+          if [ "${SOURCE}" != "dev" ]; then
+            echo "ERROR: Stage branch only accepts PRs from 'dev'. Source was: '${SOURCE}'"
+            exit 1
+          fi
+          echo "Source branch check passed: ${SOURCE} → stage"
+
+      - name: Install build dependencies
+        run: |
+          apt-get update -qq
+          apt-get install -y gcc libcurl4-openssl-dev
+
+      # Gen2: compile the bootstrap C source into a working elc binary
+      - name: Build elc from bootstrap (gen2)
+        run: |
+          gcc -O2 \
+            -I el-compiler/runtime \
+            dist/elc-bootstrap.c \
+            el-compiler/runtime/el_runtime.c \
+            -lcurl -lpthread \
+            -o dist/elc-gen2
+          chmod +x dist/elc-gen2
+          echo "gen2 elc built"
+          dist/elc-gen2 --version || true
+
+      # Gen3: use gen2 to compile the El compiler from its own El source (self-host)
+      - name: Self-host: compile El compiler with gen2 (gen3)
+        run: |
+          mkdir -p dist/platform
+          dist/elc-gen2 el-compiler/src/compiler.el > dist/elc-gen3.c
+          gcc -O2 \
+            -I el-compiler/runtime \
+            dist/elc-gen3.c \
+            el-compiler/runtime/el_runtime.c \
+            -lcurl -lpthread \
+            -o dist/platform/elc
+          chmod +x dist/platform/elc
+          echo "gen3 (self-hosted) elc built"
+          dist/platform/elc --version || true
+
+      - name: Run tests — text
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/text/run.sh
+
+      - name: Run tests — calendar
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/calendar/run.sh
+
+      - name: Run tests — time
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/time/run.sh
+
+      - name: Run tests — html_sanitizer
+        run: |
+          ELC="$(pwd)/dist/platform/elc" \
+          EL_HOME="$(pwd)" \
+          bash tests/html_sanitizer/run.sh
+
+      - name: Publish El SDK to Artifact Registry (stage)
+        env:
+          GCP_SA_KEY: ${{ secrets.GCP_SA_KEY }}
+        run: |
+          echo "${GCP_SA_KEY}" > /tmp/gcp-key.json
+          apt-get install -y -qq apt-transport-https ca-certificates gnupg curl
+          curl -fsSL https://packages.cloud.google.com/apt/doc/apt-key.gpg | gpg --dearmor -o /usr/share/keyrings/cloud.google.gpg
+          echo "deb [signed-by=/usr/share/keyrings/cloud.google.gpg] https://packages.cloud.google.com/apt cloud-sdk main" > /etc/apt/sources.list.d/google-cloud-sdk.list
+          apt-get update -qq && apt-get install -y google-cloud-cli
+          gcloud auth activate-service-account --key-file=/tmp/gcp-key.json
+          gcloud config set project neuron-785695
+
+          VERSION="${GITEA_SHA:0:8}"
+
+          gcloud artifacts generic upload \
+            --repository=foundation-stage \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/elc \
+            --version="${VERSION}" \
+            --source=dist/platform/elc
+
+          gcloud artifacts generic upload \
+            --repository=foundation-stage \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/el_runtime.c \
+            --version="${VERSION}" \
+            --source=el-compiler/runtime/el_runtime.c
+
+          gcloud artifacts generic upload \
+            --repository=foundation-stage \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/el_runtime.h \
+            --version="${VERSION}" \
+            --source=el-compiler/runtime/el_runtime.h
+
+          echo "Published El SDK version=${VERSION} to foundation-stage"
+          rm -f /tmp/gcp-key.json

.gitea/workflows/sdk-release.yaml

@@ -13,6 +13,16 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Enforce source branch (main ← stage only)
+        if: github.event_name == 'pull_request'
+        run: |
+          SOURCE="${GITHUB_HEAD_REF}"
+          if [ "${SOURCE}" != "stage" ]; then
+            echo "ERROR: Main branch only accepts PRs from 'stage'. Source was: '${SOURCE}'"
+            exit 1
+          fi
+          echo "Source branch check passed: ${SOURCE} → main"
+
       - name: Install build dependencies
         run: |
           apt-get update -qq
@@ -128,6 +138,48 @@ jobs:
 
           echo "Release published successfully"
 
+      # Publish artifacts to GCP Artifact Registry (prod)
+      - name: Publish El SDK to Artifact Registry (prod)
+        env:
+          GCP_SA_KEY: ${{ secrets.GCP_SA_KEY }}
+        run: |
+          echo "${GCP_SA_KEY}" > /tmp/gcp-key.json
+          apt-get install -y -qq apt-transport-https ca-certificates gnupg curl
+          curl -fsSL https://packages.cloud.google.com/apt/doc/apt-key.gpg | gpg --dearmor -o /usr/share/keyrings/cloud.google.gpg
+          echo "deb [signed-by=/usr/share/keyrings/cloud.google.gpg] https://packages.cloud.google.com/apt cloud-sdk main" > /etc/apt/sources.list.d/google-cloud-sdk.list
+          apt-get update -qq && apt-get install -y google-cloud-cli
+          gcloud auth activate-service-account --key-file=/tmp/gcp-key.json
+          gcloud config set project neuron-785695
+
+          VERSION="${GITEA_SHA:0:8}"
+
+          gcloud artifacts generic upload \
+            --repository=foundation-prod \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/elc \
+            --version="${VERSION}" \
+            --source=dist/platform/elc
+
+          gcloud artifacts generic upload \
+            --repository=foundation-prod \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/el_runtime.c \
+            --version="${VERSION}" \
+            --source=el-compiler/runtime/el_runtime.c
+
+          gcloud artifacts generic upload \
+            --repository=foundation-prod \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el/el_runtime.h \
+            --version="${VERSION}" \
+            --source=el-compiler/runtime/el_runtime.h
+
+          echo "Published El SDK version=${VERSION} to foundation-prod"
+          rm -f /tmp/gcp-key.json
+
       # Dispatch el-sdk-updated event to downstream repos
       - name: Dispatch to foundation/engram
         env:
@@ -164,3 +216,75 @@ jobs:
               }
             }"
           echo "Dispatched el-sdk-updated to neuron-technologies/forge"
+
+      - name: Dispatch to neuron-technologies/el-ui
+        env:
+          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+          GITEA_API: https://git.neuralplatform.ai/api/v1
+        run: |
+          curl -sf -X POST \
+            -H "Authorization: token ${GITEA_TOKEN}" \
+            -H "Content-Type: application/json" \
+            "${GITEA_API}/repos/neuron-technologies/el-ui/dispatches" \
+            -d "{
+              \"type\": \"el-sdk-updated\",
+              \"inputs\": {
+                \"el_version\": \"latest\",
+                \"commit\": \"${GITHUB_SHA}\"
+              }
+            }"
+          echo "Dispatched el-sdk-updated to neuron-technologies/el-ui"
+
+      - name: Dispatch to neuron-technologies/elp
+        env:
+          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+          GITEA_API: https://git.neuralplatform.ai/api/v1
+        run: |
+          curl -sf -X POST \
+            -H "Authorization: token ${GITEA_TOKEN}" \
+            -H "Content-Type: application/json" \
+            "${GITEA_API}/repos/neuron-technologies/elp/dispatches" \
+            -d "{
+              \"type\": \"el-sdk-updated\",
+              \"inputs\": {
+                \"el_version\": \"latest\",
+                \"commit\": \"${GITHUB_SHA}\"
+              }
+            }"
+          echo "Dispatched el-sdk-updated to neuron-technologies/elp"
+
+      - name: Dispatch to neuron-technologies/elql
+        env:
+          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+          GITEA_API: https://git.neuralplatform.ai/api/v1
+        run: |
+          curl -sf -X POST \
+            -H "Authorization: token ${GITEA_TOKEN}" \
+            -H "Content-Type: application/json" \
+            "${GITEA_API}/repos/neuron-technologies/elql/dispatches" \
+            -d "{
+              \"type\": \"el-sdk-updated\",
+              \"inputs\": {
+                \"el_version\": \"latest\",
+                \"commit\": \"${GITHUB_SHA}\"
+              }
+            }"
+          echo "Dispatched el-sdk-updated to neuron-technologies/elql"
+
+      - name: Dispatch to neuron-technologies/el-ide
+        env:
+          GITEA_TOKEN: ${{ secrets.GITEA_TOKEN }}
+          GITEA_API: https://git.neuralplatform.ai/api/v1
+        run: |
+          curl -sf -X POST \
+            -H "Authorization: token ${GITEA_TOKEN}" \
+            -H "Content-Type: application/json" \
+            "${GITEA_API}/repos/neuron-technologies/el-ide/dispatches" \
+            -d "{
+              \"type\": \"el-sdk-updated\",
+              \"inputs\": {
+                \"el_version\": \"latest\",
+                \"commit\": \"${GITHUB_SHA}\"
+              }
+            }"
+          echo "Dispatched el-sdk-updated to neuron-technologies/el-ide"

AGENTS.md

@@ -0,0 +1,131 @@
+# El Language — Agent Guide
+
+El is a self-hosting, statically-typed language that compiles to C. This file orients agents that work on El itself or on programs written in El.
+
+---
+
+## What El Is
+
+El compiles `.el` source → C → native binary. Every El value is `el_val_t` (int64_t). Strings are heap pointers cast through int64_t. The compiler is written in El (self-hosting).
+
+**The compiler pipeline:**
+```
+elc-cli.el
+  └─ imports: compiler.el
+       └─ imports: lexer.el, parser.el, codegen.el, codegen-js.el
+```
+
+The canonical compiler binary is `dist/platform/elc`. It was produced by running an earlier version of itself on `elc-cli.el`.
+
+---
+
+## The Two Layers — Know Which One You're In
+
+### Layer 1: El programs (`.el` files)
+
+This is where almost all work belongs. El programs are source files that get compiled by `elc`. New library functions, application logic, and language-level utilities all go here as `.el` files.
+
+**Do not add C code when El can express it.** If functionality can be built from existing El primitives (string ops, `exec`, `fs_read/write`, `http_post`, etc.), write it in El.
+
+### Layer 2: The C seed (`el-compiler/runtime/el_seed.c`)
+
+This is the self-contained C OS-boundary layer. It provides the `__`-prefixed primitives that compiled El programs call: libcurl HTTP, pthreads, filesystem I/O, arena allocation, etc. It is **not generated** — it is maintained by hand.
+
+The old `el_runtime.c` has been archived to `el-compiler/runtime/legacy/`. The runtime is now native El (`runtime/*.el`). `el_seed.c` replaces `el_runtime.c` as the sole C compilation dependency.
+
+**Only edit `el_seed.c` when you genuinely need OS-level access** (raw sockets, GPU calls, new libcurl features). For everything else, write El.
+
+When you do add a C builtin:
+1. Add the C function to `el_seed.c`
+2. Declare it in `el_seed.h`
+3. Add it to the `builtin_arity` table in `el-compiler/src/codegen.el` (so the compiler knows the arg count)
+4. Rebuild the elc binary (see below)
+
+---
+
+## Rebuilding the Compiler
+
+After changing any `.el` source in `el-compiler/src/`:
+
+```bash
+cd /Users/will/Development/neuron-technologies/foundation/el
+./dist/platform/elc elc-cli.el > elc-new.c
+cc -std=c11 -I el-compiler/runtime -lcurl -lpthread \
+   -o dist/platform/elc-new \
+   elc-new.c el-compiler/runtime/el_seed.c
+# Verify self-hosting:
+./dist/platform/elc-new elc-cli.el > elc-verify.c
+diff elc-new.c elc-verify.c   # should be identical
+mv dist/platform/elc-new dist/platform/elc
+```
+
+After changing `el_seed.c` only (no El source changes), rebuild downstream programs but do NOT need to rebuild the compiler binary itself — the seed is linked at the application level, not the compiler level.
+
+---
+
+## How El Programs Are Built
+
+Each El application has a `build.sh` that:
+1. Concatenates all `.el` source files (stripping `import` lines)
+2. Runs `elc` to produce a `.c` file
+3. Runs `cc` linking against `el_seed.c`
+
+Example (cgi-studio daemon):
+```bash
+cd products/cgi-studio/el-daemon
+./build.sh
+```
+
+When you add a new `.el` file to an application, add it to that application's `build.sh` concat list.
+
+---
+
+## Parallelism in El
+
+El is single-threaded at the application level. Parallelism is achieved through subprocess fan-out:
+
+```el
+// Pattern: write payloads to temp files, exec bash script with & and wait,
+// read results back from temp files.
+fn http_post_parallel(urls: [String], bodies: [String]) -> [String] {
+    // ... bash fan-out via exec() ...
+}
+```
+
+Use `exec()` (blocking) or `exec_bg()` (fire-and-forget) with shell scripts to run concurrent work. There is no goroutine or async/await — parallelism goes through the OS process layer.
+
+---
+
+## Key Files
+
+| Path | What it is |
+|------|-----------|
+| `dist/platform/elc` | Canonical compiler binary (arm64 Mac) |
+| `el-compiler/src/codegen.el` | Code generator — builtin arity table lives here |
+| `el-compiler/src/lexer.el` | Lexer |
+| `el-compiler/src/parser.el` | Parser |
+| `el-compiler/runtime/el_seed.c` | Self-contained C OS-boundary layer (replaces el_runtime.c) |
+| `el-compiler/runtime/el_seed.h` | Seed header (C function declarations) |
+| `spec/language.md` | Language specification |
+| `BOOTSTRAP.md` | How to recover the compiler from scratch |
+| `elc-cli.el` | Compiler entry point |
+| `elc-combined.el` | Pre-merged single-file compiler (used during early bootstrap) |
+
+---
+
+## HTTP Timeout
+
+The El HTTP client (libcurl) defaults to **60 seconds**. Override per-process via `EL_HTTP_TIMEOUT_MS` env var. Set it before spawning any subprocess that makes long API calls:
+
+```el
+exec("EL_HTTP_TIMEOUT_MS=300000 " + SOME_BIN + " " + args + " 2>&1")
+```
+
+---
+
+## Rules
+
+- New library functions → write in El
+- New OS/hardware primitives → write in C and register in `codegen.el` arity table
+- Never edit `dist/platform/elc` directly — always rebuild from source
+- Never modify `el_seed.c` to add functionality that El can express

el-compiler/runtime/el_runtime.c

@@ -38,6 +38,7 @@
 #include <arpa/inet.h>
 #include <dlfcn.h>      /* dlsym for http_set_handler fallback */
 #include <unistd.h>
+#include <fcntl.h>
 #include <dirent.h>
 #include <errno.h>
 #include <pthread.h>
@@ -154,6 +155,39 @@ el_val_t readline(void) {
     return el_wrap_str(el_strdup(buf));
 }
 
+/* __read_n — read exactly n bytes from stdin.
+ * Allocates a buffer of size n+1, calls fread(buf, 1, n, stdin) to read
+ * exactly n raw bytes (including \r, \n, NUL, etc.), null-terminates, and
+ * returns the buffer as an El String.  Returns "" on EOF or I/O error.
+ *
+ * Used by the El LSP server to read JSON-RPC message bodies after parsing
+ * the Content-Length header.  readline() cannot be used for the body because
+ * it stops at the first \n and LSP JSON bodies are not newline-terminated.  */
+el_val_t __read_n(el_val_t nv) {
+    int64_t n = EL_INT(nv);
+    if (n <= 0) return el_wrap_str(el_strdup(""));
+    char* buf = malloc((size_t)n + 1);
+    if (!buf) { fputs("el_runtime: __read_n: out of memory\n", stderr); return el_wrap_str(el_strdup("")); }
+    size_t got = fread(buf, 1, (size_t)n, stdin);
+    buf[got] = '\0';
+    if (got == 0) { free(buf); return el_wrap_str(el_strdup("")); }
+    /* Track in arena so the allocation is freed when the request ends. */
+    el_arena_track(buf);
+    return el_wrap_str(buf);
+}
+
+/* __print_raw — write a string to stdout without any modification.
+ * Unlike println/print (which call puts/fputs and may add newlines or flush
+ * in platform-specific ways), this uses fwrite with the exact byte count so
+ * that embedded \r\n pairs in LSP Content-Length headers survive intact.    */
+void __print_raw(el_val_t sv) {
+    const char* s = EL_CSTR(sv);
+    if (!s) return;
+    size_t len = strlen(s);
+    fwrite(s, 1, len, stdout);
+    fflush(stdout);
+}
+
 /* ── String builtins ─────────────────────────────────────────────────────── */
 
 el_val_t el_str_concat(el_val_t av, el_val_t bv) {
@@ -1876,6 +1910,61 @@ el_val_t exec_capture(el_val_t cmdv) {
     return el_wrap_str(b.buf);
 }
 
+// exec — run a shell command via /bin/sh, capture stdout, return as String.
+// Times out after 30 seconds. Returns "" on any error.
+// El name: exec(cmd) -> String
+el_val_t exec(el_val_t cmdv) {
+    const char* cmd = EL_CSTR(cmdv);
+    if (!cmd || !*cmd) return el_wrap_str(el_strdup(""));
+    /* Build a time-limited command: wrap with timeout(1) if available,
+     * otherwise rely on the 30s read loop guard below. We use the simple
+     * popen approach with a deadline measured by wall clock so the caller
+     * is never blocked indefinitely. */
+    FILE* f = popen(cmd, "r");
+    if (!f) return el_wrap_str(el_strdup(""));
+    JsonBuf b; jb_init(&b);
+    char buf[4096];
+    /* 30-second wall-clock deadline */
+    time_t deadline = time(NULL) + 30;
+    while (time(NULL) < deadline) {
+        if (fgets(buf, sizeof(buf), f) == NULL) break;
+        jb_puts(&b, buf);
+    }
+    pclose(f);
+    return el_wrap_str(b.buf);
+}
+
+// exec_bg — run a shell command in background, return PID as String.
+// The child process runs independently; the caller is not blocked.
+// Returns "" on fork failure.
+// El name: exec_bg(cmd) -> String
+el_val_t exec_bg(el_val_t cmdv) {
+    const char* cmd = EL_CSTR(cmdv);
+    if (!cmd || !*cmd) return el_wrap_str(el_strdup(""));
+    pid_t pid = fork();
+    if (pid < 0) {
+        /* fork failed */
+        return el_wrap_str(el_strdup(""));
+    }
+    if (pid == 0) {
+        /* child: detach from parent's stdio, exec via shell */
+        setsid();
+        int devnull = open("/dev/null", O_RDWR);
+        if (devnull >= 0) {
+            dup2(devnull, STDIN_FILENO);
+            dup2(devnull, STDOUT_FILENO);
+            dup2(devnull, STDERR_FILENO);
+            close(devnull);
+        }
+        execl("/bin/sh", "sh", "-c", cmd, (char*)NULL);
+        _exit(127);
+    }
+    /* parent: convert pid to string and return immediately */
+    char pidbuf[32];
+    snprintf(pidbuf, sizeof(pidbuf), "%d", (int)pid);
+    return el_wrap_str(el_strdup(pidbuf));
+}
+
 el_val_t fs_list(el_val_t pathv) {
     const char* path = EL_CSTR(pathv);
     el_val_t lst = el_list_empty();
@@ -10188,3 +10277,650 @@ el_val_t emit_event(el_val_t name_v, el_val_t duration_ms_v) {
     return trace_span_end(h);
 }
 
+/* ── Threading seed primitives ───────────────────────────────────────────────
+ * __thread_create(fn_name, arg) -> Int   spawn El fn in a pthread, return tid
+ * __thread_join(tid)            -> String join thread, return result string
+ * __mutex_new()                 -> Int    allocate a mutex, return handle
+ * __mutex_lock(m)                         lock mutex m
+ * __mutex_unlock(m)                       unlock mutex m
+ *
+ * Every El fn compiles to a global C symbol. __thread_create uses dlsym to
+ * look up the function by name and run it in a pthread. This means any El fn
+ * with signature (String) -> String is directly threadable.
+ */
+
+typedef el_val_t (*ElFn1)(el_val_t);
+
+typedef struct {
+    ElFn1     fn;
+    el_val_t  arg;
+    el_val_t  result;
+} ElThreadArg;
+
+#define EL_THREAD_MAX 256
+
+typedef struct {
+    pthread_t     tid;
+    ElThreadArg*  arg;
+    int           alive;
+} ElThread;
+
+static ElThread        _threads[EL_THREAD_MAX];
+static int             _thread_count = 0;
+static pthread_mutex_t _thread_alloc_mu = PTHREAD_MUTEX_INITIALIZER;
+
+static void* el_thread_runner(void* raw) {
+    ElThreadArg* a = (ElThreadArg*)raw;
+    a->result = a->fn(a->arg);
+    return NULL;
+}
+
+el_val_t __thread_create(el_val_t fn_name_v, el_val_t arg_v) {
+    const char* sym = EL_CSTR(fn_name_v);
+    if (!sym || !*sym) return EL_INT(-1);
+    void* p = dlsym(RTLD_DEFAULT, sym);
+    if (!p) {
+        fprintf(stderr, "[__thread_create] symbol not found: %s\n", sym);
+        return EL_INT(-1);
+    }
+    ElThreadArg* a = (ElThreadArg*)malloc(sizeof(ElThreadArg));
+    if (!a) return EL_INT(-1);
+    a->fn     = (ElFn1)p;
+    a->arg    = arg_v;
+    a->result = EL_STR("");
+
+    pthread_mutex_lock(&_thread_alloc_mu);
+    if (_thread_count >= EL_THREAD_MAX) {
+        pthread_mutex_unlock(&_thread_alloc_mu);
+        free(a);
+        fprintf(stderr, "[__thread_create] thread table full\n");
+        return EL_INT(-1);
+    }
+    int slot = _thread_count++;
+    _threads[slot].arg   = a;
+    _threads[slot].alive = 1;
+    pthread_mutex_unlock(&_thread_alloc_mu);
+
+    if (pthread_create(&_threads[slot].tid, NULL, el_thread_runner, a) != 0) {
+        pthread_mutex_lock(&_thread_alloc_mu);
+        _thread_count--;
+        pthread_mutex_unlock(&_thread_alloc_mu);
+        free(a);
+        return EL_INT(-1);
+    }
+    return EL_INT(slot);
+}
+
+el_val_t __thread_join(el_val_t tid_v) {
+    int slot = (int)(int64_t)tid_v;
+    if (slot < 0 || slot >= EL_THREAD_MAX) return EL_STR("");
+    pthread_join(_threads[slot].tid, NULL);
+    el_val_t result = _threads[slot].arg->result;
+    free(_threads[slot].arg);
+    _threads[slot].alive = 0;
+    return result;
+}
+
+/* Mutex table */
+
+#define EL_MUTEX_MAX 64
+
+typedef struct {
+    pthread_mutex_t mu;
+    int             allocated;
+} ElMutexEntry;
+
+static ElMutexEntry    _mutexes[EL_MUTEX_MAX];
+static int             _mutex_count = 0;
+static pthread_mutex_t _mutex_alloc_mu = PTHREAD_MUTEX_INITIALIZER;
+
+el_val_t __mutex_new(void) {
+    pthread_mutex_lock(&_mutex_alloc_mu);
+    if (_mutex_count >= EL_MUTEX_MAX) {
+        pthread_mutex_unlock(&_mutex_alloc_mu);
+        fprintf(stderr, "[__mutex_new] mutex table full\n");
+        return EL_INT(-1);
+    }
+    int slot = _mutex_count++;
+    pthread_mutex_init(&_mutexes[slot].mu, NULL);
+    _mutexes[slot].allocated = 1;
+    pthread_mutex_unlock(&_mutex_alloc_mu);
+    return EL_INT(slot);
+}
+
+void __mutex_lock(el_val_t m_v) {
+    int slot = (int)(int64_t)m_v;
+    if (slot < 0 || slot >= EL_MUTEX_MAX || !_mutexes[slot].allocated) return;
+    pthread_mutex_lock(&_mutexes[slot].mu);
+}
+
+void __mutex_unlock(el_val_t m_v) {
+    int slot = (int)(int64_t)m_v;
+    if (slot < 0 || slot >= EL_MUTEX_MAX || !_mutexes[slot].allocated) return;
+    pthread_mutex_unlock(&_mutexes[slot].mu);
+}
+
+/* ── Channels ─────────────────────────────────────────────────────────────── *
+ * Buffered MPMC channel backed by a mutex + condvar + circular buffer.
+ * channel_new(capacity) -> Int (handle)
+ * channel_send(ch, msg)         — blocks if full (capacity > 0) or never (unbounded)
+ * channel_recv(ch) -> String    — blocks until a message is available
+ * channel_try_recv(ch) -> String — non-blocking, returns "" if empty
+ * channel_close(ch)             — signal no more sends; recv drains remaining
+ *
+ * Bounded channels (cap > 0): circular buffer, sender blocks when full.
+ * Unbounded channels (cap == 0): dynamic array, sender never blocks.
+ */
+#define EL_CHANNEL_MAX 64
+#define EL_CHANNEL_BUF 1024
+
+typedef struct {
+    char**          buf;
+    int             cap;     /* 0 = unbounded (grows dynamically) */
+    int             head, tail, count;
+    int             dyn_cap; /* allocated slots for unbounded mode */
+    int             closed;
+    pthread_mutex_t mu;
+    pthread_cond_t  not_empty;
+    pthread_cond_t  not_full;
+} ElChannel;
+
+static ElChannel       _channels[EL_CHANNEL_MAX];
+static int             _channel_count = 0;
+static pthread_mutex_t _channel_alloc_mu = PTHREAD_MUTEX_INITIALIZER;
+
+el_val_t __channel_new(el_val_t capacity_v) {
+    int cap = (int)(int64_t)capacity_v;
+    if (cap < 0) cap = 0;
+
+    pthread_mutex_lock(&_channel_alloc_mu);
+    if (_channel_count >= EL_CHANNEL_MAX) {
+        pthread_mutex_unlock(&_channel_alloc_mu);
+        fprintf(stderr, "[__channel_new] channel table full\n");
+        return EL_INT(-1);
+    }
+    int slot = _channel_count++;
+    pthread_mutex_unlock(&_channel_alloc_mu);
+
+    ElChannel* ch = &_channels[slot];
+    memset(ch, 0, sizeof(*ch));
+    ch->cap     = cap;
+    ch->closed  = 0;
+    ch->head    = 0;
+    ch->tail    = 0;
+    ch->count   = 0;
+
+    if (cap > 0) {
+        /* Bounded: fixed circular buffer. */
+        ch->buf     = (char**)malloc((size_t)cap * sizeof(char*));
+        ch->dyn_cap = cap;
+    } else {
+        /* Unbounded: start with EL_CHANNEL_BUF slots, grow as needed. */
+        ch->buf     = (char**)malloc(EL_CHANNEL_BUF * sizeof(char*));
+        ch->dyn_cap = EL_CHANNEL_BUF;
+    }
+    if (!ch->buf) {
+        fprintf(stderr, "[__channel_new] out of memory\n");
+        return EL_INT(-1);
+    }
+
+    pthread_mutex_init(&ch->mu, NULL);
+    pthread_cond_init(&ch->not_empty, NULL);
+    pthread_cond_init(&ch->not_full, NULL);
+
+    return EL_INT(slot);
+}
+
+void __channel_send(el_val_t ch_v, el_val_t msg_v) {
+    int slot = (int)(int64_t)ch_v;
+    if (slot < 0 || slot >= EL_CHANNEL_MAX) return;
+    ElChannel* ch = &_channels[slot];
+
+    const char* msg = EL_CSTR(msg_v);
+    if (!msg) msg = "";
+    char* copy = strdup(msg); /* channel owns the string */
+
+    pthread_mutex_lock(&ch->mu);
+
+    if (ch->closed) {
+        /* Send on closed channel is a no-op (drop the message). */
+        pthread_mutex_unlock(&ch->mu);
+        free(copy);
+        return;
+    }
+
+    if (ch->cap > 0) {
+        /* Bounded: block while full. */
+        while (ch->count >= ch->cap && !ch->closed) {
+            pthread_cond_wait(&ch->not_full, &ch->mu);
+        }
+        if (ch->closed) {
+            pthread_mutex_unlock(&ch->mu);
+            free(copy);
+            return;
+        }
+        ch->buf[ch->tail] = copy;
+        ch->tail = (ch->tail + 1) % ch->cap;
+        ch->count++;
+    } else {
+        /* Unbounded: grow the buffer if needed. */
+        if (ch->count >= ch->dyn_cap) {
+            int new_cap = ch->dyn_cap * 2;
+            char** grown = (char**)realloc(ch->buf, (size_t)new_cap * sizeof(char*));
+            if (!grown) {
+                pthread_mutex_unlock(&ch->mu);
+                free(copy);
+                fprintf(stderr, "[__channel_send] out of memory growing channel\n");
+                return;
+            }
+            /* The circular buffer may have wrapped. Linearise it first.
+             * In unbounded mode head is always 0 (we append at tail, drain
+             * from head), so a simple memmove isn't needed — but if the
+             * buffer did wrap (tail < head after growth), we need to fix up.
+             * Simplest safe path: if tail wrapped, move the head..old_cap
+             * segment to new_cap..new_cap+(old_cap-head). */
+            if (ch->tail < ch->head) {
+                /* Wrapped: [head..old_cap) is the front, [0..tail) is the back. */
+                int front = ch->dyn_cap - ch->head;
+                memmove(grown + ch->dyn_cap, grown + ch->head, (size_t)front * sizeof(char*));
+                ch->head = ch->dyn_cap;
+            }
+            ch->buf     = grown;
+            ch->dyn_cap = new_cap;
+        }
+        ch->buf[ch->tail] = copy;
+        ch->tail = (ch->tail + 1) % ch->dyn_cap;
+        ch->count++;
+    }
+
+    pthread_cond_signal(&ch->not_empty);
+    pthread_mutex_unlock(&ch->mu);
+}
+
+el_val_t __channel_recv(el_val_t ch_v) {
+    int slot = (int)(int64_t)ch_v;
+    if (slot < 0 || slot >= EL_CHANNEL_MAX) return EL_STR("");
+    ElChannel* ch = &_channels[slot];
+
+    pthread_mutex_lock(&ch->mu);
+
+    /* Block until there is a message or the channel is closed and drained. */
+    while (ch->count == 0 && !ch->closed) {
+        pthread_cond_wait(&ch->not_empty, &ch->mu);
+    }
+
+    if (ch->count == 0) {
+        /* Closed and empty — signal EOF. */
+        pthread_mutex_unlock(&ch->mu);
+        return EL_STR("");
+    }
+
+    int buf_cap = (ch->cap > 0) ? ch->cap : ch->dyn_cap;
+    char* msg = ch->buf[ch->head];
+    ch->head  = (ch->head + 1) % buf_cap;
+    ch->count--;
+
+    pthread_cond_signal(&ch->not_full);
+    pthread_mutex_unlock(&ch->mu);
+
+    /* Hand the string to the arena so it is freed after the request. */
+    el_arena_track(msg);
+    return EL_STR(msg);
+}
+
+el_val_t __channel_try_recv(el_val_t ch_v) {
+    int slot = (int)(int64_t)ch_v;
+    if (slot < 0 || slot >= EL_CHANNEL_MAX) return EL_STR("");
+    ElChannel* ch = &_channels[slot];
+
+    pthread_mutex_lock(&ch->mu);
+
+    if (ch->count == 0) {
+        pthread_mutex_unlock(&ch->mu);
+        return EL_STR("");
+    }
+
+    int buf_cap = (ch->cap > 0) ? ch->cap : ch->dyn_cap;
+    char* msg = ch->buf[ch->head];
+    ch->head  = (ch->head + 1) % buf_cap;
+    ch->count--;
+
+    pthread_cond_signal(&ch->not_full);
+    pthread_mutex_unlock(&ch->mu);
+
+    el_arena_track(msg);
+    return EL_STR(msg);
+}
+
+void __channel_close(el_val_t ch_v) {
+    int slot = (int)(int64_t)ch_v;
+    if (slot < 0 || slot >= EL_CHANNEL_MAX) return;
+    ElChannel* ch = &_channels[slot];
+
+    pthread_mutex_lock(&ch->mu);
+    ch->closed = 1;
+    /* Wake all blocked recvers and senders so they can observe the close. */
+    pthread_cond_broadcast(&ch->not_empty);
+    pthread_cond_broadcast(&ch->not_full);
+    pthread_mutex_unlock(&ch->mu);
+}
+
+/* ── DHARMA runtime additions ────────────────────────────────────────────────
+ *
+ * Functions required by the dharma registry service. Added here so the
+ * released el_runtime.c includes them without requiring dharma to bundle
+ * its own stubs.
+ *
+ * Functions added:
+ *   list_len          — alias for el_list_len (used in handlers.el)
+ *   list_get          — alias for el_list_get  (used in handlers.el)
+ *   json_array_push   — append a pre-encoded JSON element to a JSON array string
+ *   now_millis        — milliseconds since Unix epoch (alias for time_now)
+ *   unix_timestamp_ms — same as now_millis (alias)
+ *   time_now_ms       — same as now_millis (alias)
+ *   log_info          — stderr structured log at INFO level
+ *   log_warn          — stderr structured log at WARN level
+ *   config            — reads a config value from the environment
+ *   http_patch        — HTTP PATCH with JSON Content-Type
+ *   http_post_engram  — HTTP POST with optional X-API-Key header
+ *   http_get_engram   — HTTP GET  with optional X-API-Key header
+ *   str_to_bytes      — encode a string as a JSON array of byte values
+ *   bytes_to_str      — decode a JSON array of byte values back to a string
+ *   hash_sha256       — SHA-256 hex digest of a string
+ */
+
+/* list_len — return the number of elements in a list. */
+el_val_t list_len(el_val_t list) {
+    return el_list_len(list);
+}
+
+/* list_get — return the element at index i in a list. */
+el_val_t list_get(el_val_t list, el_val_t index) {
+    return el_list_get(list, index);
+}
+
+/* json_array_push — append element (a pre-encoded JSON fragment, e.g. "\"foo\""
+ * or "42") to the JSON array string arr. Returns a new JSON array string.
+ * Example: json_array_push("[]", "\"alice\"") -> "[\"alice\"]"
+ *          json_array_push("[\"alice\"]", "\"bob\"") -> "[\"alice\",\"bob\"]" */
+el_val_t json_array_push(el_val_t arr_v, el_val_t elem_v) {
+    const char* arr  = EL_CSTR(arr_v);
+    const char* elem = EL_CSTR(elem_v);
+    if (!arr  || !*arr)  arr  = "[]";
+    if (!elem || !*elem) elem = "null";
+
+    /* Trim whitespace, find the closing ']'. */
+    const char* p = arr;
+    while (*p == ' ' || *p == '\t' || *p == '\n' || *p == '\r') p++;
+    if (*p != '[') {
+        /* Not an array — return a single-element array. */
+        size_t n = strlen(elem) + 4;
+        char* out = el_strbuf(n);
+        snprintf(out, n, "[%s]", elem);
+        return el_wrap_str(out);
+    }
+    size_t arr_len  = strlen(arr);
+    size_t elem_len = strlen(elem);
+
+    /* Walk from the end to find the matching ']'. */
+    const char* end = arr + arr_len - 1;
+    while (end > p && (*end == ' ' || *end == '\t' || *end == '\n' || *end == '\r')) end--;
+    if (*end != ']') {
+        /* Malformed — wrap elem in a new array. */
+        size_t n = elem_len + 4;
+        char* out = el_strbuf(n);
+        snprintf(out, n, "[%s]", elem);
+        return el_wrap_str(out);
+    }
+
+    /* Content between '[' and ']'. */
+    const char* inner_start = p + 1;
+    const char* inner_end   = end;       /* points AT ']' */
+    /* Check if the array is empty (only whitespace between brackets). */
+    const char* q = inner_start;
+    while (q < inner_end && (*q == ' ' || *q == '\t' || *q == '\n' || *q == '\r')) q++;
+    int empty = (q == inner_end);
+
+    /* Build: prefix + (comma if non-empty) + elem + "]" */
+    size_t prefix_len = (size_t)(inner_end - arr); /* up to but not including ']' */
+    size_t sep_len    = empty ? 0 : 1;              /* "," if non-empty */
+    size_t out_len    = prefix_len + sep_len + elem_len + 2; /* +"]" + NUL */
+    char* out = el_strbuf(out_len);
+    memcpy(out, arr, prefix_len);
+    if (!empty) out[prefix_len] = ',';
+    memcpy(out + prefix_len + sep_len, elem, elem_len);
+    out[prefix_len + sep_len + elem_len] = ']';
+    out[prefix_len + sep_len + elem_len + 1] = '\0';
+    return el_wrap_str(out);
+}
+
+/* now_millis — milliseconds since Unix epoch. */
+el_val_t now_millis(void) {
+    return time_now();
+}
+
+/* unix_timestamp_ms — same as now_millis. */
+el_val_t unix_timestamp_ms(void) {
+    return time_now();
+}
+
+/* time_now_ms — same as now_millis. */
+el_val_t time_now_ms(void) {
+    return time_now();
+}
+
+/* log_info — write a structured [INFO] line to stderr. */
+void log_info(el_val_t msg_v) {
+    const char* msg = EL_CSTR(msg_v);
+    fprintf(stderr, "[INFO] %s\n", msg ? msg : "");
+}
+
+/* log_warn — write a structured [WARN] line to stderr. */
+void log_warn(el_val_t msg_v) {
+    const char* msg = EL_CSTR(msg_v);
+    fprintf(stderr, "[WARN] %s\n", msg ? msg : "");
+}
+
+/* config — read a configuration value from the environment.
+ * Returns "" if the variable is not set (same as __env_get). */
+el_val_t config(el_val_t key_v) {
+    const char* key = EL_CSTR(key_v);
+    if (!key || !*key) return EL_STR("");
+    const char* val = getenv(key);
+    if (!val) return EL_STR("");
+    return el_wrap_str(el_strdup(val));
+}
+
+/* http_patch — HTTP PATCH request with Content-Type: application/json.
+ * Returns the response body (same error convention as http_post_json). */
+el_val_t http_patch(el_val_t url_v, el_val_t body_v) {
+    const char* url  = EL_CSTR(url_v);
+    const char* body = EL_CSTR(body_v);
+    if (!url || !*url) return http_error_json("empty url");
+    CURL* c = curl_easy_init();
+    if (!c) return http_error_json("curl_easy_init failed");
+    HttpBuf rb; httpbuf_init(&rb);
+    char errbuf[CURL_ERROR_SIZE]; errbuf[0] = '\0';
+    struct curl_slist* h = NULL;
+    h = curl_slist_append(h, "Content-Type: application/json");
+    curl_easy_setopt(c, CURLOPT_URL, url);
+    curl_easy_setopt(c, CURLOPT_CUSTOMREQUEST, "PATCH");
+    curl_easy_setopt(c, CURLOPT_POSTFIELDS, body ? body : "");
+    curl_easy_setopt(c, CURLOPT_POSTFIELDSIZE, (long)(body ? strlen(body) : 0));
+    curl_easy_setopt(c, CURLOPT_HTTPHEADER, h);
+    curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, http_write_cb);
+    curl_easy_setopt(c, CURLOPT_WRITEDATA, &rb);
+    curl_easy_setopt(c, CURLOPT_FOLLOWLOCATION, 1L);
+    curl_easy_setopt(c, CURLOPT_TIMEOUT_MS, el_http_timeout_ms());
+    curl_easy_setopt(c, CURLOPT_NOSIGNAL, 1L);
+    curl_easy_setopt(c, CURLOPT_ERRORBUFFER, errbuf);
+    curl_easy_setopt(c, CURLOPT_USERAGENT, "el-runtime/1.0");
+    CURLcode rc = curl_easy_perform(c);
+    curl_slist_free_all(h);
+    curl_easy_cleanup(c);
+    if (rc != CURLE_OK) {
+        free(rb.data);
+        const char* m = errbuf[0] ? errbuf : curl_easy_strerror(rc);
+        return http_error_json(m);
+    }
+    return el_wrap_str(rb.data);
+}
+
+/* http_post_engram — HTTP POST with optional X-API-Key header.
+ * If key is "" no authentication header is sent. */
+el_val_t http_post_engram(el_val_t url_v, el_val_t key_v, el_val_t body_v) {
+    const char* url  = EL_CSTR(url_v);
+    const char* key  = EL_CSTR(key_v);
+    const char* body = EL_CSTR(body_v);
+    if (!url || !*url) return http_error_json("empty url");
+    CURL* c = curl_easy_init();
+    if (!c) return http_error_json("curl_easy_init failed");
+    HttpBuf rb; httpbuf_init(&rb);
+    char errbuf[CURL_ERROR_SIZE]; errbuf[0] = '\0';
+    struct curl_slist* h = NULL;
+    h = curl_slist_append(h, "Content-Type: application/json");
+    if (key && *key) {
+        size_t n = strlen(key) + 32;
+        char* hdr = malloc(n);
+        snprintf(hdr, n, "X-API-Key: %s", key);
+        h = curl_slist_append(h, hdr);
+        free(hdr);
+    }
+    curl_easy_setopt(c, CURLOPT_URL, url);
+    curl_easy_setopt(c, CURLOPT_POST, 1L);
+    curl_easy_setopt(c, CURLOPT_POSTFIELDS, body ? body : "");
+    curl_easy_setopt(c, CURLOPT_POSTFIELDSIZE, (long)(body ? strlen(body) : 0));
+    curl_easy_setopt(c, CURLOPT_HTTPHEADER, h);
+    curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, http_write_cb);
+    curl_easy_setopt(c, CURLOPT_WRITEDATA, &rb);
+    curl_easy_setopt(c, CURLOPT_FOLLOWLOCATION, 1L);
+    curl_easy_setopt(c, CURLOPT_TIMEOUT_MS, el_http_timeout_ms());
+    curl_easy_setopt(c, CURLOPT_NOSIGNAL, 1L);
+    curl_easy_setopt(c, CURLOPT_ERRORBUFFER, errbuf);
+    curl_easy_setopt(c, CURLOPT_USERAGENT, "el-runtime/1.0");
+    CURLcode rc = curl_easy_perform(c);
+    curl_slist_free_all(h);
+    curl_easy_cleanup(c);
+    if (rc != CURLE_OK) {
+        free(rb.data);
+        const char* m = errbuf[0] ? errbuf : curl_easy_strerror(rc);
+        return http_error_json(m);
+    }
+    return el_wrap_str(rb.data);
+}
+
+/* http_get_engram — HTTP GET with optional X-API-Key header. */
+el_val_t http_get_engram(el_val_t url_v, el_val_t key_v) {
+    const char* url = EL_CSTR(url_v);
+    const char* key = EL_CSTR(key_v);
+    if (!url || !*url) return http_error_json("empty url");
+    CURL* c = curl_easy_init();
+    if (!c) return http_error_json("curl_easy_init failed");
+    HttpBuf rb; httpbuf_init(&rb);
+    char errbuf[CURL_ERROR_SIZE]; errbuf[0] = '\0';
+    struct curl_slist* h = NULL;
+    if (key && *key) {
+        size_t n = strlen(key) + 32;
+        char* hdr = malloc(n);
+        snprintf(hdr, n, "X-API-Key: %s", key);
+        h = curl_slist_append(h, hdr);
+        free(hdr);
+    }
+    curl_easy_setopt(c, CURLOPT_URL, url);
+    curl_easy_setopt(c, CURLOPT_HTTPGET, 1L);
+    if (h) curl_easy_setopt(c, CURLOPT_HTTPHEADER, h);
+    curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, http_write_cb);
+    curl_easy_setopt(c, CURLOPT_WRITEDATA, &rb);
+    curl_easy_setopt(c, CURLOPT_FOLLOWLOCATION, 1L);
+    curl_easy_setopt(c, CURLOPT_TIMEOUT_MS, el_http_timeout_ms());
+    curl_easy_setopt(c, CURLOPT_NOSIGNAL, 1L);
+    curl_easy_setopt(c, CURLOPT_ERRORBUFFER, errbuf);
+    curl_easy_setopt(c, CURLOPT_USERAGENT, "el-runtime/1.0");
+    CURLcode rc = curl_easy_perform(c);
+    if (h) curl_slist_free_all(h);
+    curl_easy_cleanup(c);
+    if (rc != CURLE_OK) {
+        free(rb.data);
+        const char* m = errbuf[0] ? errbuf : curl_easy_strerror(rc);
+        return http_error_json(m);
+    }
+    return el_wrap_str(rb.data);
+}
+
+/* str_to_bytes — encode a string as a JSON array of unsigned byte values.
+ * "hello" -> "[104,101,108,108,111]"
+ * Used by db.el to store binary content in Engram JSON nodes. */
+el_val_t str_to_bytes(el_val_t sv) {
+    const char* s = EL_CSTR(sv);
+    if (!s || !*s) return el_wrap_str(el_strdup("[]"));
+    size_t n = strlen(s);
+    /* Worst case: each byte is 3 digits + comma = 4 chars, plus "[]" + NUL. */
+    char* out = el_strbuf(n * 4 + 3);
+    size_t pos = 0;
+    out[pos++] = '[';
+    for (size_t i = 0; i < n; i++) {
+        unsigned char b = (unsigned char)s[i];
+        if (i > 0) out[pos++] = ',';
+        /* Write decimal representation of b. */
+        if (b >= 100) {
+            out[pos++] = (char)('0' + b / 100);
+            out[pos++] = (char)('0' + (b / 10) % 10);
+            out[pos++] = (char)('0' + b % 10);
+        } else if (b >= 10) {
+            out[pos++] = (char)('0' + b / 10);
+            out[pos++] = (char)('0' + b % 10);
+        } else {
+            out[pos++] = (char)('0' + b);
+        }
+    }
+    out[pos++] = ']';
+    out[pos] = '\0';
+    return el_wrap_str(out);
+}
+
+/* bytes_to_str — decode a JSON array of integer byte values back to a string.
+ * "[104,101,108,108,111]" -> "hello"
+ * Inverse of str_to_bytes. */
+el_val_t bytes_to_str(el_val_t arr_v) {
+    const char* s = EL_CSTR(arr_v);
+    if (!s) return el_wrap_str(el_strdup(""));
+    /* Skip whitespace, expect '['. */
+    while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r') s++;
+    if (*s != '[') return el_wrap_str(el_strdup(""));
+    s++;
+
+    /* Count elements to size the output buffer. */
+    int64_t n = (int64_t)json_array_len(arr_v);
+    if (n <= 0) return el_wrap_str(el_strdup(""));
+
+    char* out = el_strbuf((size_t)n + 1);
+    size_t pos = 0;
+
+    /* Walk the array, parse each integer, store as a byte. */
+    while (*s) {
+        while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r') s++;
+        if (*s == ']' || *s == '\0') break;
+        /* Parse decimal integer. */
+        char* end_ptr;
+        long v = strtol(s, &end_ptr, 10);
+        if (end_ptr == s) break; /* parse failure */
+        s = end_ptr;
+        if (v >= 0 && v <= 255) out[pos++] = (char)(unsigned char)v;
+        while (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r') s++;
+        if (*s == ',') { s++; continue; }
+        if (*s == ']' || *s == '\0') break;
+    }
+    out[pos] = '\0';
+    return el_wrap_str(out);
+}
+
+/* hash_sha256 — return the SHA-256 hex digest of a string.
+ * Uses the built-in el_sha256_oneshot implementation (no OpenSSL required). */
+el_val_t hash_sha256(el_val_t sv) {
+    const char* s = EL_CSTR(sv);
+    if (!s) s = "";
+    unsigned char digest[32];
+    el_sha256_oneshot((const unsigned char*)s, strlen(s), digest);
+    return el_hex_encode(digest, 32);
+}
+

el-compiler/runtime/el_runtime.h

@@ -176,6 +176,11 @@ void      http_set_handler_v2(el_val_t name);
  * auto-content-type contract for legacy handlers that return plain bodies. */
 el_val_t  http_response(el_val_t status, el_val_t headers_json, el_val_t body);
 
+/* SSE connection fd — set by http_worker_v2 before calling the El handler,
+ * cleared afterwards. Defined in el_seed.c; called from el_runtime.c.
+ * The getter is exposed as __http_conn_fd() to El programs. */
+void      el_seed_set_http_conn_fd(int fd);
+
 /* HTTP timeout — every libcurl request honors EL_HTTP_TIMEOUT_MS (default
  * 60000ms). Read lazily on first use, so setting the env var any time before
  * the first http_* call is sufficient.                                    */
@@ -742,6 +747,8 @@ el_val_t  map_set(el_val_t map, el_val_t key, el_val_t value); /* el_map_set */
 /* ── Subprocess execution ────────────────────────────────────────────────── */
 el_val_t exec_command(el_val_t cmd);   /* run shell command, return exit code */
 el_val_t exec_capture(el_val_t cmd);   /* run shell command, capture stdout   */
+el_val_t exec(el_val_t cmd);           /* exec(cmd) → stdout String (30s timeout) */
+el_val_t exec_bg(el_val_t cmd);        /* exec_bg(cmd) → PID String (non-blocking) */
 
 el_val_t emit_log(el_val_t level, el_val_t msg, el_val_t fields_json);
 el_val_t emit_metric(el_val_t name, el_val_t value, el_val_t tags_json);
@@ -749,6 +756,9 @@ el_val_t trace_span_start(el_val_t name);
 el_val_t trace_span_end(el_val_t span_handle);
 el_val_t emit_event(el_val_t name, el_val_t duration_ms);
 
+el_val_t __thread_create(el_val_t fn_name_v, el_val_t arg_v);
+el_val_t __thread_join(el_val_t tid_v);
+
 #ifdef __cplusplus
 }
 #endif

el-compiler/runtime/el_seed.h

@@ -0,0 +1,248 @@
+/*
+ * el_seed.h — El language seed runtime header
+ *
+ * Declares all OS-boundary primitives available to compiled El programs.
+ * All functions use the __ prefix convention. Signatures use el_val_t (= int64_t)
+ * as the universal value type.
+ *
+ * el_seed.c is the complete C boundary for the El runtime. The heavy runtime
+ * (el_runtime.c) has been retired — everything lives in el_seed.c plus the
+ * native El runtime (runtime/ *.el files).
+ *
+ * Link requirements:
+ *   -lcurl    — HTTP client (__http_do, __http_do_to_file)
+ *   -lpthread — threading (__thread_create, __thread_join, __mutex_new, ...)
+ *
+ * Canonical compile (via elb):
+ *   elb builds and links el_seed.c automatically.
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+
+/* ── Value model ─────────────────────────────────────────────────────────────
+ * All El values are el_val_t (int64_t). On 64-bit systems a pointer fits.
+ *   String  -> el_val_t  (holds const char* via uintptr_t cast)
+ *   Int     -> el_val_t  (stored directly)
+ *   Bool    -> el_val_t  (0 = false, nonzero = true)
+ *   Void    -> void
+ */
+typedef int64_t el_val_t;
+
+#define EL_STR(s)  ((el_val_t)(uintptr_t)(s))
+#define EL_CSTR(v) ((const char*)(uintptr_t)(v))
+#define EL_INT(v)  (v)
+#define EL_NULL    ((el_val_t)0)
+
+/* Float values share the el_val_t slot via bit-cast. */
+static inline double el_to_float(el_val_t v) {
+    union { int64_t i; double f; } u; u.i = (int64_t)v; return u.f;
+}
+static inline el_val_t el_from_float(double f) {
+    union { double f; int64_t i; } u; u.f = f; return (el_val_t)u.i;
+}
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* ── String primitives ───────────────────────────────────────────────────── */
+
+el_val_t  __str_len(el_val_t s);
+el_val_t  __str_char_at(el_val_t s, el_val_t i);       /* returns Int (byte value) */
+el_val_t  __str_alloc(el_val_t n);                     /* malloc(n+1), zero-init, return String */
+el_val_t  __str_set_char(el_val_t s, el_val_t i, el_val_t c);  /* s[i]=c, return s */
+el_val_t  __str_cmp(el_val_t a, el_val_t b);           /* strcmp result as Int */
+el_val_t  __str_ncmp(el_val_t a, el_val_t b, el_val_t n);      /* strncmp */
+el_val_t  __str_concat_raw(el_val_t a, el_val_t b);    /* malloc+strcpy concat */
+el_val_t  __str_slice_raw(el_val_t s, el_val_t start, el_val_t end);  /* substring copy */
+el_val_t  __int_to_str(el_val_t n);
+el_val_t  __str_to_int(el_val_t s);
+el_val_t  __float_to_str(el_val_t f);                  /* f is bit-cast double */
+el_val_t  __str_to_float(el_val_t s);                  /* strtod, bit-cast result */
+
+/* ── I/O ─────────────────────────────────────────────────────────────────── */
+
+void      __println(el_val_t s);
+void      __print(el_val_t s);
+el_val_t  __readline(void);
+
+/* ── Filesystem ──────────────────────────────────────────────────────────── */
+
+el_val_t  __fs_read(el_val_t path);
+el_val_t  __fs_write(el_val_t path, el_val_t content);
+el_val_t  __fs_exists(el_val_t path);
+el_val_t  __fs_list_raw(el_val_t path);               /* newline-separated filenames */
+el_val_t  __fs_mkdir(el_val_t path);
+el_val_t  __fs_write_bytes(el_val_t path, el_val_t bytes, el_val_t n);
+
+/* ── HTTP client ─────────────────────────────────────────────────────────── */
+
+/* Unified HTTP call. headers_json is a JSON object of header name->value pairs
+ * (e.g. {"Authorization":"Bearer ...","Content-Type":"application/json"}).
+ * Use "" or "{}" for no extra headers. timeout_ms <= 0 uses the default. */
+el_val_t  __http_do(el_val_t method, el_val_t url, el_val_t body,
+                    el_val_t headers_json, el_val_t timeout_ms);
+
+/* Stream response body directly to a file. Returns 1 on success, 0 on failure. */
+el_val_t  __http_do_to_file(el_val_t method, el_val_t url, el_val_t body,
+                             el_val_t headers_json, el_val_t out_path);
+
+/* ── HTTP server ─────────────────────────────────────────────────────────── */
+
+/* Blocking HTTP server. handler_name is the El function name to dispatch to.
+ * v1 handler: (method, path, body) -> String
+ * v2 handler: (method, path, headers_map, body) -> String or envelope */
+void      __http_serve(el_val_t port, el_val_t handler_name);
+void      __http_serve_v2(el_val_t port, el_val_t handler_name);
+
+/* Build a structured HTTP response envelope.
+ * headers_json: JSON object literal like {"Content-Type":"text/plain"} or "{}" */
+el_val_t  __http_response(el_val_t status, el_val_t headers_json, el_val_t body);
+
+/* ── HTTP SSE — Server-Sent Events streaming ─────────────────────────────── */
+
+/* Returns the raw file descriptor for the current HTTP connection.
+ * Valid only inside an http_serve_v2 handler before it returns.
+ * Returns -1 if called outside a handler context. */
+el_val_t  __http_conn_fd(void);
+
+/* Sends SSE response headers on conn_id (the fd from __http_conn_fd),
+ * keeping the connection open for streaming. Returns 1 on success, 0 on
+ * write failure. Call once at the start of an SSE handler. */
+el_val_t  __http_sse_open(el_val_t conn_id);
+
+/* Writes one SSE event frame: "data: <data>\n\n". data must not contain
+ * newlines. Returns 1 on success, 0 if the client disconnected. */
+el_val_t  __http_sse_send(el_val_t conn_id, el_val_t data);
+
+/* Closes the SSE connection. The handler must return http_sse_sentinel()
+ * so the HTTP worker does not double-close the fd. */
+el_val_t  __http_sse_close(el_val_t conn_id);
+
+/* ── Threading ───────────────────────────────────────────────────────────── */
+
+/* Create a thread that calls the named El function with a String argument.
+ * fn_name is resolved via dlsym(RTLD_DEFAULT, fn_name). Returns a thread
+ * handle Int that can be passed to __thread_join. Returns -1 on failure. */
+el_val_t  __thread_create(el_val_t fn_name, el_val_t arg);
+
+/* Wait for thread tid (returned by __thread_create) to finish.
+ * Returns the thread's return value as a String. */
+el_val_t  __thread_join(el_val_t tid);
+
+/* Allocate a new mutex. Returns a handle Int (index into internal table). */
+el_val_t  __mutex_new(void);
+
+void      __mutex_lock(el_val_t m);
+void      __mutex_unlock(el_val_t m);
+
+/* ── Subprocess ──────────────────────────────────────────────────────────── */
+
+el_val_t  __exec(el_val_t cmd);            /* popen, capture all stdout, return String */
+void      __exec_bg(el_val_t cmd);         /* fire and forget */
+
+/* ── Environment and process ─────────────────────────────────────────────── */
+
+el_val_t  __env_get(el_val_t key);         /* getenv, return "" if not set */
+void      __exit_program(el_val_t code);
+el_val_t  __args_json(void);               /* CLI args as JSON array string */
+
+/* ── Time ────────────────────────────────────────────────────────────────── */
+
+el_val_t  __time_now_ns(void);             /* clock_gettime REALTIME, nanoseconds */
+void      __sleep_ms(el_val_t ms);
+
+/* ── UUID ────────────────────────────────────────────────────────────────── */
+
+el_val_t  __uuid_v4(void);
+
+/* ── Math ────────────────────────────────────────────────────────────────── */
+
+el_val_t  __sqrt_f(el_val_t f);
+el_val_t  __log_f(el_val_t f);
+el_val_t  __ln_f(el_val_t f);
+el_val_t  __sin_f(el_val_t f);
+el_val_t  __cos_f(el_val_t f);
+el_val_t  __pi_f(void);
+
+/* ── JSON ────────────────────────────────────────────────────────────────── */
+
+el_val_t  __json_get(el_val_t json, el_val_t key);
+el_val_t  __json_get_raw(el_val_t json_str, el_val_t key);
+el_val_t  __json_parse(el_val_t s);
+el_val_t  __json_stringify(el_val_t v);
+el_val_t  __json_array_len(el_val_t json_str);
+el_val_t  __json_array_get(el_val_t json_str, el_val_t index);
+el_val_t  __json_array_get_string(el_val_t json_str, el_val_t index);
+el_val_t  __json_get_string(el_val_t json_str, el_val_t key);
+el_val_t  __json_get_int(el_val_t json_str, el_val_t key);
+el_val_t  __json_get_float(el_val_t json_str, el_val_t key);
+el_val_t  __json_get_bool(el_val_t json_str, el_val_t key);
+el_val_t  __json_set(el_val_t json_str, el_val_t key, el_val_t value);
+
+/* ── State K/V ───────────────────────────────────────────────────────────── */
+
+el_val_t  __state_set(el_val_t key, el_val_t value);
+el_val_t  __state_get(el_val_t key);
+el_val_t  __state_del(el_val_t key);
+el_val_t  __state_keys(void);
+
+/* ── HTML/URL ────────────────────────────────────────────────────────────── */
+
+el_val_t  __html_sanitize(el_val_t input_html, el_val_t allowlist_json);
+el_val_t  __url_encode(el_val_t s);
+el_val_t  __url_decode(el_val_t s);
+
+/* ── Engram ──────────────────────────────────────────────────────────────── */
+
+el_val_t  __engram_node(el_val_t content, el_val_t node_type, el_val_t salience);
+el_val_t  __engram_node_full(el_val_t content, el_val_t node_type, el_val_t label,
+                              el_val_t salience, el_val_t importance, el_val_t confidence,
+                              el_val_t tier, el_val_t tags);
+el_val_t  __engram_node_layered(el_val_t content, el_val_t node_type, el_val_t label,
+                                 el_val_t salience, el_val_t certainty, el_val_t confidence,
+                                 el_val_t status, el_val_t tags, el_val_t layer_id);
+el_val_t  __engram_add_layer(el_val_t name, el_val_t priority, el_val_t suppressible,
+                              el_val_t transparent, el_val_t injectable);
+el_val_t  __engram_remove_layer(el_val_t layer_id);
+el_val_t  __engram_list_layers(void);
+el_val_t  __engram_get_node(el_val_t id);
+void      __engram_strengthen(el_val_t node_id);
+void      __engram_forget(el_val_t node_id);
+el_val_t  __engram_node_count(void);
+el_val_t  __engram_search(el_val_t query, el_val_t limit);
+el_val_t  __engram_scan_nodes(el_val_t limit, el_val_t offset);
+void      __engram_connect(el_val_t from_id, el_val_t to_id, el_val_t weight, el_val_t relation);
+el_val_t  __engram_edge_between(el_val_t from_id, el_val_t to_id);
+el_val_t  __engram_neighbors(el_val_t node_id);
+el_val_t  __engram_neighbors_filtered(el_val_t node_id, el_val_t max_depth, el_val_t direction);
+el_val_t  __engram_edge_count(void);
+el_val_t  __engram_activate(el_val_t query, el_val_t depth);
+el_val_t  __engram_save(el_val_t path);
+el_val_t  __engram_load(el_val_t path);
+el_val_t  __engram_get_node_json(el_val_t id);
+el_val_t  __engram_search_json(el_val_t query, el_val_t limit);
+el_val_t  __engram_scan_nodes_json(el_val_t limit, el_val_t offset);
+el_val_t  __engram_scan_nodes_by_type_json(el_val_t node_type, el_val_t limit, el_val_t offset);
+el_val_t  __engram_neighbors_json(el_val_t node_id, el_val_t max_depth, el_val_t direction);
+el_val_t  __engram_activate_json(el_val_t query, el_val_t depth);
+el_val_t  __engram_stats_json(void);
+el_val_t  __engram_list_layers_json(void);
+el_val_t  __engram_compile_layered_json(el_val_t intent, el_val_t depth);
+
+/* ── Cryptographic hashing ────────────────────────────────────────────────── */
+
+/* __sha256_hex — return the SHA-256 hex digest of a string.
+ * The returned string is 64 hex characters (lowercase). */
+el_val_t  __sha256_hex(el_val_t s);
+
+/* ── args init (called from main) ────────────────────────────────────────── */
+/* Store argc/argv for __args_json. Call once at the start of main(). */
+void      el_seed_init_args(int argc, char** argv);
+
+#ifdef __cplusplus
+}
+#endif

el-compiler/runtime/legacy/el_runtime.h

@@ -0,0 +1,761 @@
+/*
+ * el_runtime.h — El language C runtime header
+ *
+ * Declares all built-in functions available to compiled El programs.
+ * Include this in every generated .c file.
+ *
+ * Value model:
+ *   All El values are represented as el_val_t (= int64_t).
+ *   On 64-bit systems a pointer fits in int64_t.
+ *   String values are cast: (el_val_t)(uintptr_t)"hello"
+ *   Integer values are stored directly.
+ *   This lets arithmetic work naturally while still passing strings around.
+ *
+ * Type conventions (El -> C):
+ *   String  -> el_val_t  (holds const char* via uintptr_t cast)
+ *   Int     -> el_val_t
+ *   Bool    -> el_val_t  (0 = false, nonzero = true)
+ *   Any     -> el_val_t
+ *   Void    -> void
+ *
+ * Macros for convenience:
+ *   EL_STR(s)    cast string literal to el_val_t
+ *   EL_CSTR(v)   cast el_val_t back to const char*
+ *   EL_INT(v)    identity — el_val_t is already int64_t
+ *
+ * Link requirements:
+ *   -lcurl     — required for the HTTP client (http_get, http_post, llm_*).
+ *   -lpthread  — required for the HTTP server (one detached thread per
+ *                connection, capped at 64 concurrent).
+ *   -loqs      — optional; required only when liboqs is installed and the
+ *                pq_* / sha3_256_hex entry points are needed. Detected at
+ *                compile time via __has_include(<oqs/oqs.h>).
+ *   -lcrypto   — optional; pulled in alongside -loqs. Used for X25519 in
+ *                pq_hybrid_* and HKDF-SHA256 derivation.
+ *
+ * Canonical compile command:
+ *   cc -std=c11 -I el-compiler/runtime -lcurl -lpthread \
+ *      -o <out> <prog>.c el-compiler/runtime/el_runtime.c
+ *
+ * With liboqs (post-quantum stack):
+ *   cc -std=c11 -I el-compiler/runtime -lcurl -lpthread -loqs -lcrypto \
+ *      -o <out> <prog>.c el-compiler/runtime/el_runtime.c
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+
+typedef int64_t el_val_t;
+
+#define EL_STR(s)  ((el_val_t)(uintptr_t)(s))
+#define EL_CSTR(v) ((const char*)(uintptr_t)(v))
+#define EL_INT(v)  (v)
+#define EL_NULL    ((el_val_t)0)
+
+/* Float values share the el_val_t (int64) slot via a bit-cast.
+ * The codegen emits Float literals as `el_from_float(<dbl>)` so the
+ * underlying bits represent the IEEE 754 double. Float-aware builtins
+ * (math, format, json) round-trip via these helpers. */
+static inline double el_to_float(el_val_t v) {
+    union { int64_t i; double f; } u;
+    u.i = (int64_t)v;
+    return u.f;
+}
+
+static inline el_val_t el_from_float(double f) {
+    union { double f; int64_t i; } u;
+    u.f = f;
+    return (el_val_t)u.i;
+}
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* ── I/O ──────────────────────────────────────────────────────────────────── */
+
+void      println(el_val_t s);
+void      print(el_val_t s);
+el_val_t  readline(void);
+
+/* ── String builtins ─────────────────────────────────────────────────────── */
+
+el_val_t  el_str_concat(el_val_t a, el_val_t b);
+el_val_t  str_eq(el_val_t a, el_val_t b);
+el_val_t  str_starts_with(el_val_t s, el_val_t prefix);
+el_val_t  str_ends_with(el_val_t s, el_val_t suffix);
+el_val_t  str_len(el_val_t s);
+el_val_t  str_concat(el_val_t a, el_val_t b);
+el_val_t  int_to_str(el_val_t n);
+el_val_t  str_to_int(el_val_t s);
+el_val_t  str_slice(el_val_t s, el_val_t start, el_val_t end);
+el_val_t  str_contains(el_val_t s, el_val_t sub);
+el_val_t  str_replace(el_val_t s, el_val_t from, el_val_t to);
+el_val_t  str_to_upper(el_val_t s);
+el_val_t  str_to_lower(el_val_t s);
+el_val_t  str_trim(el_val_t s);
+
+/* ── Math ────────────────────────────────────────────────────────────────── */
+
+el_val_t  el_abs(el_val_t n);
+el_val_t  el_max(el_val_t a, el_val_t b);
+el_val_t  el_min(el_val_t a, el_val_t b);
+
+/* ── Refcount (ARC) ──────────────────────────────────────────────────────────
+ * Lists and Maps carry a refcount. Strings and ints do not — el_retain and
+ * el_release are safe no-ops on non-refcounted values (they sniff a magic
+ * header at offset 0 and only act if the magic matches).
+ *
+ * Codegen emits these at let-binding shadowing, function entry (params), and
+ * function exit (locals other than the returned value). The refcount lets
+ * el_list_append and el_map_set mutate in place when uniquely owned (cheap)
+ * and copy-on-write when shared (preserves persistent semantics across
+ * accumulator patterns in the compiler itself).                              */
+
+void      el_retain(el_val_t v);
+void      el_release(el_val_t v);
+
+/* ── List ────────────────────────────────────────────────────────────────── */
+
+el_val_t  el_list_new(el_val_t count, ...);
+el_val_t  el_list_len(el_val_t list);
+el_val_t  el_list_get(el_val_t list, el_val_t index);
+el_val_t  el_list_append(el_val_t list, el_val_t elem);
+el_val_t  el_list_empty(void);
+el_val_t  el_list_clone(el_val_t list);
+
+/* ── Map ─────────────────────────────────────────────────────────────────── */
+
+el_val_t  el_map_new(el_val_t pair_count, ...);
+el_val_t  el_get_field(el_val_t map, el_val_t key);
+el_val_t  el_map_get(el_val_t map, el_val_t key);
+el_val_t  el_map_set(el_val_t map, el_val_t key, el_val_t value);
+
+/* ── HTTP ─────────────────────────────────────────────────────────────────── */
+
+el_val_t  http_get(el_val_t url);
+el_val_t  http_post(el_val_t url, el_val_t body);
+el_val_t  http_post_json(el_val_t url, el_val_t json_body);
+el_val_t  http_get_with_headers(el_val_t url, el_val_t headers_map);
+el_val_t  http_post_with_headers(el_val_t url, el_val_t body, el_val_t headers_map);
+el_val_t  http_post_form_auth(el_val_t url, el_val_t form_body, el_val_t auth_header);
+el_val_t  http_delete(el_val_t url);
+void      http_serve(el_val_t port, el_val_t handler);
+void      http_set_handler(el_val_t name);
+
+/* HTTP server v2 ─────────────────────────────────────────────────────────────
+ * Same dispatch model as http_serve, but the handler signature is widened:
+ *
+ *     el_val_t handler(method, path, headers_map, body)
+ *
+ * `headers_map` is an ElMap from lowercased header name → header value (both
+ * Strings). Repeated headers are joined with ", " per RFC 7230.
+ *
+ * Response value: the handler may return either
+ *   (a) a plain body string — same auto-content-type / 200-OK behaviour as
+ *       http_serve (3-arg) — or
+ *   (b) a response envelope built with `http_response(status, headers_json,
+ *       body)`. The runtime detects the envelope discriminator
+ *       `"el_http_response":1` at the start of the returned string and
+ *       unpacks status / headers / body before sending.
+ *
+ * The 3-arg http_serve(port, handler) remains supported unchanged for
+ * existing handlers (e.g. products/web/server.el): it dispatches with
+ * (method, path, body), hardcodes 200 OK, and auto-detects content type. */
+void      http_serve_v2(el_val_t port, el_val_t handler);
+void      http_set_handler_v2(el_val_t name);
+
+/* Build an HTTP response envelope. `headers_json` should be a JSON object
+ * literal like `{"WWW-Authenticate":"Basic"}` (or "" / "{}" for none). The
+ * returned string carries the discriminator `{"el_http_response":1,...}`
+ * which the runtime's send-path detects and unpacks. Detection happens
+ * uniformly inside http_send_response, so a 3-arg handler may also return
+ * an envelope. The 3-arg variant remains documented as a fixed 200-OK
+ * auto-content-type contract for legacy handlers that return plain bodies. */
+el_val_t  http_response(el_val_t status, el_val_t headers_json, el_val_t body);
+
+/* SSE connection fd — set by http_worker_v2 before calling the El handler,
+ * cleared afterwards. Defined in el_seed.c; called from el_runtime.c.
+ * The getter is exposed as __http_conn_fd() to El programs. */
+void      el_seed_set_http_conn_fd(int fd);
+
+/* HTTP timeout — every libcurl request honors EL_HTTP_TIMEOUT_MS (default
+ * 60000ms). Read lazily on first use, so setting the env var any time before
+ * the first http_* call is sufficient.                                    */
+
+/* Streaming variants — write the response body straight to a file via
+ * libcurl's CURLOPT_WRITEFUNCTION = fwrite. These bypass the el_val_t string
+ * wrapper entirely, so binary payloads (audio/mpeg, image/png, etc.) survive
+ * embedded NUL bytes that would truncate a strlen()-based code path.
+ *
+ * Both honor EL_HTTP_TIMEOUT_MS, follow redirects, and accept the same
+ * `headers_map` shape as http_post_with_headers (ElMap of String→String).
+ *
+ * Return value: 1 on success (file fully written), 0 on any failure
+ * (network, file open, partial write). On failure the output file is removed
+ * so callers cannot mistake a partially-written file for a valid one. */
+el_val_t  http_post_to_file(el_val_t url, el_val_t body, el_val_t headers_map, el_val_t output_path);
+el_val_t  http_get_to_file(el_val_t url, el_val_t headers_map, el_val_t output_path);
+
+/* ── URL encoding ────────────────────────────────────────────────────────── */
+
+el_val_t  url_encode(el_val_t s);   /* RFC 3986 unreserved set */
+el_val_t  url_decode(el_val_t s);   /* '+' → space, %XX → byte  */
+
+/* ── HTML allowlist sanitizer ────────────────────────────────────────────────
+ * el_html_sanitize(input_html, allowlist_json) — strict allowlist HTML
+ * cleaner. State-machine parser; tag/attribute names compared case-
+ * insensitively against the allowlist; `<a href>` / `<… src>` URL schemes
+ * validated (http, https, mailto, fragment-only, or relative); whole-
+ * subtree drop for script / style / iframe / object / embed / form; HTML-
+ * escapes free text outside dropped subtrees.
+ *
+ * The allowlist is JSON of the form
+ *     {"p":[],"a":["href","title"],"strong":[],...}
+ * where each value is the array of attribute names allowed for that tag. */
+el_val_t  el_html_sanitize(el_val_t input_html, el_val_t allowlist_json);
+
+/* ── Filesystem ──────────────────────────────────────────────────────────── */
+
+el_val_t  fs_read(el_val_t path);
+el_val_t  fs_write(el_val_t path, el_val_t content);
+el_val_t  fs_list(el_val_t path);
+el_val_t  fs_exists(el_val_t path);
+el_val_t  fs_mkdir(el_val_t path);   /* mkdir -p, mode 0755                */
+
+/* Length-explicit binary write. `length` is an Int (el_val_t holding the
+ * byte count). The caller knows the length from context — typically because
+ * `bytes` came from base64_decode (which produces a magic-tagged binary
+ * buffer with embedded NULs possible) and the caller already tracks the
+ * decoded length, OR because the bytes came from a fixed-size source
+ * (sha256_bytes = 32, hmac_sha256_bytes = 32). Bypasses strlen entirely.
+ *
+ * Returns 1 on success, 0 on failure (invalid path, can't open, partial
+ * write, negative length). On partial-write failure, the file is removed
+ * so callers cannot read back a truncated artefact. */
+el_val_t  fs_write_bytes(el_val_t path, el_val_t bytes, el_val_t length);
+
+/* ── JSON ────────────────────────────────────────────────────────────────── */
+
+el_val_t  json_get(el_val_t json, el_val_t key);
+el_val_t  json_parse(el_val_t s);
+el_val_t  json_stringify(el_val_t v);
+el_val_t  json_get_string(el_val_t json_str, el_val_t key);
+el_val_t  json_get_int(el_val_t json_str, el_val_t key);
+el_val_t  json_get_float(el_val_t json_str, el_val_t key);
+el_val_t  json_get_bool(el_val_t json_str, el_val_t key);
+el_val_t  json_get_raw(el_val_t json_str, el_val_t key);
+el_val_t  json_set(el_val_t json_str, el_val_t key, el_val_t value);
+el_val_t  json_array_len(el_val_t json_str);
+el_val_t  json_array_get(el_val_t json_str, el_val_t index);
+el_val_t  json_array_get_string(el_val_t json_str, el_val_t index);
+
+/* ── Time ────────────────────────────────────────────────────────────────── */
+
+el_val_t  time_now(void);
+el_val_t  time_now_utc(void);
+el_val_t  sleep_secs(el_val_t secs);
+el_val_t  sleep_ms(el_val_t ms);
+el_val_t  time_format(el_val_t ts, el_val_t fmt);
+el_val_t  time_to_parts(el_val_t ts);
+el_val_t  time_from_parts(el_val_t secs, el_val_t ns, el_val_t tz);
+el_val_t  time_add(el_val_t ts, el_val_t n, el_val_t unit);
+el_val_t  time_diff(el_val_t ts1, el_val_t ts2, el_val_t unit);
+
+/* ── Instant + Duration: first-class temporal types ──────────────────────────
+ * Both types share the el_val_t (int64) slot. Instants are nanoseconds
+ * since the Unix epoch; Durations are signed nanoseconds. Type discipline
+ * is enforced at codegen-time: BinOps on names registered as Instant or
+ * Duration route through the typed wrappers below; mismatches like
+ * Instant+Instant become #error at the C compiler.
+ *
+ * Postfix literals — `30.seconds`, `1.hour`, `500.millis`, `30.nanos` — are
+ * recognised by the parser as DurationLit AST nodes and lowered to literal
+ * int64 nanoseconds at codegen time. The runtime never sees the units. */
+
+el_val_t  el_now_instant(void);
+el_val_t  now(void);
+el_val_t  unix_seconds(el_val_t n);
+el_val_t  unix_millis(el_val_t n);
+el_val_t  instant_from_iso8601(el_val_t s);
+
+el_val_t  el_duration_from_nanos(el_val_t ns);
+el_val_t  duration_seconds(el_val_t n);
+el_val_t  duration_millis(el_val_t n);
+el_val_t  duration_nanos(el_val_t n);
+
+el_val_t  el_instant_add_dur(el_val_t inst, el_val_t dur);
+el_val_t  el_instant_sub_dur(el_val_t inst, el_val_t dur);
+el_val_t  el_instant_diff(el_val_t a, el_val_t b);
+el_val_t  el_duration_add(el_val_t a, el_val_t b);
+el_val_t  el_duration_sub(el_val_t a, el_val_t b);
+el_val_t  el_duration_scale(el_val_t dur, el_val_t scalar);
+el_val_t  el_duration_div(el_val_t dur, el_val_t scalar);
+
+el_val_t  el_instant_lt(el_val_t a, el_val_t b);
+el_val_t  el_instant_le(el_val_t a, el_val_t b);
+el_val_t  el_instant_gt(el_val_t a, el_val_t b);
+el_val_t  el_instant_ge(el_val_t a, el_val_t b);
+el_val_t  el_instant_eq(el_val_t a, el_val_t b);
+el_val_t  el_instant_ne(el_val_t a, el_val_t b);
+el_val_t  el_duration_lt(el_val_t a, el_val_t b);
+el_val_t  el_duration_le(el_val_t a, el_val_t b);
+el_val_t  el_duration_gt(el_val_t a, el_val_t b);
+el_val_t  el_duration_ge(el_val_t a, el_val_t b);
+el_val_t  el_duration_eq(el_val_t a, el_val_t b);
+el_val_t  el_duration_ne(el_val_t a, el_val_t b);
+
+el_val_t  instant_to_unix_seconds(el_val_t i);
+el_val_t  instant_to_unix_millis(el_val_t i);
+el_val_t  instant_to_iso8601(el_val_t i);
+el_val_t  duration_to_seconds(el_val_t d);
+el_val_t  duration_to_millis(el_val_t d);
+el_val_t  duration_to_nanos(el_val_t d);
+
+el_val_t  el_sleep_duration(el_val_t dur);
+el_val_t  unix_timestamp(void);
+
+el_val_t  ttl_cache_set(el_val_t key, el_val_t value);
+el_val_t  ttl_cache_get(el_val_t key, el_val_t max_age);
+el_val_t  ttl_cache_age(el_val_t key);
+
+/* ── Calendar + CalendarTime + Rhythm + LocalDate/Time/DateTime ─────────────
+ * Phase 1.5 of the time system. Calendar is pluggable: EarthCalendar (IANA
+ * zones, Gregorian, DST) is the user-facing default; MarsCalendar,
+ * CycleCalendar(period), NoCycleCalendar, RelativeCalendar handle non-Earth
+ * domains.
+ *
+ * A Calendar interprets an Instant under a particular cycle convention and
+ * produces a CalendarTime. CalendarTime carries the underlying Instant and
+ * a back-pointer to its Calendar; arithmetic and formatting consult the
+ * Calendar to convert ns since epoch into year/month/day/hour/minute/second
+ * (or sol/phase, or cycle/phase, depending on kind).
+ *
+ * Storage convention: Calendar / CalendarTime / Rhythm / LocalDate /
+ * LocalDateTime are heap-allocated structs whose pointers are cast into
+ * el_val_t. A 24-bit magic header at offset 0 lets the runtime identify
+ * the kind safely. LocalTime is small enough to live in the int64 slot
+ * directly (nanos since midnight, signed).                                  */
+
+/* Zone — opaque IANA zone or fixed offset, used by EarthCalendar.
+ * `zone_id` is either an IANA name ("America/New_York", "UTC") or a fixed
+ * offset string ("+05:30", "-08:00"). The runtime resolves it via tzset()
+ * on first use of the owning EarthCalendar.                                  */
+el_val_t  zone(el_val_t id);
+el_val_t  zone_utc(void);
+el_val_t  zone_local(void);
+el_val_t  zone_offset(el_val_t hours, el_val_t minutes);
+
+/* Calendar constructors. Each returns an el_val_t pointer to a heap-
+ * allocated, magic-tagged Calendar struct. Calendars are interned by
+ * (kind, zone_id, period_ns, epoch_ns) so identical constructors return
+ * the same pointer — equality is reference equality.                        */
+el_val_t  earth_calendar(el_val_t z);
+el_val_t  earth_calendar_default(void);
+el_val_t  mars_calendar(void);
+el_val_t  cycle_calendar(el_val_t period_dur);
+el_val_t  no_cycle_calendar(void);
+el_val_t  relative_calendar(el_val_t epoch_inst);
+
+/* CalendarTime constructors and methods. Returns a heap-allocated struct
+ * whose pointer fits in el_val_t. */
+el_val_t  now_in(el_val_t cal);
+el_val_t  in_calendar(el_val_t inst, el_val_t cal);
+el_val_t  cal_format(el_val_t ct, el_val_t pattern);
+el_val_t  cal_to_instant(el_val_t ct);
+el_val_t  cal_cycle_phase(el_val_t ct);
+el_val_t  cal_in(el_val_t ct, el_val_t cal);
+
+/* LocalDate / LocalTime / LocalDateTime — calendar-agnostic value types.
+ * LocalTime carries nanoseconds since midnight as a signed int64 directly
+ * in the el_val_t slot (no allocation). LocalDate / LocalDateTime are
+ * heap-allocated structs with magic headers. */
+el_val_t  local_date(el_val_t y, el_val_t m, el_val_t d);
+el_val_t  local_time(el_val_t h, el_val_t m, el_val_t s, el_val_t ns);
+el_val_t  local_datetime(el_val_t date, el_val_t time);
+el_val_t  zoned(el_val_t date, el_val_t time, el_val_t cal);
+
+el_val_t  local_date_year(el_val_t ld);
+el_val_t  local_date_month(el_val_t ld);
+el_val_t  local_date_day(el_val_t ld);
+el_val_t  local_time_hour(el_val_t lt);
+el_val_t  local_time_minute(el_val_t lt);
+el_val_t  local_time_second(el_val_t lt);
+el_val_t  local_time_nanos(el_val_t lt);
+
+el_val_t  el_local_date_add_dur(el_val_t ld, el_val_t dur);
+el_val_t  el_local_time_add_dur(el_val_t lt, el_val_t dur);
+el_val_t  el_local_date_lt(el_val_t a, el_val_t b);
+el_val_t  el_local_date_eq(el_val_t a, el_val_t b);
+
+/* Rhythm — pluggable recurrence AST. Returns a heap-allocated struct
+ * pointer in el_val_t; rhythms are immutable so callers may share them. */
+el_val_t  rhythm_cycle_start(void);
+el_val_t  rhythm_cycle_phase(el_val_t phase);
+el_val_t  rhythm_duration(el_val_t d);
+el_val_t  rhythm_session_start(void);
+el_val_t  rhythm_event(el_val_t name);
+el_val_t  rhythm_and(el_val_t a, el_val_t b);
+el_val_t  rhythm_or(el_val_t a, el_val_t b);
+el_val_t  rhythm_weekday(el_val_t day);
+el_val_t  rhythm_weekly_at(el_val_t day, el_val_t hour, el_val_t minute);
+el_val_t  rhythm_next_after(el_val_t r, el_val_t after, el_val_t cal);
+el_val_t  rhythm_matches(el_val_t r, el_val_t ct);
+
+/* ── UUID ────────────────────────────────────────────────────────────────── */
+
+el_val_t  uuid_new(void);
+el_val_t  uuid_v4(void);
+
+/* ── Environment ─────────────────────────────────────────────────────────── */
+
+el_val_t  env(el_val_t key);
+
+/* ── In-process state K/V ────────────────────────────────────────────────── */
+
+el_val_t  state_set(el_val_t key, el_val_t value);
+el_val_t  state_get(el_val_t key);
+el_val_t  state_del(el_val_t key);
+el_val_t  state_keys(void);
+
+/* ── Float formatting ────────────────────────────────────────────────────── */
+
+el_val_t  float_to_str(el_val_t f);
+el_val_t  int_to_float(el_val_t n);
+el_val_t  float_to_int(el_val_t f);
+el_val_t  format_float(el_val_t f, el_val_t decimals);
+el_val_t  decimal_round(el_val_t f, el_val_t decimals);
+el_val_t  str_to_float(el_val_t s);
+
+/* ── Math (Float-aware) ──────────────────────────────────────────────────── */
+
+el_val_t  math_sqrt(el_val_t f);
+el_val_t  math_log(el_val_t f);
+el_val_t  math_ln(el_val_t f);
+el_val_t  math_sin(el_val_t f);
+el_val_t  math_cos(el_val_t f);
+el_val_t  math_pi(void);
+
+/* ── String additions ────────────────────────────────────────────────────── */
+
+el_val_t  str_index_of(el_val_t s, el_val_t sub);
+el_val_t  str_split(el_val_t s, el_val_t sep);
+el_val_t  str_char_at(el_val_t s, el_val_t i);
+el_val_t  str_char_code(el_val_t s, el_val_t i);
+el_val_t  str_pad_left(el_val_t s, el_val_t width, el_val_t pad);
+el_val_t  str_pad_right(el_val_t s, el_val_t width, el_val_t pad);
+el_val_t  str_format(el_val_t fmt, el_val_t data);
+el_val_t  str_lower(el_val_t s);
+el_val_t  str_upper(el_val_t s);
+
+/* ── Text-processing primitives (Phase 1: byte/codepoint, ASCII char classes)
+ * Phase 2 (filed): Unicode-grapheme awareness, NFC/NFD normalization, regex.
+ * is_* predicates: empty input returns false; multi-char requires ALL bytes
+ * to match. ASCII ranges only in Phase 1. */
+
+/* Counting */
+el_val_t  str_count(el_val_t s, el_val_t sub);              /* non-overlapping */
+el_val_t  str_count_chars(el_val_t s);                      /* codepoint count */
+el_val_t  str_count_bytes(el_val_t s);                      /* alias of str_len */
+el_val_t  str_count_lines(el_val_t s);
+el_val_t  str_count_words(el_val_t s);
+el_val_t  str_count_letters(el_val_t s);                    /* ASCII [A-Za-z] */
+el_val_t  str_count_digits(el_val_t s);                     /* ASCII [0-9] */
+
+/* Find / position */
+el_val_t  str_index_of_all(el_val_t s, el_val_t sub);       /* [Int] of byte offsets */
+el_val_t  str_last_index_of(el_val_t s, el_val_t sub);
+el_val_t  str_find_chars(el_val_t s, el_val_t any_of);      /* first idx of any ch */
+
+/* Transform */
+el_val_t  str_repeat(el_val_t s, el_val_t n);
+el_val_t  str_reverse(el_val_t s);                          /* by codepoint */
+el_val_t  str_strip_prefix(el_val_t s, el_val_t prefix);
+el_val_t  str_strip_suffix(el_val_t s, el_val_t suffix);
+el_val_t  str_strip_chars(el_val_t s, el_val_t chars);
+el_val_t  str_lstrip(el_val_t s);
+el_val_t  str_rstrip(el_val_t s);
+
+/* Char classification (Bool) */
+el_val_t  is_letter(el_val_t s);
+el_val_t  is_digit(el_val_t s);
+el_val_t  is_alphanumeric(el_val_t s);
+el_val_t  is_whitespace(el_val_t s);
+el_val_t  is_punctuation(el_val_t s);
+el_val_t  is_uppercase(el_val_t s);
+el_val_t  is_lowercase(el_val_t s);
+
+/* Split / join */
+el_val_t  str_split_lines(el_val_t s);
+el_val_t  str_split_chars(el_val_t s);                      /* alias of native_string_chars */
+el_val_t  str_split_n(el_val_t s, el_val_t sep, el_val_t n);
+el_val_t  str_join(el_val_t list, el_val_t sep);            /* alias of list_join */
+
+/* ── List additions ──────────────────────────────────────────────────────── */
+
+el_val_t  list_push(el_val_t list, el_val_t elem);
+el_val_t  list_push_front(el_val_t list, el_val_t elem);
+el_val_t  list_join(el_val_t list, el_val_t sep);
+el_val_t  list_range(el_val_t start, el_val_t end);
+
+/* ── Bool helpers ────────────────────────────────────────────────────────── */
+
+el_val_t  bool_to_str(el_val_t b);
+
+/* ── Numeric parsing ─────────────────────────────────────────────────────── */
+
+el_val_t  parse_int(el_val_t s, el_val_t default_val);
+
+/* ── Process ─────────────────────────────────────────────────────────────── */
+
+void      exit_program(el_val_t code);
+el_val_t  getpid_now(void);
+
+/* ── CGI identity ─────────────────────────────────────────────────────────────
+ * Called at the start of main() in CGI programs (those with a `cgi {}` block).
+ * Records the program's DHARMA identity before any other code executes.      */
+
+void      el_cgi_init(el_val_t name, el_val_t dharma_id, el_val_t principal,
+                      el_val_t network, el_val_t engram);
+
+/* ── DHARMA network builtins ─────────────────────────────────────────────────
+ * Available to CGI programs (declared with a `cgi {}` block).
+ *
+ * Peers are addressed by `dharma_id` of the form
+ *     "<registry-id>@<transport-url>"   e.g. "ntn-genesis@http://localhost:7770"
+ * If the @<url> portion is omitted, transport defaults to
+ * "http://localhost:7770" (the local CGI daemon assumption).
+ *
+ * Wire protocol (all peers expose):
+ *   POST <url>/dharma/recv      { channel, from, content } → response body
+ *   POST <url>/dharma/event     { type, payload, source, timestamp }
+ *   POST <url>/api/activate     { query }                 → list of nodes
+ *
+ * Hosting application's responsibility: an El program with a `cgi {}` block
+ * runs http_serve() with its own request handler; that handler should route
+ * "/dharma/event" requests by calling el_runtime_dharma_event_arrive() so
+ * incoming events feed dharma_field() queues. The runtime itself does not
+ * intercept any /dharma path.                                                */
+
+el_val_t  dharma_connect(el_val_t cgi_id);
+el_val_t  dharma_send(el_val_t channel, el_val_t content);
+el_val_t  dharma_activate(el_val_t query);
+void      dharma_emit(el_val_t event_type, el_val_t payload);
+el_val_t  dharma_field(el_val_t event_type);
+void      dharma_strengthen(el_val_t cgi_id, el_val_t weight);
+el_val_t  dharma_relationship(el_val_t cgi_id);
+el_val_t  dharma_peers(void);
+
+/* Public C API: called by an El program's HTTP handler when a /dharma/event
+ * request arrives. Pushes onto the per-event-type queue and signals any
+ * pending dharma_field() blockers. All three arguments must be NUL-terminated
+ * C strings (or NULL — then treated as empty).                               */
+void      el_runtime_dharma_event_arrive(const char* event_type,
+                                         const char* payload,
+                                         const char* source);
+
+/* ── Engram local graph primitives ───────────────────────────────────────────
+ * Operate on the CGI's local Engram knowledge graph.
+ * `engram_activate` queries the local graph only; `dharma_activate` is
+ * network-wide across all connected CGI graphs.                              */
+
+el_val_t  engram_node(el_val_t content, el_val_t node_type, el_val_t salience);
+el_val_t  engram_node_full(el_val_t content, el_val_t node_type, el_val_t label,
+                           el_val_t salience, el_val_t importance, el_val_t confidence,
+                           el_val_t tier, el_val_t tags);
+/* Layered consciousness — see el_runtime.c for the layered architecture
+ * design notes (search "Layered consciousness architecture"). The five
+ * canonical layers (safety / core-identity / domain-knowledge / imprint /
+ * suit) are seeded automatically; engram_add_layer extends the registry
+ * with imprint or suit overlays at runtime. Nodes default to layer 1
+ * (core-identity) when created via engram_node / engram_node_full. */
+el_val_t  engram_node_layered(el_val_t content, el_val_t node_type, el_val_t label,
+                              el_val_t salience, el_val_t certainty, el_val_t confidence,
+                              el_val_t status, el_val_t tags, el_val_t layer_id);
+el_val_t  engram_add_layer(el_val_t name, el_val_t priority, el_val_t suppressible,
+                           el_val_t transparent, el_val_t injectable);
+el_val_t  engram_remove_layer(el_val_t layer_id);
+el_val_t  engram_list_layers(void);
+el_val_t  engram_get_node(el_val_t id);
+void      engram_strengthen(el_val_t node_id);
+void      engram_forget(el_val_t node_id);
+el_val_t  engram_node_count(void);
+el_val_t  engram_search(el_val_t query, el_val_t limit);
+el_val_t  engram_scan_nodes(el_val_t limit, el_val_t offset);
+void      engram_connect(el_val_t from_id, el_val_t to_id, el_val_t weight, el_val_t relation);
+el_val_t  engram_edge_between(el_val_t from_id, el_val_t to_id);
+el_val_t  engram_neighbors(el_val_t node_id);
+el_val_t  engram_neighbors_filtered(el_val_t node_id, el_val_t max_depth, el_val_t direction);
+el_val_t  engram_edge_count(void);
+/* Three-pass activation: background fan-out → working-memory promotion →
+ * Layer 0 override. See "Three-pass activation" in el_runtime.c. */
+el_val_t  engram_activate(el_val_t query, el_val_t depth);
+el_val_t  engram_save(el_val_t path);
+el_val_t  engram_load(el_val_t path);
+
+/* JSON-string accessors — return pre-serialized JSON so HTTP handlers
+ * can pass results straight through without round-tripping ElList/ElMap
+ * through json_stringify. */
+el_val_t  engram_get_node_json(el_val_t id);
+el_val_t  engram_search_json(el_val_t query, el_val_t limit);
+el_val_t  engram_scan_nodes_json(el_val_t limit, el_val_t offset);
+el_val_t  engram_scan_nodes_by_type_json(el_val_t node_type, el_val_t limit, el_val_t offset);
+el_val_t  engram_neighbors_json(el_val_t node_id, el_val_t max_depth, el_val_t direction);
+el_val_t  engram_activate_json(el_val_t query, el_val_t depth);
+el_val_t  engram_stats_json(void);
+el_val_t  engram_list_layers_json(void);
+/* engram_compile_layered_json — produce a prompt-ready text block split
+ * into "[LAYER 0 — STRUCTURAL]" (non-suppressible layers, sacred fire)
+ * and "[ENGRAM CONTEXT]" (standard suppressible layers). Returns "" if
+ * no nodes promoted to working memory. */
+el_val_t  engram_compile_layered_json(el_val_t intent, el_val_t depth);
+
+/* ── LLM (Anthropic API client) ─────────────────────────────────────────────
+ * All functions call https://api.anthropic.com/v1/messages with the API key
+ * from env ANTHROPIC_API_KEY. Default model when empty: claude-sonnet-4-5. */
+
+el_val_t  llm_call(el_val_t model, el_val_t prompt);
+el_val_t  llm_call_system(el_val_t model, el_val_t system_prompt, el_val_t user_prompt);
+el_val_t  llm_call_agentic(el_val_t model, el_val_t system, el_val_t user, el_val_t tools);
+el_val_t  llm_vision(el_val_t model, el_val_t system, el_val_t prompt, el_val_t image_url_or_b64);
+el_val_t  llm_models(void);
+
+/* Register a tool handler by name. The handler is looked up via dlsym
+ * (mirroring http_set_handler), so any El `fn <name>(input)` compiles to
+ * a global C symbol that this function can locate at runtime.
+ * Handler signature: `el_val_t handler(el_val_t input_json)` — receives
+ * the tool input as a JSON-string el_val_t and returns a JSON-string
+ * el_val_t result. Used by llm_call_agentic.                                 */
+void      llm_register_tool(el_val_t name, el_val_t handler_fn_name);
+
+/* ── args() ─────────────────────────────────────────────────────────────────
+ * Provides access to command-line arguments passed to the program.
+ * Populated by el_runtime_init_args() before main() runs.           */
+
+el_val_t  args(void);
+void      el_runtime_init_args(int argc, char** argv);
+
+/* ── Crypto primitives ─────────────────────────────────────────────────────
+ * SHA-256, HMAC-SHA-256, and base64 (standard + URL-safe).
+ * Self-contained — no OpenSSL/libcrypto dependency. The implementations are
+ * adapted from public-domain reference code (Brad Conte / RFC 4648).
+ *
+ * Bytes-returning variants (sha256_bytes, hmac_sha256_bytes) return a string
+ * value whose contents are raw binary; callers usually feed these into
+ * base64_encode. Note that el_val_t strings are NUL-terminated by convention,
+ * so the binary payload may contain embedded NULs — pass it directly into
+ * base64_encode (which uses an explicit length) rather than treating it as
+ * a printable C string.
+ *
+ * The "base64" variants emit/accept RFC 4648 standard alphabet with padding.
+ * The "base64url" variants use URL-safe alphabet (`-`/`_`) with no padding,
+ * as used in JWTs.                                                           */
+
+el_val_t  sha256_hex(el_val_t input);
+el_val_t  sha256_bytes(el_val_t input);
+el_val_t  hmac_sha256_hex(el_val_t key, el_val_t message);
+el_val_t  hmac_sha256_bytes(el_val_t key, el_val_t message);
+el_val_t  base64_encode(el_val_t input);
+el_val_t  base64_decode(el_val_t input);
+el_val_t  base64url_encode(el_val_t input);
+el_val_t  base64url_decode(el_val_t input);
+
+/* Length-aware variants (internal — exposed for the rare caller that already
+ * has a known-length binary buffer and doesn't want to round-trip through
+ * a NUL-terminated el_val_t string). Sha256_bytes and hmac_sha256_bytes feed
+ * these implicitly. */
+el_val_t  el_sha256_bytes_n(const unsigned char* data, size_t len);
+el_val_t  el_base64_encode_n(const unsigned char* data, size_t len, int url_safe);
+
+/* ── Post-quantum primitives (liboqs-backed) ────────────────────────────────
+ * All inputs/outputs hex-encoded. Algorithm choices:
+ *   Signature: CRYSTALS-Dilithium-3   (NIST level 3, balanced)
+ *   KEM:       CRYSTALS-Kyber-768     (NIST level 3)
+ *   Hash:      SHA3-256 (Keccak)      (PQ-aware protocols favour SHA3 over SHA2)
+ *
+ * If liboqs is not linked (detected via __has_include(<oqs/oqs.h>) at compile
+ * time), the pq_* entry points return a JSON-shaped error string so callers
+ * fail loudly rather than silently fall back to classical schemes:
+ *   {"error":"liboqs not linked, post-quantum primitives unavailable"}
+ *
+ * The hybrid handshake pairs X25519 with Kyber-768 per NIST PQ guidance and
+ * CNSA 2.0. Combined shared secret is HKDF-SHA256(x25519_ss || kyber_ss).
+ * Even if Kyber falls, X25519 holds; if X25519 falls under quantum attack,
+ * Kyber holds. SHA3-256 also remains usable independent of liboqs (the
+ * Keccak permutation is PQ-OK as a primitive). */
+
+el_val_t  pq_keygen_signature(void);
+el_val_t  pq_sign(el_val_t secret_key_hex, el_val_t message);
+el_val_t  pq_verify(el_val_t public_key_hex, el_val_t message, el_val_t signature_hex);
+
+el_val_t  pq_kem_keygen(void);
+el_val_t  pq_kem_encaps(el_val_t public_key_hex);
+el_val_t  pq_kem_decaps(el_val_t secret_key_hex, el_val_t ciphertext_hex);
+
+el_val_t  pq_hybrid_keygen(void);
+el_val_t  pq_hybrid_handshake(el_val_t remote_pub_combined);
+
+el_val_t  sha3_256_hex(el_val_t input);
+
+/* ── AEAD: AES-256-GCM (libcrypto-backed) ───────────────────────────────────
+ * Symmetric authenticated encryption used to wrap envelopes after a KEM
+ * handshake. Caller MUST supply a 32-byte key (64 hex chars) — typically the
+ * Kyber-768 / hybrid shared_secret, optionally normalized via SHA3-256.
+ *
+ * aead_encrypt returns a JSON map {"nonce":"...","ciphertext":"..."} where
+ * ciphertext is the AES-256-GCM output with the 16-byte auth tag appended.
+ * Nonce is a fresh 12-byte CSPRNG draw — callers never pick the nonce, which
+ * structurally rules out the GCM nonce-reuse footgun.
+ *
+ * aead_decrypt returns the plaintext String, or "" on any failure (including
+ * auth-tag mismatch). Callers MUST check for "" before trusting the result. */
+el_val_t  aead_encrypt(el_val_t key_hex, el_val_t plaintext);
+el_val_t  aead_decrypt(el_val_t key_hex, el_val_t nonce_hex, el_val_t ciphertext_hex);
+
+/* ── Native VM builtin aliases (for compiled El source) ─────────────────────
+ * These match the El VM's native_* builtins so that El source compiled
+ * to C can call the same names without modification.                */
+
+el_val_t  native_list_get(el_val_t list, el_val_t index);
+el_val_t  native_list_len(el_val_t list);
+el_val_t  native_list_append(el_val_t list, el_val_t elem);
+el_val_t  native_list_empty(void);
+el_val_t  native_list_clone(el_val_t list);
+el_val_t  native_string_chars(el_val_t s);
+el_val_t  native_int_to_str(el_val_t n);
+
+/* ── Method-call shorthand aliases ──────────────────────────────────────────
+ * The El method-call convention `obj.method(args)` compiles to
+ * `method(obj, args)`.  These aliases expose the runtime functions under
+ * the short names that result from method calls in El source.
+ *
+ * Example: `myList.append(x)` → `append(myList, x)` (calls this alias)
+ *          `myList.len()`     → `len(myList)`         (calls this alias)  */
+
+el_val_t  append(el_val_t list, el_val_t elem);   /* el_list_append */
+el_val_t  len(el_val_t list);                      /* el_list_len    */
+el_val_t  get(el_val_t list, el_val_t index);      /* el_list_get    */
+el_val_t  map_get(el_val_t map, el_val_t key);     /* el_map_get     */
+el_val_t  map_set(el_val_t map, el_val_t key, el_val_t value); /* el_map_set */
+
+/* ── OTLP/HTTP Observability ─────────────────────────────────────────────── */
+/* See bottom of el_runtime.c for the implementation.
+ * Configured by env vars OTLP_ENDPOINT, OTEL_SERVICE_NAME, OTEL_SERVICE_VERSION.
+ * No-op when OTLP_ENDPOINT is unset. Drop-on-failure semantics. */
+/* ── Subprocess execution ────────────────────────────────────────────────── */
+el_val_t exec_command(el_val_t cmd);   /* run shell command, return exit code */
+el_val_t exec_capture(el_val_t cmd);   /* run shell command, capture stdout   */
+el_val_t exec(el_val_t cmd);           /* exec(cmd) → stdout String (30s timeout) */
+el_val_t exec_bg(el_val_t cmd);        /* exec_bg(cmd) → PID String (non-blocking) */
+
+el_val_t emit_log(el_val_t level, el_val_t msg, el_val_t fields_json);
+el_val_t emit_metric(el_val_t name, el_val_t value, el_val_t tags_json);
+el_val_t trace_span_start(el_val_t name);
+el_val_t trace_span_end(el_val_t span_handle);
+el_val_t emit_event(el_val_t name, el_val_t duration_ms);
+
+#ifdef __cplusplus
+}
+#endif

el-compiler/src/codegen.el

@@ -135,8 +135,9 @@ fn emit_blank() -> Void {
 fn binop_to_c(op: String) -> String {
     if op == "Plus"  { return "+" }
     if op == "Minus" { return "-" }
-    if op == "Star"  { return "*" }
-    if op == "Slash" { return "/" }
+    if op == "Star"    { return "*" }
+    if op == "Slash"   { return "/" }
+    if op == "Percent" { return "%" }
     if op == "EqEq"  { return "==" }
     if op == "NotEq" { return "!=" }
     if op == "Lt"    { return "<" }
@@ -861,6 +862,97 @@ fn cg_match(expr: Map<String, Any>) -> String {
     str_join(parts, "")
 }
 
+// Lower a match statement (used for side effects, not as an expression) to a
+// chain of C if/else if/else blocks. The subject is evaluated once into a
+// scoped temporary; each arm generates a condition and a braced body; the
+// wildcard/binding arm becomes the final `else` branch.
+//
+// Pattern dispatch:
+//   LitStr  -> str_eq(subj, EL_STR("..."))
+//   LitInt  -> subj == N
+//   LitBool -> subj == 1 / subj == 0
+//   Binding -> else { el_val_t name = subj; <body> }
+//   Wildcard -> else { <body> }
+fn cg_match_stmt(expr: Map<String, Any>, indent: String, declared: [String]) -> Void {
+    let subject = expr["subject"]
+    let arms = expr["arms"]
+    let subj_c: String = cg_expr(subject)
+    let id: String = next_match_id()
+    let subj_var: String = "_match_subj_" + id
+    let inner: String = indent + "  "
+    emit_line(indent + "{")
+    emit_line(inner + "el_val_t " + subj_var + " = " + subj_c + ";")
+    let n: Int = native_list_len(arms)
+    let i = 0
+    let first_cond: Bool = true
+    while i < n {
+        let arm = native_list_get(arms, i)
+        let pat = arm["pattern"]
+        let body = arm["body"]
+        let pkind: String = pat["pattern"]
+        let body_c: String = cg_expr(body)
+        if str_eq(pkind, "LitStr") {
+            let v: String = pat["value"]
+            let cond_str = "str_eq(" + subj_var + ", EL_STR(" + c_str_lit(v) + "))"
+            if first_cond {
+                emit_line(inner + "if (" + cond_str + ") {")
+                let first_cond = false
+            } else {
+                emit_line(inner + "} else if (" + cond_str + ") {")
+            }
+            emit_line(inner + "  " + body_c + ";")
+        } else {
+            if str_eq(pkind, "LitInt") {
+                let v: String = pat["value"]
+                let cond_str = subj_var + " == " + v
+                if first_cond {
+                    emit_line(inner + "if (" + cond_str + ") {")
+                    let first_cond = false
+                } else {
+                    emit_line(inner + "} else if (" + cond_str + ") {")
+                }
+                emit_line(inner + "  " + body_c + ";")
+            } else {
+                if str_eq(pkind, "LitBool") {
+                    let v: String = pat["value"]
+                    let bv = "0"
+                    if str_eq(v, "true") {
+                        let bv = "1"
+                    }
+                    let cond_str = subj_var + " == " + bv
+                    if first_cond {
+                        emit_line(inner + "if (" + cond_str + ") {")
+                        let first_cond = false
+                    } else {
+                        emit_line(inner + "} else if (" + cond_str + ") {")
+                    }
+                    emit_line(inner + "  " + body_c + ";")
+                } else {
+                    // Wildcard or Binding - becomes the else branch
+                    if first_cond {
+                        emit_line(inner + "{")
+                    } else {
+                        emit_line(inner + "} else {")
+                    }
+                    if str_eq(pkind, "Binding") {
+                        let bname: String = pat["name"]
+                        emit_line(inner + "  el_val_t " + bname + " = " + subj_var + ";")
+                    }
+                    emit_line(inner + "  " + body_c + ";")
+                    emit_line(inner + "}")
+                    let first_cond = true
+                }
+            }
+        }
+        let i = i + 1
+    }
+    // Close any open if/else-if chain (only reached when last arm was a literal pattern)
+    if !first_cond {
+        emit_line(inner + "}")
+    }
+    emit_line(indent + "}")
+}
+
 // -- If-as-expression codegen -------------------------------------------------
 //
 // Lower `if cond { thenBody } else { elseBody }` used in expression position
@@ -1078,6 +1170,16 @@ fn cg_stmt(stmt: Map<String, Any>, indent: String, declared: [String]) -> [Strin
         return declared
     }
 
+    if kind == "Break" {
+        emit_line(indent + "break;")
+        return declared
+    }
+
+    if kind == "Continue" {
+        emit_line(indent + "continue;")
+        return declared
+    }
+
     // Bare reassignment: `name = expr`. Always emits a plain C assignment
     // (no `el_val_t` prefix) - by construction the parser only produces
     // Assign for an existing identifier. If the name happens NOT to be in
@@ -1103,6 +1205,10 @@ fn cg_stmt(stmt: Map<String, Any>, indent: String, declared: [String]) -> [Strin
             cg_for_stmt(val, indent, declared)
             return declared
         }
+        if val_kind == "Match" {
+            cg_match_stmt(val, indent, declared)
+            return declared
+        }
         let val_c: String = cg_expr(val)
         emit_line(indent + val_c + ";")
         return declared
@@ -1130,6 +1236,28 @@ fn cg_stmt(stmt: Map<String, Any>, indent: String, declared: [String]) -> [Strin
         return declared
     }
 
+    if kind == "ForRange" {
+        let var_name: String = stmt["var"]
+        let start_expr = stmt["start"]
+        let end_expr = stmt["end"]
+        let inclusive: Bool = stmt["inclusive"]
+        let body = stmt["body"]
+        let start_c: String = cg_expr(start_expr)
+        let end_c: String = cg_expr(end_expr)
+        // Loop variable introduced as a C local scoped to the for statement.
+        // Body gets its own declared clone so let-bindings don't leak out.
+        let body_decl = native_list_clone(declared)
+        let body_decl = native_list_append(body_decl, var_name)
+        if inclusive {
+            emit_line(indent + "for (el_val_t " + var_name + " = " + start_c + "; " + var_name + " <= " + end_c + "; " + var_name + "++) {")
+        } else {
+            emit_line(indent + "for (el_val_t " + var_name + " = " + start_c + "; " + var_name + " < " + end_c + "; " + var_name + "++) {")
+        }
+        cg_stmts(body, indent + "  ", body_decl)
+        emit_line(indent + "}")
+        return declared
+    }
+
     if kind == "FnDef" { return declared }
     if kind == "TypeDef" { return declared }
     if kind == "EnumDef" { return declared }
@@ -1760,6 +1888,12 @@ fn is_int_expr(expr: Map<String, Any>) -> Bool {
             }
             return false
         }
+        if str_eq(op, "Percent") {
+            if is_int_expr(expr["left"]) {
+                if is_int_expr(expr["right"]) { return true }
+            }
+            return false
+        }
         return false
     }
     return false
@@ -1915,6 +2049,9 @@ fn builtin_arity(name: String) -> Int {
     if str_eq(name, "println") { return 1 }
     if str_eq(name, "print") { return 1 }
     if str_eq(name, "readline") { return 0 }
+    // LSP seed primitives
+    if str_eq(name, "__read_n") { return 1 }
+    if str_eq(name, "__print_raw") { return 1 }
     // String
     if str_eq(name, "el_str_concat") { return 2 }
     if str_eq(name, "str_eq") { return 2 }
@@ -1997,6 +2134,84 @@ fn builtin_arity(name: String) -> Int {
     if str_eq(name, "http_post_form_auth") { return 3 }
     if str_eq(name, "http_serve") { return 2 }
     if str_eq(name, "http_set_handler") { return 1 }
+    // Seed primitives (__-prefix) — runtime/el_seed.c
+    if str_eq(name, "__str_len") { return 1 }
+    if str_eq(name, "__str_char_at") { return 2 }
+    if str_eq(name, "__str_alloc") { return 1 }
+    if str_eq(name, "__str_set_char") { return 3 }
+    if str_eq(name, "__str_cmp") { return 2 }
+    if str_eq(name, "__str_ncmp") { return 3 }
+    if str_eq(name, "__str_concat_raw") { return 2 }
+    if str_eq(name, "__str_slice_raw") { return 3 }
+    if str_eq(name, "__int_to_str") { return 1 }
+    if str_eq(name, "__str_to_int") { return 1 }
+    if str_eq(name, "__float_to_str") { return 1 }
+    if str_eq(name, "__str_to_float") { return 1 }
+    if str_eq(name, "__println") { return 1 }
+    if str_eq(name, "__print") { return 1 }
+    if str_eq(name, "__readline") { return 0 }
+    if str_eq(name, "__fs_read") { return 1 }
+    if str_eq(name, "__fs_write") { return 2 }
+    if str_eq(name, "__fs_exists") { return 1 }
+    if str_eq(name, "__fs_list_raw") { return 1 }
+    if str_eq(name, "__fs_mkdir") { return 1 }
+    if str_eq(name, "__fs_write_bytes") { return 3 }
+    if str_eq(name, "__http_do") { return 5 }
+    if str_eq(name, "__http_do_map") { return 5 }
+    if str_eq(name, "__http_do_to_file") { return 5 }
+    if str_eq(name, "__http_serve") { return 2 }
+    if str_eq(name, "__http_serve_v2") { return 2 }
+    if str_eq(name, "__http_response") { return 3 }
+    if str_eq(name, "__thread_create") { return 2 }
+    if str_eq(name, "__thread_join") { return 1 }
+    if str_eq(name, "__mutex_new") { return 0 }
+    if str_eq(name, "__mutex_lock") { return 1 }
+    if str_eq(name, "__mutex_unlock") { return 1 }
+    if str_eq(name, "__exec") { return 1 }
+    if str_eq(name, "__exec_bg") { return 1 }
+    if str_eq(name, "__env_get") { return 1 }
+    if str_eq(name, "__args_json") { return 0 }
+    if str_eq(name, "__exit_program") { return 1 }
+    if str_eq(name, "__time_now_ns") { return 0 }
+    if str_eq(name, "__sleep_ms") { return 1 }
+    if str_eq(name, "__uuid_v4") { return 0 }
+    if str_eq(name, "__sqrt_f") { return 1 }
+    if str_eq(name, "__log_f") { return 1 }
+    if str_eq(name, "__ln_f") { return 1 }
+    if str_eq(name, "__sin_f") { return 1 }
+    if str_eq(name, "__cos_f") { return 1 }
+    if str_eq(name, "__pi_f") { return 0 }
+    if str_eq(name, "__state_set") { return 2 }
+    if str_eq(name, "__state_get") { return 1 }
+    if str_eq(name, "__state_del") { return 1 }
+    if str_eq(name, "__state_keys") { return 0 }
+    if str_eq(name, "__html_sanitize") { return 2 }
+    if str_eq(name, "__url_encode") { return 1 }
+    if str_eq(name, "__url_decode") { return 1 }
+    if str_eq(name, "__json_get") { return 2 }
+    if str_eq(name, "__json_get_raw") { return 2 }
+    if str_eq(name, "__json_parse_map") { return 1 }
+    if str_eq(name, "__json_stringify_val") { return 1 }
+    if str_eq(name, "__json_array_len") { return 1 }
+    if str_eq(name, "__json_array_get") { return 2 }
+    if str_eq(name, "__json_array_get_string") { return 2 }
+    if str_eq(name, "__json_set") { return 3 }
+    if str_eq(name, "__engram_node") { return 3 }
+    if str_eq(name, "__engram_node_full") { return 8 }
+    if str_eq(name, "__engram_get_node") { return 1 }
+    if str_eq(name, "__engram_strengthen") { return 1 }
+    if str_eq(name, "__engram_forget") { return 1 }
+    if str_eq(name, "__engram_node_count") { return 0 }
+    if str_eq(name, "__engram_search") { return 2 }
+    if str_eq(name, "__engram_scan_nodes") { return 2 }
+    if str_eq(name, "__engram_connect") { return 4 }
+    if str_eq(name, "__engram_edge_between") { return 2 }
+    if str_eq(name, "__engram_neighbors") { return 1 }
+    if str_eq(name, "__engram_neighbors_filtered") { return 3 }
+    if str_eq(name, "__engram_activate") { return 2 }
+    if str_eq(name, "__engram_activate_json") { return 2 }
+    if str_eq(name, "__engram_scan_nodes_json") { return 2 }
+    if str_eq(name, "__generate") { return 1 }
     // Filesystem
     if str_eq(name, "fs_read") { return 1 }
     if str_eq(name, "fs_write") { return 2 }
@@ -2049,6 +2264,11 @@ fn builtin_arity(name: String) -> Int {
     if str_eq(name, "bool_to_str") { return 1 }
     // Process
     if str_eq(name, "exit_program") { return 1 }
+    // Subprocess execution
+    if str_eq(name, "exec_command") { return 1 }
+    if str_eq(name, "exec_capture") { return 1 }
+    if str_eq(name, "exec") { return 1 }
+    if str_eq(name, "exec_bg") { return 1 }
     // CGI / DHARMA
     if str_eq(name, "dharma_connect") { return 1 }
     if str_eq(name, "dharma_send") { return 2 }
@@ -2111,6 +2331,18 @@ fn builtin_arity(name: String) -> Int {
     if str_eq(name, "get") { return 2 }
     if str_eq(name, "map_get") { return 2 }
     if str_eq(name, "map_set") { return 3 }
+    // Threading seed primitives
+    if str_eq(name, "__thread_create") { return 2 }
+    if str_eq(name, "__thread_join") { return 1 }
+    if str_eq(name, "__mutex_new") { return 0 }
+    if str_eq(name, "__mutex_lock") { return 1 }
+    if str_eq(name, "__mutex_unlock") { return 1 }
+    // Channel seed primitives
+    if str_eq(name, "__channel_new") { return 1 }
+    if str_eq(name, "__channel_send") { return 2 }
+    if str_eq(name, "__channel_recv") { return 1 }
+    if str_eq(name, "__channel_try_recv") { return 1 }
+    if str_eq(name, "__channel_close") { return 1 }
     // -1 sentinel: variadic / unknown / user-defined -> no check.
     return -1
 }

el-compiler/src/lexer.el

@@ -1,4 +1,4 @@
-// lexer.el — el self-hosting lexer
+// lexer.el - el self-hosting lexer
 //
 // Tokenises an el source string into a list of token maps.
 // Each token is a Map<String, Any> with keys:
@@ -8,9 +8,9 @@
 // Entry point: fn lex(source: String) -> [Map<String, Any>]
 //
 // Uses native_string_chars to split the source into a chars list,
-// then indexes it with native_list_get — avoids O(N²) string cloning.
+// then indexes it with native_list_get - avoids O(N-) string cloning.
 
-// ── Character helpers ─────────────────────────────────────────────────────────
+// -- Character helpers ---------------------------------------------------------
 
 fn lex_is_digit(ch: String) -> Bool {
     if ch == "0" { return true }
@@ -101,7 +101,7 @@ fn make_tok(kind: String, value: String) -> Map<String, Any> {
     { "kind": kind, "value": value }
 }
 
-// ── Keyword lookup ────────────────────────────────────────────────────────────
+// -- Keyword lookup ------------------------------------------------------------
 
 fn keyword_kind(word: String) -> String {
     if word == "let" { return "Let" }
@@ -147,13 +147,15 @@ fn keyword_kind(word: String) -> String {
     if word == "accessor" { return "Accessor" }
     if word == "vessel" { return "Vessel" }
     if word == "extern" { return "Extern" }
+    if word == "break" { return "Break" }
+    if word == "continue" { return "Continue" }
     ""
 }
 
-// ── Scan helpers ──────────────────────────────────────────────────────────────
+// -- Scan helpers --------------------------------------------------------------
 // All scan helpers receive the chars list and total length.
 
-// scan_digits — advance i while chars[i] is a digit
+// scan_digits - advance i while chars[i] is a digit
 // Returns { "text": ..., "pos": i }
 fn scan_digits(chars: [String], start: Int, total: Int) -> Map<String, Any> {
     let i = start
@@ -175,7 +177,7 @@ fn scan_digits(chars: [String], start: Int, total: Int) -> Map<String, Any> {
     { "text": str_join(parts, ""), "pos": i }
 }
 
-// scan_ident — advance i while chars[i] is alphanumeric or underscore
+// scan_ident - advance i while chars[i] is alphanumeric or underscore
 fn scan_ident(chars: [String], start: Int, total: Int) -> Map<String, Any> {
     let i = start
     let parts: [String] = native_list_empty()
@@ -196,14 +198,14 @@ fn scan_ident(chars: [String], start: Int, total: Int) -> Map<String, Any> {
     { "text": str_join(parts, ""), "pos": i }
 }
 
-// ── Code-bearing string detection + comment strip ────────────────────────────
-// Inline JS/CSS literals embedded in El source (e.g. <script>…</script> blobs
+// -- Code-bearing string detection + comment strip ----------------------------
+// Inline JS/CSS literals embedded in El source (e.g. <script>-</script> blobs
 // or stylesheet payloads inside string literals) carry their own line and
 // block comments. Those comments leak into the served HTML and reveal build
 // notes the visitor should never see. We strip them at the lexer so every
 // downstream consumer (codegen-c, codegen-js, parser) gets the cleaned form.
 //
-// looks_like_code — heuristic gate so we only strip strings that actually
+// looks_like_code - heuristic gate so we only strip strings that actually
 // embed JS or CSS. Plain prose, hex blobs, JSON, etc. pass through verbatim.
 
 fn substr_at(chars: [String], start: Int, total: Int, needle: String) -> Bool {
@@ -245,7 +247,7 @@ fn looks_like_code(s: String) -> Bool {
     false
 }
 
-// strip_code_comments — character-by-character walk. Tracks JS string state
+// strip_code_comments - character-by-character walk. Tracks JS string state
 // (single, double, backtick) and never strips inside one. Backslash escapes
 // inside JS strings consume the next char verbatim. URLs like https:// are
 // preserved by checking the previous char before treating // as a line
@@ -398,7 +400,7 @@ fn strip_code_comments(s: String) -> String {
     str_join(out_parts, "")
 }
 
-// scan_string — scan a quoted string literal, handling \" escapes.
+// scan_string - scan a quoted string literal, handling \" escapes.
 // Starts AFTER the opening quote. Returns { "text": content, "pos": i_after_close }
 fn scan_string(chars: [String], start: Int, total: Int) -> Map<String, Any> {
     let i = start
@@ -458,7 +460,239 @@ fn scan_string(chars: [String], start: Int, total: Int) -> Map<String, Any> {
     { "text": str_join(parts, ""), "pos": i }
 }
 
-// ── Main lexer ────────────────────────────────────────────────────────────────
+// -- String interpolation ------------------------------------------------------
+//
+// scan_interp_brace - scan from `start` (the char after `${`) to the matching
+// `}`, tracking brace depth so inner braces (e.g. fn calls, map literals) are
+// handled correctly. Returns { "text": inner_source, "pos": i_after_close }.
+fn scan_interp_brace(chars: [String], start: Int, total: Int) -> Map<String, Any> {
+    let i = start
+    let parts: [String] = native_list_empty()
+    let depth = 1
+    let running = true
+    while running {
+        if i >= total {
+            let running = false
+        } else {
+            let ch: String = native_list_get(chars, i)
+            if ch == "{" {
+                let depth = depth + 1
+                let parts = native_list_append(parts, ch)
+                let i = i + 1
+            } else {
+                if ch == "}" {
+                    let depth = depth - 1
+                    if depth <= 0 {
+                        // Closing brace of the interpolation - stop, do not include it
+                        let i = i + 1
+                        let running = false
+                    } else {
+                        let parts = native_list_append(parts, ch)
+                        let i = i + 1
+                    }
+                } else {
+                    let parts = native_list_append(parts, ch)
+                    let i = i + 1
+                }
+            }
+        }
+    }
+    { "text": str_join(parts, ""), "pos": i }
+}
+
+// interp_tokens_append_all - copy every token from src into dst, skipping the
+// trailing Eof sentinel that lex() always appends. Returns the updated dst list.
+fn interp_tokens_append_all(dst: [Map<String, Any>], src: [Map<String, Any>]) -> [Map<String, Any>] {
+    let src_len: Int = native_list_len(src)
+    let j = 0
+    let result = dst
+    while j < src_len {
+        let tok: Map<String, Any> = native_list_get(src, j)
+        let tk: String = tok["kind"]
+        if tk == "Eof" {
+            let j = src_len
+        } else {
+            let result = native_list_append(result, tok)
+            let j = j + 1
+        }
+    }
+    result
+}
+
+// scan_interp_string - scan a string literal that may contain ${expr}
+// interpolations. Starts AFTER the opening `"`.
+// Returns { "tokens": [token list to inject], "pos": i_after_close_quote }.
+//
+// For a plain string (no ${}) this emits a single Str token, identical to the
+// old scan_string path. For an interpolated string it emits a flat sequence
+// of tokens equivalent to the string-concat expression, for example:
+//
+//   "hello ${name}!"
+//   => Str("hello ") Plus <tokens for name> Plus Str("!")
+//
+// Empty literal segments between adjacent ${ } blocks are omitted. The
+// resulting token stream is consumed by the existing parse_binop / parse_primary
+// path in the parser with zero parser changes required.
+//
+// Supported escape sequences: \" \n \t \r \\ \$ (literal dollar sign).
+// Nested quotes inside ${} are not supported; use a variable instead.
+fn scan_interp_string(chars: [String], start: Int, total: Int) -> Map<String, Any> {
+    let i = start
+    let out_tokens: [Map<String, Any>] = native_list_empty()
+    let cur_part: [String] = native_list_empty()
+    let has_interp = false
+    let need_plus = false
+    let running = true
+
+    while running {
+        if i >= total {
+            let running = false
+        } else {
+            let ch: String = native_list_get(chars, i)
+
+            if ch == "\\" {
+                // Escape sequence
+                let next_i = i + 1
+                if next_i < total {
+                    let next_ch: String = native_list_get(chars, next_i)
+                    if next_ch == "$" {
+                        // \$ => literal '$' (escape for interpolation syntax)
+                        let cur_part = native_list_append(cur_part, "$")
+                        let i = next_i + 1
+                    } else {
+                        if next_ch == "\"" {
+                            let cur_part = native_list_append(cur_part, "\"")
+                            let i = next_i + 1
+                        } else {
+                            if next_ch == "n" {
+                                let cur_part = native_list_append(cur_part, "\n")
+                                let i = next_i + 1
+                            } else {
+                                if next_ch == "t" {
+                                    let cur_part = native_list_append(cur_part, "\t")
+                                    let i = next_i + 1
+                                } else {
+                                    if next_ch == "r" {
+                                        let cur_part = native_list_append(cur_part, "\r")
+                                        let i = next_i + 1
+                                    } else {
+                                        if next_ch == "\\" {
+                                            let cur_part = native_list_append(cur_part, "\\")
+                                            let i = next_i + 1
+                                        } else {
+                                            let cur_part = native_list_append(cur_part, next_ch)
+                                            let i = next_i + 1
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    let i = i + 1
+                }
+            } else {
+                if ch == "\"" {
+                    // Closing quote - stop scanning
+                    let i = i + 1
+                    let running = false
+                } else {
+                    if ch == "$" {
+                        // Check for ${ (start of interpolation)
+                        let next_i = i + 1
+                        let is_interp = false
+                        if next_i < total {
+                            let next_ch: String = native_list_get(chars, next_i)
+                            if next_ch == "{" {
+                                let is_interp = true
+                            }
+                        }
+                        if is_interp {
+                            // Flush the accumulated literal part (if non-empty)
+                            let part_len: Int = native_list_len(cur_part)
+                            if part_len > 0 {
+                                let part_text = str_join(cur_part, "")
+                                if need_plus {
+                                    let out_tokens = native_list_append(out_tokens, make_tok("Plus", "+"))
+                                }
+                                let clean_part = part_text
+                                if looks_like_code(part_text) {
+                                    let clean_part = strip_code_comments(part_text)
+                                }
+                                let out_tokens = native_list_append(out_tokens, make_tok("Str", clean_part))
+                                let need_plus = true
+                            }
+                            let cur_part = native_list_empty()
+                            let has_interp = true
+
+                            // Scan brace-balanced expression source
+                            let brace_result = scan_interp_brace(chars, next_i + 1, total)
+                            let expr_src: String = brace_result["text"]
+                            let new_i: Int = brace_result["pos"]
+                            let i = new_i
+
+                            // Re-lex the expression and inline the tokens.
+                            // Wrap in ( ) so that operators inside ${} (e.g.
+                            // age + 1) are parsed as a grouped sub-expression
+                            // rather than merging with the surrounding concat
+                            // Plus tokens at the wrong precedence level.
+                            let inner_toks: [Map<String, Any>] = lex(expr_src)
+                            let inner_len: Int = native_list_len(inner_toks)
+
+                            if need_plus {
+                                let out_tokens = native_list_append(out_tokens, make_tok("Plus", "+"))
+                            }
+                            // Empty interpolation ${} => empty string segment
+                            if inner_len <= 1 {
+                                let out_tokens = native_list_append(out_tokens, make_tok("Str", ""))
+                            } else {
+                                let out_tokens = native_list_append(out_tokens, make_tok("LParen", "("))
+                                let out_tokens = interp_tokens_append_all(out_tokens, inner_toks)
+                                let out_tokens = native_list_append(out_tokens, make_tok("RParen", ")"))
+                            }
+                            let need_plus = true
+                        } else {
+                            // Plain '$' not followed by '{' - treat as literal
+                            let cur_part = native_list_append(cur_part, "$")
+                            let i = i + 1
+                        }
+                    } else {
+                        let cur_part = native_list_append(cur_part, ch)
+                        let i = i + 1
+                    }
+                }
+            }
+        }
+    }
+
+    // Flush remaining literal segment and build final token list
+    let part_text = str_join(cur_part, "")
+    let part_len: Int = native_list_len(cur_part)
+    if has_interp {
+        // Interpolated string: only emit trailing segment if non-empty
+        if part_len > 0 {
+            let clean_part = part_text
+            if looks_like_code(part_text) {
+                let clean_part = strip_code_comments(part_text)
+            }
+            if need_plus {
+                let out_tokens = native_list_append(out_tokens, make_tok("Plus", "+"))
+            }
+            let out_tokens = native_list_append(out_tokens, make_tok("Str", clean_part))
+        }
+    } else {
+        // Plain string with no interpolation - same behaviour as old scan_string
+        let clean_text = part_text
+        if looks_like_code(part_text) {
+            let clean_text = strip_code_comments(part_text)
+        }
+        let out_tokens = native_list_append(out_tokens, make_tok("Str", clean_text))
+    }
+
+    { "tokens": out_tokens, "pos": i }
+}
+
+// -- Main lexer ----------------------------------------------------------------
 
 fn lex(source: String) -> [Map<String, Any>] {
     let chars: [String] = native_string_chars(source)
@@ -503,20 +737,16 @@ fn lex(source: String) -> [Map<String, Any>] {
                     let i = i + 1
                 }
             } else {
-                // String literal
+                // String literal (plain or interpolated with ${expr} syntax).
+                // scan_interp_string handles both cases: plain strings emit a
+                // single Str token; interpolated strings emit a flat token
+                // sequence (Str Plus expr-tokens Plus Str ...) that the parser
+                // naturally assembles into a BinOp concat tree.
                 if ch == "\"" {
-                    let result = scan_string(chars, i + 1, total)
-                    let str_text: String = result["text"]
-                    let new_pos: Int = result["pos"]
-                    // Compile-time scrub: strings that embed JS or CSS get
-                    // their // line comments and /* block comments stripped
-                    // before the token reaches the parser. Plain prose passes
-                    // through untouched.
-                    let clean_text = str_text
-                    if looks_like_code(str_text) {
-                        let clean_text = strip_code_comments(str_text)
-                    }
-                    let tokens = native_list_append(tokens, make_tok("Str", clean_text))
+                    let interp_result = scan_interp_string(chars, i + 1, total)
+                    let interp_toks: [Map<String, Any>] = interp_result["tokens"]
+                    let new_pos: Int = interp_result["pos"]
+                    let tokens = interp_tokens_append_all(tokens, interp_toks)
                     let i = new_pos
                 } else {
                     // Number literal
@@ -696,8 +926,24 @@ fn lex(source: String) -> [Map<String, Any>] {
                                                                                                 let i = i + 1
                                                                                             } else {
                                                                                                 if ch == "." {
-                                                                                                    let tokens = native_list_append(tokens, make_tok("Dot", "."))
-                                                                                                    let i = i + 1
+                                                                                                    // Check for ..= (inclusive range) before .. (exclusive range) before single .
+                                                                                                    let peek2_i = i + 2
+                                                                                                    let peek2_ch = ""
+                                                                                                    if peek2_i < total {
+                                                                                                        let peek2_ch: String = native_list_get(chars, peek2_i)
+                                                                                                    }
+                                                                                                    if peek_ch == "." {
+                                                                                                        if peek2_ch == "=" {
+                                                                                                            let tokens = native_list_append(tokens, make_tok("DotDotEq", "..="))
+                                                                                                            let i = i + 3
+                                                                                                        } else {
+                                                                                                            let tokens = native_list_append(tokens, make_tok("DotDot", ".."))
+                                                                                                            let i = i + 2
+                                                                                                        }
+                                                                                                    } else {
+                                                                                                        let tokens = native_list_append(tokens, make_tok("Dot", "."))
+                                                                                                        let i = i + 1
+                                                                                                    }
                                                                                                 } else {
                                                                                                     if ch == ";" {
                                                                                                         let tokens = native_list_append(tokens, make_tok("Semicolon", ";"))
@@ -711,7 +957,7 @@ fn lex(source: String) -> [Map<String, Any>] {
                                                                                                                 let tokens = native_list_append(tokens, make_tok("QuestionMark", "?"))
                                                                                                                 let i = i + 1
                                                                                                             } else {
-                                                                                                                // unknown char — skip
+                                                                                                                // unknown char - skip
                                                                                                                 let i = i + 1
                                                                                                             }
                                                                                                         }

el-compiler/src/parser.el

@@ -1,4 +1,4 @@
-// parser.el — el self-hosting recursive descent parser
+// parser.el - el self-hosting recursive descent parser
 //
 // Consumes the token list produced by lexer.el and builds a list of AST
 // statement maps.  Each statement and expression is a Map<String, Any>.
@@ -11,7 +11,7 @@
 //
 // Entry point: fn parse(tokens: [Map<String, Any>]) -> [Map<String, Any>]
 
-// ── Token access helpers ──────────────────────────────────────────────────────
+// -- Token access helpers ------------------------------------------------------
 
 fn tok_at(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     native_list_get(tokens, pos)
@@ -36,13 +36,13 @@ fn expect(tokens: [Map<String, Any>], pos: Int, kind: String) -> Int {
     pos + 1
 }
 
-// ── Result helpers ────────────────────────────────────────────────────────────
+// -- Result helpers ------------------------------------------------------------
 
 fn make_result(node: Map<String, Any>, pos: Int) -> Map<String, Any> {
     { "node": node, "pos": pos }
 }
 
-// ── Type annotation parser ────────────────────────────────────────────────────
+// -- Type annotation parser ----------------------------------------------------
 // Skips over a type annotation, returning the new position.
 // Types can be: Ident, [Type], Map<K,V>, Type?, Type<Type,...>
 
@@ -100,8 +100,8 @@ fn skip_type(tokens: [Map<String, Any>], pos: Int) -> Int {
     pos + 1
 }
 
-// ── Parameter list ────────────────────────────────────────────────────────────
-// Parses (name: Type, name: Type, ...) — returns { "params": [...], "pos": ... }
+// -- Parameter list ------------------------------------------------------------
+// Parses (name: Type, name: Type, ...) - returns { "params": [...], "pos": ... }
 
 fn parse_params(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     let p = expect(tokens, pos, "LParen")
@@ -140,7 +140,7 @@ fn parse_params(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     { "params": params, "pos": p }
 }
 
-// ── Expression parsing ────────────────────────────────────────────────────────
+// -- Expression parsing --------------------------------------------------------
 
 fn parse_primary(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     let k = tok_kind(tokens, pos)
@@ -212,14 +212,14 @@ fn parse_primary(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     //
     // Suppression: when parse_if / parse_while / parse_for / parse_match
     // are parsing a head expression, they set __no_block_expr=1 so a stray
-    // `{` here doesn't get gobbled as a Map literal — it belongs to the
+    // `{` here doesn't get gobbled as a Map literal - it belongs to the
     // following block. Without this, `if a || b { ... }` could mis-parse
     // (the `||` recursion lands at `{` and tries to read the if-body as a
     // Map, then loops forever when keys don't match `Str: expr`).
     if k == "LBrace" {
         let no_block: String = state_get("__no_block_expr")
         if str_eq(no_block, "1") {
-            // Fall through to fallback — caller will see `{` and treat it
+            // Fall through to fallback - caller will see `{` and treat it
             // as the start of the block they're expecting.
             return make_result({ "expr": "Nil" }, pos)
         }
@@ -300,7 +300,7 @@ fn parse_primary(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     // token kinds for the deploy/retry DSLs, but they're also valid as
     // parameter names and local variables. When one of these appears in
     // expression position (where only an Ident makes sense), treat it as
-    // an Ident carrying the original text — otherwise references to a
+    // an Ident carrying the original text - otherwise references to a
     // parameter named `target` compile to EL_NULL.
     if k == "Target" { return make_result({ "expr": "Ident", "name": v }, pos + 1) }
     if k == "To" { return make_result({ "expr": "Ident", "name": v }, pos + 1) }
@@ -472,9 +472,9 @@ fn parse_block(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     { "stmts": stmts, "pos": p }
 }
 
-// ── Postfix expressions (calls, field access, index) ─────────────────────────
+// -- Postfix expressions (calls, field access, index) -------------------------
 
-// is_duration_unit — recognise the postfix unit suffix on a numeric literal.
+// is_duration_unit - recognise the postfix unit suffix on a numeric literal.
 // Used by parse_postfix to detect `30.seconds`-shape time literals before
 // falling back to the generic `obj.field` field-access lowering. Singular
 // and plural forms map to the same nanosecond multiplier; codegen does the
@@ -578,7 +578,7 @@ fn parse_postfix(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     make_result(node, p)
 }
 
-// ── Binary expression precedence climbing ────────────────────────────────────
+// -- Binary expression precedence climbing ------------------------------------
 
 fn op_precedence(kind: String) -> Int {
     if kind == "Or" { return 1 }
@@ -593,6 +593,7 @@ fn op_precedence(kind: String) -> Int {
     if kind == "Minus" { return 5 }
     if kind == "Star" { return 6 }
     if kind == "Slash" { return 6 }
+    if kind == "Percent" { return 6 }
     0
 }
 
@@ -609,6 +610,7 @@ fn is_binop(kind: String) -> Bool {
     if kind == "Minus" { return true }
     if kind == "Star" { return true }
     if kind == "Slash" { return true }
+    if kind == "Percent" { return true }
     false
 }
 
@@ -641,7 +643,7 @@ fn parse_expr(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     parse_binop(tokens, pos, 1)
 }
 
-// ── Statement parsing ─────────────────────────────────────────────────────────
+// -- Statement parsing ---------------------------------------------------------
 
 fn parse_stmt(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     let k = tok_kind(tokens, pos)
@@ -653,7 +655,7 @@ fn parse_stmt(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
         let p = p + 1
         let ltype = ""
         let k2 = tok_kind(tokens, p)
-        // optional type annotation: name: Type — capture the leading
+        // optional type annotation: name: Type - capture the leading
         // identifier so codegen can dispatch arithmetic vs concat on
         // `+` between two typed Idents.
         if k2 == "Colon" {
@@ -687,7 +689,7 @@ fn parse_stmt(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
         return make_result({ "stmt": "Return", "value": val }, p)
     }
 
-    // extern fn declaration (no body — forward declaration for separate compilation)
+    // extern fn declaration (no body - forward declaration for separate compilation)
     if k == "Extern" {
         let p = pos + 1
         let k2: String = tok_kind(tokens, p)
@@ -858,7 +860,17 @@ fn parse_stmt(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
         return make_result({ "stmt": "While", "cond": cond, "body": body }, p)
     }
 
-    // for loop
+    // break statement
+    if k == "Break" {
+        return make_result({ "stmt": "Break" }, pos + 1)
+    }
+
+    // continue statement
+    if k == "Continue" {
+        return make_result({ "stmt": "Continue" }, pos + 1)
+    }
+
+    // for loop (range or list iteration)
     if k == "For" {
         let p = pos + 1
         let item_name = tok_value(tokens, p)
@@ -868,15 +880,41 @@ fn parse_stmt(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
         state_set("__no_block_expr", "1")
         let r = parse_expr(tokens, p)
         state_set("__no_block_expr", prev_no_block)
-        let list_expr = r["node"]
+        let start_expr = r["node"]
         let p = r["pos"]
+        // Check for range operator: .. (exclusive) or ..= (inclusive)
+        let range_k = tok_kind(tokens, p)
+        if range_k == "DotDot" {
+            // exclusive range: for i in start..end
+            let p = p + 1
+            let r2 = parse_expr(tokens, p)
+            let end_expr = r2["node"]
+            let p = r2["pos"]
+            let r3 = parse_block(tokens, p)
+            let body = r3["stmts"]
+            let p = r3["pos"]
+            return make_result({ "stmt": "ForRange", "var": item_name, "start": start_expr, "end": end_expr, "inclusive": false, "body": body }, p)
+        }
+        if range_k == "DotDotEq" {
+            // inclusive range: for i in start..=end
+            let p = p + 1
+            let r2 = parse_expr(tokens, p)
+            let end_expr = r2["node"]
+            let p = r2["pos"]
+            let r3 = parse_block(tokens, p)
+            let body = r3["stmts"]
+            let p = r3["pos"]
+            return make_result({ "stmt": "ForRange", "var": item_name, "start": start_expr, "end": end_expr, "inclusive": true, "body": body }, p)
+        }
+        // No range operator: regular for-in (list iteration)
+        let list_expr = start_expr
         let r2 = parse_block(tokens, p)
         let body = r2["stmts"]
         let p = r2["pos"]
         return make_result({ "stmt": "For", "item": item_name, "list": list_expr, "body": body }, p)
     }
 
-    // @decorator — capture decorator name and attach to following stmt
+    // @decorator - capture decorator name and attach to following stmt
     if k == "At" {
         let p = pos + 1
         let dec_name = tok_value(tokens, p)
@@ -1039,7 +1077,7 @@ fn parse_stmt(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
     make_result({ "stmt": "Expr", "value": val }, p)
 }
 
-// ── Top-level parse ────────────────────────────────────────────────────────────
+// -- Top-level parse ------------------------------------------------------------
 
 fn parse(tokens: [Map<String, Any>]) -> [Map<String, Any>] {
     let total: Int = native_list_len(tokens)
@@ -1058,7 +1096,7 @@ fn parse(tokens: [Map<String, Any>]) -> [Map<String, Any>] {
                 let stmt = r["node"]
                 let new_pos: Int = r["pos"]
                 let stmts = native_list_append(stmts, stmt)
-                // Guard against infinite loops — if pos didn't advance, force it
+                // Guard against infinite loops - if pos didn't advance, force it
                 if new_pos <= pos {
                     let pos = pos + 1
                 } else {

elb.el

@@ -1,4 +1,4 @@
-// elb.el — El Build Coordinator
+// elb.el - El Build Coordinator
 //
 // The build system for El programs. Written in El. Builds El.
 //
@@ -16,11 +16,11 @@
 //   3. For each file: if .el is newer than .elh/.c, compile with elc --emit-header
 //   4. Link all .c files + el_runtime.c into the final binary
 //
-// Each module compiles independently — no 128K-line blobs.
+// Each module compiles independently - no 128K-line blobs.
 // Downstream compilations read .elh headers (function signatures only),
 // not source. Incremental: only recompile what changed.
 
-// ── Flags ─────────────────────────────────────────────────────────────────────
+// -- Flags ---------------------------------------------------------------------
 
 fn flag_bool(argv: [String], name: String) -> Bool {
     let n: Int = native_list_len(argv)
@@ -47,7 +47,7 @@ fn flag_val(argv: [String], name: String, default_val: String) -> String {
     return default_val
 }
 
-// ── Manifest parsing ──────────────────────────────────────────────────────────
+// -- Manifest parsing ----------------------------------------------------------
 //
 // Read the entry file from manifest.el:
 //   build { entry "soul.el" }
@@ -100,7 +100,7 @@ fn parse_manifest_name(src: String) -> String {
     return "out"
 }
 
-// ── Path helpers ───────────────────────────────────────────────────────────────
+// -- Path helpers ---------------------------------------------------------------
 
 fn dirname_of(path: String) -> String {
     let n: Int = str_len(path)
@@ -148,14 +148,14 @@ fn file_is_newer(a: String, b: String) -> Bool {
     let cmd: String = "test -f " + b + " && test " + a + " -nt " + b + " && echo yes || echo no"
     let result: String = str_trim(exec_capture(cmd))
     if str_eq(result, "yes") { return true }
-    // b doesn't exist — check with test -f
+    // b doesn't exist - check with test -f
     let exist_cmd: String = "test -f " + b + " && echo exists || echo missing"
     let exist: String = str_trim(exec_capture(exist_cmd))
     if str_eq(exist, "missing") { return true }
     return false
 }
 
-// ── Import graph walker ────────────────────────────────────────────────────────
+// -- Import graph walker --------------------------------------------------------
 //
 // Walk import statements in each .el file to build the dependency graph.
 // Returns a list of absolute paths in topological order (deps before dependents).
@@ -219,7 +219,7 @@ fn walk_imports(src_path: String, visited: [String], order: [String]) -> Map<Str
     return { "visited": visited, "order": order }
 }
 
-// ── Build ──────────────────────────────────────────────────────────────────────
+// -- Build ----------------------------------------------------------------------
 
 fn compile_module(src_path: String, out_dir: String, elc_bin: String, dry_run: Bool, verbose: Bool) -> Bool {
     let bname: String = basename_noext(src_path)
@@ -246,13 +246,23 @@ fn compile_module(src_path: String, out_dir: String, elc_bin: String, dry_run: B
         println("elb: compile failed: " + src_path)
         return false
     }
+
+    // Move the generated .elh (written next to the source by elc) into
+    // out_dir so that #include "module.elh" lines in the generated .c
+    // files resolve correctly when cc is invoked with -I <out_dir>.
+    let src_elh: String = path_with_ext(src_path, ".elh")
+    let mv_cmd: String = "cp " + src_elh + " " + elh_out + " 2>/dev/null || true"
+    exec_command(mv_cmd)
+
     return true
 }
 
-fn link_binary(c_files: [String], out_bin: String, runtime_path: String, dry_run: Bool) -> Bool {
+fn link_binary(c_files: [String], out_bin: String, runtime_path: String, out_dir: String, dry_run: Bool) -> Bool {
     let n: Int = native_list_len(c_files)
     let parts: [String] = native_list_empty()
-    let parts = native_list_append(parts, "cc -O2 -I " + dirname_of(runtime_path))
+    // Include both the runtime dir (for el_runtime.h) and the output dir
+    // (for module.elh cross-module forward declarations).
+    let parts = native_list_append(parts, "cc -O2 -fbracket-depth=1024 -I " + dirname_of(runtime_path) + " -I " + out_dir)
     let i = 0
     while i < n {
         let f: String = native_list_get(c_files, i)
@@ -260,7 +270,7 @@ fn link_binary(c_files: [String], out_bin: String, runtime_path: String, dry_run
         let i = i + 1
     }
     let parts = native_list_append(parts, runtime_path)
-    let parts = native_list_append(parts, "-lcurl -lpthread")
+    let parts = native_list_append(parts, "-lcurl -lpthread -lm")
     let parts = native_list_append(parts, "-o " + out_bin)
     let cmd: String = str_join(parts, " ")
     println("  link     " + out_bin)
@@ -273,7 +283,7 @@ fn link_binary(c_files: [String], out_bin: String, runtime_path: String, dry_run
     return true
 }
 
-// ── Main ───────────────────────────────────────────────────────────────────────
+// -- Main -----------------------------------------------------------------------
 
 fn main() -> Void {
     let argv: [String] = args()
@@ -311,7 +321,7 @@ fn main() -> Void {
         }
     }
     if str_eq(runtime_path, "") {
-        println("elb: cannot locate el_runtime.c — use --runtime=PATH")
+        println("elb: cannot locate el_runtime.c - use --runtime=PATH")
         exit(1)
     }
 
@@ -359,11 +369,11 @@ fn main() -> Void {
 
     // Link
     let out_bin: String = out_dir + "/" + pkg_name
-    let linked: Bool = link_binary(c_files, out_bin, runtime_path, dry_run)
+    let linked: Bool = link_binary(c_files, out_bin, runtime_path, out_dir, dry_run)
     if !linked {
         println("elb: link failed")
         exit(1)
     }
 
-    println("elb: done → " + out_bin)
+    println("elb: done -> " + out_bin)
 }

epm/manifest.el

@@ -0,0 +1,17 @@
+// epm — El Package Manager
+//
+// Manages vessels: publish, install, resolve dependencies.
+// Vessels are stored in Engram as nodes. epm reads the local manifest.el,
+// talks to Engram over HTTP, and writes installed vessels to .epm/vessels/.
+
+package "epm" {
+    version "0.1.0"
+    description "El Package Manager — vessel registry, publish, install, resolve"
+    authors ["Will Anderson <will@neurontechnologies.ai>"]
+    edition "2026"
+}
+
+build {
+    entry "src/epm.el"
+    output "dist/"
+}

epm/src/epm.el

@@ -0,0 +1,213 @@
+// epm/src/epm.el — El Package Manager entry point
+//
+// epm manages vessels: the deployable, versioned units of El code.
+// Vessels are stored in Engram (the graph database) and installed locally
+// under .epm/vessels/.
+//
+// Usage:
+//   epm publish                   # publish current project to registry
+//   epm install                   # install all dependencies from manifest.el
+//   epm install <vessel>          # install a specific vessel
+//   epm list                      # list all vessels in the registry
+//   epm info <vessel>             # show metadata for a vessel
+//   epm info <vessel> <version>   # show metadata for a specific version
+//
+// Configuration (environment):
+//   ENGRAM_URL   — Engram base URL (default: http://localhost:8742)
+//
+// Import order: manifest.el, registry.el, install.el must be compiled first.
+// This file imports all three and is the build entry point.
+
+import "manifest.el"
+import "registry.el"
+import "install.el"
+
+// ── Subcommand handlers ───────────────────────────────────────────────────────
+
+// cmd_publish reads manifest.el from the current directory and publishes
+// the vessel/package to the Engram registry.
+fn cmd_publish() -> Void {
+    let src: String = fs_read("manifest.el")
+    if str_eq(src, "") {
+        println("epm: no manifest.el found in current directory")
+        exit(1)
+    }
+
+    let name: String = manifest_name(src)
+    if str_eq(name, "") {
+        println("epm: manifest.el has no 'vessel' or 'package' declaration")
+        exit(1)
+    }
+
+    let version: String = manifest_version(src)
+    if str_eq(version, "") {
+        println("epm: manifest.el has no 'version' declaration")
+        exit(1)
+    }
+
+    let description: String = manifest_description(src)
+    let entry: String       = manifest_entry(src)
+    let deps_json: String   = manifest_deps(src)
+
+    println("epm: publishing " + name + " " + version + " ...")
+
+    let node_id: String = registry_publish(name, version, description, entry, deps_json)
+    if str_eq(node_id, "") {
+        println("epm: publish failed")
+        exit(1)
+    }
+
+    println("epm: published " + name + " " + version + " (node: " + node_id + ")")
+}
+
+// cmd_install_named installs a specific vessel by name (with optional version).
+// Expects: install <name> or install <name>@<version>
+fn cmd_install_named(spec: String) -> Void {
+    // spec may be "el-auth" or "el-auth@0.1.0"
+    let at: Int = str_index_of(spec, "@")
+    let vname: String = spec
+    let vver: String  = ""
+    if at > 0 {
+        let vname = str_slice(spec, 0, at)
+        let vver  = str_slice(spec, at + 1, str_len(spec))
+    }
+
+    println("epm: installing " + vname + " ...")
+
+    let mk1: Int = exec_command("mkdir -p .epm/vessels")
+    let ok: Bool = install_vessel(vname, vver)
+    if !ok {
+        println("epm: install failed")
+        exit(1)
+    }
+}
+
+// cmd_list prints all vessels registered in Engram.
+fn cmd_list() -> Void {
+    println("epm: fetching vessel list from registry ...")
+    let raw: String = registry_list()
+    let n: Int = json_array_len(raw)
+
+    if n == 0 {
+        println("epm: no vessels found in registry")
+        return
+    }
+
+    println("epm: " + native_int_to_str(n) + " vessel(s) in registry:")
+    println("")
+
+    let i: Int = 0
+    while i < n {
+        // Each element is a quoted+escaped content JSON blob
+        let elem: String    = json_array_get_string(raw, i)
+        let vname: String   = json_get_string(elem, "name")
+        let vver: String    = json_get_string(elem, "version")
+        let vdesc: String   = json_get_string(elem, "description")
+        println("  " + vname + " " + vver + "  — " + vdesc)
+        let i = i + 1
+    }
+}
+
+// cmd_info prints detailed metadata for a specific vessel.
+// argv is the full args list; idx is the position of the vessel name.
+fn cmd_info(argv: [String], idx: Int) -> Void {
+    let argc: Int = native_list_len(argv)
+    if idx >= argc {
+        println("epm: usage: epm info <vessel> [version]")
+        exit(1)
+    }
+
+    let vname: String = native_list_get(argv, idx)
+    let vver: String  = ""
+    if idx + 1 < argc {
+        let vver = native_list_get(argv, idx + 1)
+    }
+
+    let content: String = registry_find(vname, vver)
+    if str_eq(content, "") {
+        println("epm: vessel '" + vname + "' not found in registry")
+        exit(1)
+    }
+
+    let name: String   = json_get_string(content, "name")
+    let ver: String    = json_get_string(content, "version")
+    let desc: String   = json_get_string(content, "description")
+    let entry: String  = json_get_string(content, "entry")
+    let deps_raw: String = json_get_raw(content, "deps")
+
+    println("name:        " + name)
+    println("version:     " + ver)
+    println("description: " + desc)
+    println("entry:       " + entry)
+
+    let dep_n: Int = json_array_len(deps_raw)
+    if dep_n == 0 {
+        println("dependencies: (none)")
+    } else {
+        println("dependencies:")
+        let di: Int = 0
+        while di < dep_n {
+            let dep: String      = json_array_get(deps_raw, di)
+            let dep_name: String = json_get_string(dep, "name")
+            let dep_ver: String  = json_get_string(dep, "version")
+            println("  " + dep_name + " " + dep_ver)
+            let di = di + 1
+        }
+    }
+}
+
+// ── Main ──────────────────────────────────────────────────────────────────────
+
+fn main() -> Void {
+    let argv: [String] = args()
+    let argc: Int = native_list_len(argv)
+
+    // argv[0] is the program name; subcommand is argv[1]
+    if argc < 2 {
+        println("epm — El Package Manager")
+        println("")
+        println("usage:")
+        println("  epm publish                  publish current project to registry")
+        println("  epm install                  install all dependencies (from manifest.el)")
+        println("  epm install <vessel>         install a specific vessel")
+        println("  epm install <vessel>@<ver>   install a specific vessel at a version")
+        println("  epm list                     list all vessels in the registry")
+        println("  epm info <vessel>            show vessel metadata")
+        println("  epm info <vessel> <version>  show metadata for a specific version")
+        println("")
+        println("configuration:")
+        println("  ENGRAM_URL   Engram base URL (default: http://localhost:8742)")
+        exit(0)
+    }
+
+    let sub: String = native_list_get(argv, 1)
+
+    if str_eq(sub, "publish") {
+        cmd_publish()
+        return
+    }
+
+    if str_eq(sub, "install") {
+        if argc >= 3 {
+            let spec: String = native_list_get(argv, 2)
+            cmd_install_named(spec)
+        } else {
+            cmd_install()
+        }
+        return
+    }
+
+    if str_eq(sub, "list") {
+        cmd_list()
+        return
+    }
+
+    if str_eq(sub, "info") {
+        cmd_info(argv, 2)
+        return
+    }
+
+    println("epm: unknown subcommand '" + sub + "'")
+    println("run 'epm' with no arguments for usage")
+    exit(1)
+}

epm/src/install.el

@@ -0,0 +1,226 @@
+// epm/src/install.el — dependency resolution and vessel installation
+//
+// Reads the current project's manifest.el, walks the full dependency graph
+// by fetching each dep from Engram, detects cycles, and produces a
+// topological install order (dependencies before dependents).
+//
+// Installed vessels land in: .epm/vessels/<name>/
+//
+// Cycle detection: each recursion carries a chain of names currently on
+// the call stack. If a dep already appears in the chain it's a cycle.
+//
+// Algorithm:
+//   1. Parse manifest.el to get direct deps
+//   2. For each dep, fetch its manifest from Engram
+//   3. Recurse into that dep's own deps (depth-first)
+//   4. Append dep to order after all its transitive deps
+//   5. Deduplicate: skip already-ordered vessels
+
+// ── List helpers (operating on String lists) ──────────────────────────────────
+
+// list_contains returns true if item appears in lst.
+fn list_contains(lst: [String], item: String) -> Bool {
+    let n: Int = native_list_len(lst)
+    let i: Int = 0
+    while i < n {
+        let v: String = native_list_get(lst, i)
+        if str_eq(v, item) { return true }
+        let i = i + 1
+    }
+    return false
+}
+
+// ── Dependency graph walker ───────────────────────────────────────────────────
+
+// resolve_deps_recursive fetches a vessel's metadata from Engram and walks
+// its dependency list depth-first, building a topological order.
+//
+// Parameters:
+//   name     — vessel name to resolve
+//   version  — version string (may be "" for any)
+//   chain    — names currently on the recursion stack (cycle detection)
+//   visited  — names already appended to order (dedup)
+//   order    — accumulated result (list of "name:version" strings)
+//
+// Returns a Map with keys "visited", "order", and "ok" (Bool as String).
+fn resolve_deps_recursive(name: String, version: String, chain: [String], visited: [String], order: [String]) -> Map<String, Any> {
+    let key: String = name + ":" + version
+
+    // Skip if already ordered
+    if list_contains(visited, key) {
+        return { "visited": visited, "order": order, "ok": "true" }
+    }
+
+    // Cycle detection: if name is already in the call chain, it's a cycle
+    if list_contains(chain, name) {
+        println("epm: error: dependency cycle detected involving '" + name + "'")
+        return { "visited": visited, "order": order, "ok": "false" }
+    }
+
+    // Push this name onto the cycle-detection chain
+    let chain = native_list_append(chain, name)
+
+    // Fetch vessel metadata from Engram
+    let content: String = registry_find(name, version)
+    if str_eq(content, "") {
+        println("epm: error: vessel '" + name + "' version '" + version + "' not found in registry")
+        return { "visited": visited, "order": order, "ok": "false" }
+    }
+
+    // content is a JSON blob: {"name":..., "version":..., "deps":[...]}
+    let actual_version: String = json_get_string(content, "version")
+    let actual_key: String = name + ":" + actual_version
+    let deps_json: String = json_get_raw(content, "deps")
+
+    // Walk this vessel's dependencies first (depth-first)
+    let dep_count: Int = json_array_len(deps_json)
+    let di: Int = 0
+    while di < dep_count {
+        let dep: String    = json_array_get(deps_json, di)
+        let dep_name: String  = json_get_string(dep, "name")
+        let dep_ver: String   = json_get_string(dep, "version")
+
+        let r = resolve_deps_recursive(dep_name, dep_ver, chain, visited, order)
+        let ok_str: String = r["ok"]
+        if str_eq(ok_str, "false") {
+            return r
+        }
+        let visited = r["visited"]
+        let order   = r["order"]
+
+        let di = di + 1
+    }
+
+    // Now append this vessel (after all its deps)
+    let visited = native_list_append(visited, actual_key)
+    let order   = native_list_append(order, actual_key)
+
+    return { "visited": visited, "order": order, "ok": "true" }
+}
+
+// ── Install order ─────────────────────────────────────────────────────────────
+
+// resolve_install_order reads manifest.el from the current directory and
+// returns a list of "name:version" strings in topological install order.
+//
+// Returns an empty list on failure (error is printed to stdout).
+fn resolve_install_order() -> [String] {
+    let src: String = fs_read("manifest.el")
+    if str_eq(src, "") {
+        println("epm: no manifest.el found in current directory")
+        return native_list_empty()
+    }
+
+    let deps_json: String = manifest_deps(src)
+    let dep_count: Int = json_array_len(deps_json)
+    if dep_count == 0 {
+        println("epm: no dependencies declared in manifest.el")
+        return native_list_empty()
+    }
+
+    let chain: [String]   = native_list_empty()
+    let visited: [String] = native_list_empty()
+    let order: [String]   = native_list_empty()
+
+    let i: Int = 0
+    while i < dep_count {
+        let dep: String      = json_array_get(deps_json, i)
+        let dep_name: String = json_get_string(dep, "name")
+        let dep_ver: String  = json_get_string(dep, "version")
+
+        let r = resolve_deps_recursive(dep_name, dep_ver, chain, visited, order)
+        let ok_str: String = r["ok"]
+        if str_eq(ok_str, "false") {
+            return native_list_empty()
+        }
+        let visited = r["visited"]
+        let order   = r["order"]
+
+        let i = i + 1
+    }
+
+    return order
+}
+
+// ── Installation ──────────────────────────────────────────────────────────────
+
+// install_vessel fetches a vessel's source from Engram and writes it
+// to .epm/vessels/<name>/.
+//
+// Currently writes the content JSON blob as a manifest record so that
+// other tools can introspect what is installed. When Engram stores actual
+// source archives, this function would extract them.
+//
+// Returns true on success.
+fn install_vessel(name: String, version: String) -> Bool {
+    let content: String = registry_find(name, version)
+    if str_eq(content, "") {
+        println("epm: error: cannot fetch '" + name + "' '" + version + "' from registry")
+        return false
+    }
+
+    let install_dir: String = ".epm/vessels/" + name
+    let mkdir_ret: Int = exec_command("mkdir -p " + install_dir)
+
+    // Write the content blob as installed.json so downstream tools know what's there
+    let dest: String = install_dir + "/installed.json"
+    fs_write(dest, content)
+
+    println("epm: installed " + name + " " + version + " -> " + dest)
+    return true
+}
+
+// ── Top-level install ─────────────────────────────────────────────────────────
+
+// cmd_install resolves and installs all dependencies for the current project.
+fn cmd_install() -> Void {
+    let src: String = fs_read("manifest.el")
+    if str_eq(src, "") {
+        println("epm: no manifest.el found in current directory")
+        exit(1)
+    }
+
+    let pkg_name: String = manifest_name(src)
+    println("epm: resolving dependencies for " + pkg_name)
+
+    let order: [String] = resolve_install_order()
+    let n: Int = native_list_len(order)
+
+    if n == 0 {
+        println("epm: nothing to install")
+        return
+    }
+
+    println("epm: install order (" + native_int_to_str(n) + " vessels):")
+    let i: Int = 0
+    while i < n {
+        let entry: String = native_list_get(order, i)
+        println("  " + entry)
+        let i = i + 1
+    }
+
+    // Ensure .epm directory exists
+    let mk2: Int = exec_command("mkdir -p .epm/vessels")
+
+    // Install each vessel in topological order
+    let j: Int = 0
+    while j < n {
+        let kv: String = native_list_get(order, j)
+        // Split "name:version" on the last colon
+        let colon: Int = str_index_of(kv, ":")
+        if colon < 0 {
+            println("epm: error: malformed order entry: " + kv)
+            exit(1)
+        }
+        let vname: String   = str_slice(kv, 0, colon)
+        let vver: String    = str_slice(kv, colon + 1, str_len(kv))
+        let ok: Bool = install_vessel(vname, vver)
+        if !ok {
+            println("epm: install failed at " + kv)
+            exit(1)
+        }
+        let j = j + 1
+    }
+
+    println("epm: all dependencies installed")
+}

epm/src/manifest.el

@@ -0,0 +1,175 @@
+// epm/src/manifest.el — vessel and package manifest parser
+//
+// Parses manifest.el files in the vessel/package format:
+//
+//   vessel "el-auth" {
+//       version "0.1.0"
+//       description "..."
+//       authors ["..."]
+//       edition "2026"
+//   }
+//
+//   dependencies {
+//       el-platform "1.0"
+//       el-identity "0.1"
+//   }
+//
+//   build {
+//       entry "src/main.el"
+//       output "dist/"
+//   }
+//
+// Parsing is line-by-line string extraction, same approach as elb.el.
+// No AST, no grammar — sufficient for well-formed manifests.
+
+// ── String extraction helpers ─────────────────────────────────────────────────
+
+// extract_quoted extracts the first double-quoted token from a string.
+// Returns "" if no quoted token is found.
+// Example: extract_quoted("vessel \"el-auth\" {") -> "el-auth"
+fn extract_quoted(s: String) -> String {
+    let first: Int = str_index_of(s, "\"")
+    if first < 0 { return "" }
+    let after: String = str_slice(s, first + 1, str_len(s))
+    let close: Int = str_index_of(after, "\"")
+    if close < 0 { return "" }
+    return str_slice(after, 0, close)
+}
+
+// ── Manifest field extraction ─────────────────────────────────────────────────
+
+// manifest_name extracts the vessel or package name from manifest source.
+// Recognises both "vessel" and "package" block headers.
+fn manifest_name(src: String) -> String {
+    let lines: [String] = str_split(src, "\n")
+    let n: Int = native_list_len(lines)
+    let i: Int = 0
+    while i < n {
+        let line: String = native_list_get(lines, i)
+        let t: String = str_trim(line)
+        if str_starts_with(t, "vessel ") {
+            return extract_quoted(t)
+        }
+        if str_starts_with(t, "package ") {
+            return extract_quoted(t)
+        }
+        let i = i + 1
+    }
+    return ""
+}
+
+// manifest_version extracts the version string from manifest source.
+fn manifest_version(src: String) -> String {
+    let lines: [String] = str_split(src, "\n")
+    let n: Int = native_list_len(lines)
+    let i: Int = 0
+    while i < n {
+        let line: String = native_list_get(lines, i)
+        let t: String = str_trim(line)
+        if str_starts_with(t, "version ") {
+            return extract_quoted(t)
+        }
+        let i = i + 1
+    }
+    return ""
+}
+
+// manifest_description extracts the description string from manifest source.
+fn manifest_description(src: String) -> String {
+    let lines: [String] = str_split(src, "\n")
+    let n: Int = native_list_len(lines)
+    let i: Int = 0
+    while i < n {
+        let line: String = native_list_get(lines, i)
+        let t: String = str_trim(line)
+        if str_starts_with(t, "description ") {
+            return extract_quoted(t)
+        }
+        let i = i + 1
+    }
+    return ""
+}
+
+// manifest_entry extracts the build entry file from manifest source.
+fn manifest_entry(src: String) -> String {
+    let lines: [String] = str_split(src, "\n")
+    let n: Int = native_list_len(lines)
+    let i: Int = 0
+    while i < n {
+        let line: String = native_list_get(lines, i)
+        let t: String = str_trim(line)
+        if str_starts_with(t, "entry ") {
+            return extract_quoted(t)
+        }
+        let i = i + 1
+    }
+    return ""
+}
+
+// manifest_deps extracts dependencies as a JSON array of {"name":..., "version":...} objects.
+//
+// Scans lines inside the dependencies { ... } block.
+// Each dep line looks like:
+//   el-platform "1.0"
+//
+// Returns a JSON array string, e.g.:
+//   [{"name":"el-platform","version":"1.0"},{"name":"el-identity","version":"0.1"}]
+fn manifest_deps(src: String) -> String {
+    let lines: [String] = str_split(src, "\n")
+    let n: Int = native_list_len(lines)
+    let in_deps: Bool = false
+    let result: String = "["
+    let count: Int = 0
+    let i: Int = 0
+    while i < n {
+        let line: String = native_list_get(lines, i)
+        let t: String = str_trim(line)
+
+        // Detect entry into dependencies block
+        if str_eq(t, "dependencies {") {
+            let in_deps = true
+            let i = i + 1
+        } else {
+            if in_deps {
+                // Detect exit from block
+                if str_eq(t, "}") {
+                    let in_deps = false
+                } else {
+                    // Each dep line: name "version"
+                    // Find first space to split name from quoted version
+                    let sp: Int = str_index_of(t, " ")
+                    if sp > 0 {
+                        let dep_name: String = str_slice(t, 0, sp)
+                        let rest: String = str_trim(str_slice(t, sp, str_len(t)))
+                        let dep_ver: String = extract_quoted(rest)
+                        if !str_eq(dep_name, "") {
+                            let entry: String = "{\"name\":\"" + dep_name + "\",\"version\":\"" + dep_ver + "\"}"
+                            if count == 0 {
+                                let result = result + entry
+                            } else {
+                                let result = result + "," + entry
+                            }
+                            let count = count + 1
+                        }
+                    }
+                }
+            }
+            let i = i + 1
+        }
+    }
+    return result + "]"
+}
+
+// manifest_is_vessel returns true if the manifest declares a vessel (not a package).
+fn manifest_is_vessel(src: String) -> Bool {
+    let lines: [String] = str_split(src, "\n")
+    let n: Int = native_list_len(lines)
+    let i: Int = 0
+    while i < n {
+        let line: String = native_list_get(lines, i)
+        let t: String = str_trim(line)
+        if str_starts_with(t, "vessel ") { return true }
+        let i = i + 1
+    }
+    return false
+}

epm/src/registry.el

@@ -0,0 +1,170 @@
+// epm/src/registry.el — Engram-backed vessel registry
+//
+// Vessels are stored in Engram as nodes with a structured label scheme:
+//
+//   label:     "vessel:<name>:<version>"   (used as the search key)
+//   content:   JSON blob with full vessel metadata
+//   node_type: "Entity"
+//   salience:  0.9  (vessels are high-salience, long-lived knowledge)
+//
+// All registry operations go over HTTP to Engram. The Engram URL is read
+// from the ENGRAM_URL environment variable; defaults to http://localhost:8742.
+//
+// Endpoints used:
+//   POST /api/nodes          — publish a vessel node
+//   GET  /api/search?q=...   — find vessels by label prefix
+
+// ── Engram URL ────────────────────────────────────────────────────────────────
+
+// registry_url returns the base URL for Engram, with no trailing slash.
+fn registry_url() -> String {
+    let u: String = config("ENGRAM_URL")
+    if str_eq(u, "") { return "http://localhost:8742" }
+    // Strip trailing slash if present
+    let n: Int = str_len(u)
+    if str_ends_with(u, "/") {
+        return str_slice(u, 0, n - 1)
+    }
+    return u
+}
+
+// ── Publish ───────────────────────────────────────────────────────────────────
+
+// registry_publish stores a vessel node in Engram.
+//
+// Parameters:
+//   name        — vessel name (e.g. "el-auth")
+//   version     — semver string (e.g. "0.1.0")
+//   description — human-readable description
+//   entry       — build entry file path
+//   deps_json   — JSON array of dep objects (from manifest_deps)
+//
+// Returns the created node ID on success, "" on failure.
+fn registry_publish(name: String, version: String, description: String, entry: String, deps_json: String) -> String {
+    let label: String = "vessel:" + name + ":" + version
+
+    // Build the content JSON — all vessel metadata in one blob
+    let esc_name: String = json_escape_string(name)
+    let esc_ver: String  = json_escape_string(version)
+    let esc_desc: String = json_escape_string(description)
+    let esc_entry: String = json_escape_string(entry)
+    let content_json: String = "{\"name\":\"" + esc_name + "\",\"version\":\"" + esc_ver + "\",\"description\":\"" + esc_desc + "\",\"entry\":\"" + esc_entry + "\",\"deps\":" + deps_json + "}"
+
+    // Escape the content blob for embedding in the outer JSON
+    let esc_label: String = json_escape_string(label)
+    let esc_content: String = json_escape_string(content_json)
+
+    let body: String = "{\"label\":\"" + esc_label + "\",\"content\":\"" + esc_content + "\",\"node_type\":\"Entity\",\"salience\":0.9}"
+    let url: String  = registry_url() + "/api/nodes"
+
+    let resp: String = http_post_json(url, body)
+    if str_eq(resp, "") {
+        println("epm: error: Engram unreachable at " + url)
+        return ""
+    }
+
+    // Check for error in response
+    let err: String = json_get_string(resp, "error")
+    if !str_eq(err, "") {
+        println("epm: error from Engram: " + err)
+        return ""
+    }
+
+    let node_id: String = json_get_string(resp, "id")
+    return node_id
+}
+
+// ── Find ──────────────────────────────────────────────────────────────────────
+
+// registry_find searches Engram for a specific vessel by name and version.
+//
+// Returns the content JSON blob for the vessel, or "" if not found.
+// When version is "" any version matching the name is accepted (first hit).
+fn registry_find(name: String, version: String) -> String {
+    let query: String = "vessel:" + name
+    if !str_eq(version, "") {
+        let query = "vessel:" + name + ":" + version
+    }
+
+    let enc_q: String = url_encode(query)
+    let url: String = registry_url() + "/api/search?q=" + enc_q + "&limit=10"
+
+    let resp: String = http_get(url)
+    if str_eq(resp, "") {
+        println("epm: error: Engram unreachable at " + registry_url())
+        return ""
+    }
+
+    // Response is a JSON array of node objects
+    let count: Int = json_array_len(resp)
+    if count == 0 { return "" }
+
+    // Walk results to find exact match
+    let i: Int = 0
+    while i < count {
+        let node: String = json_array_get(resp, i)
+        let node_label: String = json_get_string(node, "label")
+        let expected_label: String = "vessel:" + name
+        if !str_eq(version, "") {
+            let expected_label = "vessel:" + name + ":" + version
+        }
+        if str_eq(node_label, expected_label) {
+            // The content field is an escaped JSON blob — decode it
+            let raw_content: String = json_get_string(node, "content")
+            return raw_content
+        }
+        let i = i + 1
+    }
+
+    // No exact match; if version was unspecified return first result's content
+    if str_eq(version, "") {
+        let first: String = json_array_get(resp, 0)
+        let first_label: String = json_get_string(first, "label")
+        if str_starts_with(first_label, "vessel:" + name + ":") {
+            return json_get_string(first, "content")
+        }
+    }
+
+    return ""
+}
+
+// ── List ──────────────────────────────────────────────────────────────────────
+
+// registry_list returns all vessels from Engram as a JSON array.
+//
+// Each element in the returned array is a content JSON blob.
+// Returns "[]" when no vessels are found or Engram is unreachable.
+fn registry_list() -> String {
+    let enc_q: String = url_encode("vessel:")
+    let url: String = registry_url() + "/api/search?q=" + enc_q + "&limit=200"
+
+    let resp: String = http_get(url)
+    if str_eq(resp, "") {
+        println("epm: error: Engram unreachable at " + registry_url())
+        return "[]"
+    }
+
+    let count: Int = json_array_len(resp)
+    if count == 0 { return "[]" }
+
+    // Collect content blobs for nodes whose label starts with "vessel:"
+    let out: String = "["
+    let added: Int = 0
+    let i: Int = 0
+    while i < count {
+        let node: String = json_array_get(resp, i)
+        let lbl: String  = json_get_string(node, "label")
+        if str_starts_with(lbl, "vessel:") {
+            let content: String = json_get_string(node, "content")
+            let esc: String = json_escape_string(content)
+            if added == 0 {
+                let out = out + "\"" + esc + "\""
+            } else {
+                let out = out + ",\"" + esc + "\""
+            }
+            let added = added + 1
+        }
+        let i = i + 1
+    }
+    return out + "]"
+}

releases/v1.0.0-20260501/el_runtime.h

@@ -199,6 +199,19 @@ el_val_t  http_get_to_file(el_val_t url, el_val_t headers_map, el_val_t output_p
 el_val_t  url_encode(el_val_t s);   /* RFC 3986 unreserved set */
 el_val_t  url_decode(el_val_t s);   /* '+' → space, %XX → byte  */
 
+/* ── HTML allowlist sanitizer ────────────────────────────────────────────────
+ * el_html_sanitize(input_html, allowlist_json) — strict allowlist HTML
+ * cleaner. State-machine parser; tag/attribute names compared case-
+ * insensitively against the allowlist; `<a href>` / `<… src>` URL schemes
+ * validated (http, https, mailto, fragment-only, or relative); whole-
+ * subtree drop for script / style / iframe / object / embed / form; HTML-
+ * escapes free text outside dropped subtrees.
+ *
+ * The allowlist is JSON of the form
+ *     {"p":[],"a":["href","title"],"strong":[],...}
+ * where each value is the array of attribute names allowed for that tag. */
+el_val_t  el_html_sanitize(el_val_t input_html, el_val_t allowlist_json);
+
 /* ── Filesystem ──────────────────────────────────────────────────────────── */
 
 el_val_t  fs_read(el_val_t path);
@@ -246,6 +259,146 @@ el_val_t  time_from_parts(el_val_t secs, el_val_t ns, el_val_t tz);
 el_val_t  time_add(el_val_t ts, el_val_t n, el_val_t unit);
 el_val_t  time_diff(el_val_t ts1, el_val_t ts2, el_val_t unit);
 
+/* ── Instant + Duration: first-class temporal types ──────────────────────────
+ * Both types share the el_val_t (int64) slot. Instants are nanoseconds
+ * since the Unix epoch; Durations are signed nanoseconds. Type discipline
+ * is enforced at codegen-time: BinOps on names registered as Instant or
+ * Duration route through the typed wrappers below; mismatches like
+ * Instant+Instant become #error at the C compiler.
+ *
+ * Postfix literals — `30.seconds`, `1.hour`, `500.millis`, `30.nanos` — are
+ * recognised by the parser as DurationLit AST nodes and lowered to literal
+ * int64 nanoseconds at codegen time. The runtime never sees the units. */
+
+el_val_t  el_now_instant(void);
+el_val_t  now(void);
+el_val_t  unix_seconds(el_val_t n);
+el_val_t  unix_millis(el_val_t n);
+el_val_t  instant_from_iso8601(el_val_t s);
+
+el_val_t  el_duration_from_nanos(el_val_t ns);
+el_val_t  duration_seconds(el_val_t n);
+el_val_t  duration_millis(el_val_t n);
+el_val_t  duration_nanos(el_val_t n);
+
+el_val_t  el_instant_add_dur(el_val_t inst, el_val_t dur);
+el_val_t  el_instant_sub_dur(el_val_t inst, el_val_t dur);
+el_val_t  el_instant_diff(el_val_t a, el_val_t b);
+el_val_t  el_duration_add(el_val_t a, el_val_t b);
+el_val_t  el_duration_sub(el_val_t a, el_val_t b);
+el_val_t  el_duration_scale(el_val_t dur, el_val_t scalar);
+el_val_t  el_duration_div(el_val_t dur, el_val_t scalar);
+
+el_val_t  el_instant_lt(el_val_t a, el_val_t b);
+el_val_t  el_instant_le(el_val_t a, el_val_t b);
+el_val_t  el_instant_gt(el_val_t a, el_val_t b);
+el_val_t  el_instant_ge(el_val_t a, el_val_t b);
+el_val_t  el_instant_eq(el_val_t a, el_val_t b);
+el_val_t  el_instant_ne(el_val_t a, el_val_t b);
+el_val_t  el_duration_lt(el_val_t a, el_val_t b);
+el_val_t  el_duration_le(el_val_t a, el_val_t b);
+el_val_t  el_duration_gt(el_val_t a, el_val_t b);
+el_val_t  el_duration_ge(el_val_t a, el_val_t b);
+el_val_t  el_duration_eq(el_val_t a, el_val_t b);
+el_val_t  el_duration_ne(el_val_t a, el_val_t b);
+
+el_val_t  instant_to_unix_seconds(el_val_t i);
+el_val_t  instant_to_unix_millis(el_val_t i);
+el_val_t  instant_to_iso8601(el_val_t i);
+el_val_t  duration_to_seconds(el_val_t d);
+el_val_t  duration_to_millis(el_val_t d);
+el_val_t  duration_to_nanos(el_val_t d);
+
+el_val_t  el_sleep_duration(el_val_t dur);
+el_val_t  unix_timestamp(void);
+
+el_val_t  ttl_cache_set(el_val_t key, el_val_t value);
+el_val_t  ttl_cache_get(el_val_t key, el_val_t max_age);
+el_val_t  ttl_cache_age(el_val_t key);
+
+/* ── Calendar + CalendarTime + Rhythm + LocalDate/Time/DateTime ─────────────
+ * Phase 1.5 of the time system. Calendar is pluggable: EarthCalendar (IANA
+ * zones, Gregorian, DST) is the user-facing default; MarsCalendar,
+ * CycleCalendar(period), NoCycleCalendar, RelativeCalendar handle non-Earth
+ * domains.
+ *
+ * A Calendar interprets an Instant under a particular cycle convention and
+ * produces a CalendarTime. CalendarTime carries the underlying Instant and
+ * a back-pointer to its Calendar; arithmetic and formatting consult the
+ * Calendar to convert ns since epoch into year/month/day/hour/minute/second
+ * (or sol/phase, or cycle/phase, depending on kind).
+ *
+ * Storage convention: Calendar / CalendarTime / Rhythm / LocalDate /
+ * LocalDateTime are heap-allocated structs whose pointers are cast into
+ * el_val_t. A 24-bit magic header at offset 0 lets the runtime identify
+ * the kind safely. LocalTime is small enough to live in the int64 slot
+ * directly (nanos since midnight, signed).                                  */
+
+/* Zone — opaque IANA zone or fixed offset, used by EarthCalendar.
+ * `zone_id` is either an IANA name ("America/New_York", "UTC") or a fixed
+ * offset string ("+05:30", "-08:00"). The runtime resolves it via tzset()
+ * on first use of the owning EarthCalendar.                                  */
+el_val_t  zone(el_val_t id);
+el_val_t  zone_utc(void);
+el_val_t  zone_local(void);
+el_val_t  zone_offset(el_val_t hours, el_val_t minutes);
+
+/* Calendar constructors. Each returns an el_val_t pointer to a heap-
+ * allocated, magic-tagged Calendar struct. Calendars are interned by
+ * (kind, zone_id, period_ns, epoch_ns) so identical constructors return
+ * the same pointer — equality is reference equality.                        */
+el_val_t  earth_calendar(el_val_t z);
+el_val_t  earth_calendar_default(void);
+el_val_t  mars_calendar(void);
+el_val_t  cycle_calendar(el_val_t period_dur);
+el_val_t  no_cycle_calendar(void);
+el_val_t  relative_calendar(el_val_t epoch_inst);
+
+/* CalendarTime constructors and methods. Returns a heap-allocated struct
+ * whose pointer fits in el_val_t. */
+el_val_t  now_in(el_val_t cal);
+el_val_t  in_calendar(el_val_t inst, el_val_t cal);
+el_val_t  cal_format(el_val_t ct, el_val_t pattern);
+el_val_t  cal_to_instant(el_val_t ct);
+el_val_t  cal_cycle_phase(el_val_t ct);
+el_val_t  cal_in(el_val_t ct, el_val_t cal);
+
+/* LocalDate / LocalTime / LocalDateTime — calendar-agnostic value types.
+ * LocalTime carries nanoseconds since midnight as a signed int64 directly
+ * in the el_val_t slot (no allocation). LocalDate / LocalDateTime are
+ * heap-allocated structs with magic headers. */
+el_val_t  local_date(el_val_t y, el_val_t m, el_val_t d);
+el_val_t  local_time(el_val_t h, el_val_t m, el_val_t s, el_val_t ns);
+el_val_t  local_datetime(el_val_t date, el_val_t time);
+el_val_t  zoned(el_val_t date, el_val_t time, el_val_t cal);
+
+el_val_t  local_date_year(el_val_t ld);
+el_val_t  local_date_month(el_val_t ld);
+el_val_t  local_date_day(el_val_t ld);
+el_val_t  local_time_hour(el_val_t lt);
+el_val_t  local_time_minute(el_val_t lt);
+el_val_t  local_time_second(el_val_t lt);
+el_val_t  local_time_nanos(el_val_t lt);
+
+el_val_t  el_local_date_add_dur(el_val_t ld, el_val_t dur);
+el_val_t  el_local_time_add_dur(el_val_t lt, el_val_t dur);
+el_val_t  el_local_date_lt(el_val_t a, el_val_t b);
+el_val_t  el_local_date_eq(el_val_t a, el_val_t b);
+
+/* Rhythm — pluggable recurrence AST. Returns a heap-allocated struct
+ * pointer in el_val_t; rhythms are immutable so callers may share them. */
+el_val_t  rhythm_cycle_start(void);
+el_val_t  rhythm_cycle_phase(el_val_t phase);
+el_val_t  rhythm_duration(el_val_t d);
+el_val_t  rhythm_session_start(void);
+el_val_t  rhythm_event(el_val_t name);
+el_val_t  rhythm_and(el_val_t a, el_val_t b);
+el_val_t  rhythm_or(el_val_t a, el_val_t b);
+el_val_t  rhythm_weekday(el_val_t day);
+el_val_t  rhythm_weekly_at(el_val_t day, el_val_t hour, el_val_t minute);
+el_val_t  rhythm_next_after(el_val_t r, el_val_t after, el_val_t cal);
+el_val_t  rhythm_matches(el_val_t r, el_val_t ct);
+
 /* ── UUID ────────────────────────────────────────────────────────────────── */
 
 el_val_t  uuid_new(void);
@@ -288,10 +441,53 @@ el_val_t  str_char_at(el_val_t s, el_val_t i);
 el_val_t  str_char_code(el_val_t s, el_val_t i);
 el_val_t  str_pad_left(el_val_t s, el_val_t width, el_val_t pad);
 el_val_t  str_pad_right(el_val_t s, el_val_t width, el_val_t pad);
-el_val_t  str_format(el_val_t template, el_val_t data);
+el_val_t  str_format(el_val_t fmt, el_val_t data);
 el_val_t  str_lower(el_val_t s);
 el_val_t  str_upper(el_val_t s);
 
+/* ── Text-processing primitives (Phase 1: byte/codepoint, ASCII char classes)
+ * Phase 2 (filed): Unicode-grapheme awareness, NFC/NFD normalization, regex.
+ * is_* predicates: empty input returns false; multi-char requires ALL bytes
+ * to match. ASCII ranges only in Phase 1. */
+
+/* Counting */
+el_val_t  str_count(el_val_t s, el_val_t sub);              /* non-overlapping */
+el_val_t  str_count_chars(el_val_t s);                      /* codepoint count */
+el_val_t  str_count_bytes(el_val_t s);                      /* alias of str_len */
+el_val_t  str_count_lines(el_val_t s);
+el_val_t  str_count_words(el_val_t s);
+el_val_t  str_count_letters(el_val_t s);                    /* ASCII [A-Za-z] */
+el_val_t  str_count_digits(el_val_t s);                     /* ASCII [0-9] */
+
+/* Find / position */
+el_val_t  str_index_of_all(el_val_t s, el_val_t sub);       /* [Int] of byte offsets */
+el_val_t  str_last_index_of(el_val_t s, el_val_t sub);
+el_val_t  str_find_chars(el_val_t s, el_val_t any_of);      /* first idx of any ch */
+
+/* Transform */
+el_val_t  str_repeat(el_val_t s, el_val_t n);
+el_val_t  str_reverse(el_val_t s);                          /* by codepoint */
+el_val_t  str_strip_prefix(el_val_t s, el_val_t prefix);
+el_val_t  str_strip_suffix(el_val_t s, el_val_t suffix);
+el_val_t  str_strip_chars(el_val_t s, el_val_t chars);
+el_val_t  str_lstrip(el_val_t s);
+el_val_t  str_rstrip(el_val_t s);
+
+/* Char classification (Bool) */
+el_val_t  is_letter(el_val_t s);
+el_val_t  is_digit(el_val_t s);
+el_val_t  is_alphanumeric(el_val_t s);
+el_val_t  is_whitespace(el_val_t s);
+el_val_t  is_punctuation(el_val_t s);
+el_val_t  is_uppercase(el_val_t s);
+el_val_t  is_lowercase(el_val_t s);
+
+/* Split / join */
+el_val_t  str_split_lines(el_val_t s);
+el_val_t  str_split_chars(el_val_t s);                      /* alias of native_string_chars */
+el_val_t  str_split_n(el_val_t s, el_val_t sep, el_val_t n);
+el_val_t  str_join(el_val_t list, el_val_t sep);            /* alias of list_join */
+
 /* ── List additions ──────────────────────────────────────────────────────── */
 
 el_val_t  list_push(el_val_t list, el_val_t elem);
@@ -364,6 +560,19 @@ el_val_t  engram_node(el_val_t content, el_val_t node_type, el_val_t salience);
 el_val_t  engram_node_full(el_val_t content, el_val_t node_type, el_val_t label,
                            el_val_t salience, el_val_t importance, el_val_t confidence,
                            el_val_t tier, el_val_t tags);
+/* Layered consciousness — see el_runtime.c for the layered architecture
+ * design notes (search "Layered consciousness architecture"). The five
+ * canonical layers (safety / core-identity / domain-knowledge / imprint /
+ * suit) are seeded automatically; engram_add_layer extends the registry
+ * with imprint or suit overlays at runtime. Nodes default to layer 1
+ * (core-identity) when created via engram_node / engram_node_full. */
+el_val_t  engram_node_layered(el_val_t content, el_val_t node_type, el_val_t label,
+                              el_val_t salience, el_val_t certainty, el_val_t confidence,
+                              el_val_t status, el_val_t tags, el_val_t layer_id);
+el_val_t  engram_add_layer(el_val_t name, el_val_t priority, el_val_t suppressible,
+                           el_val_t transparent, el_val_t injectable);
+el_val_t  engram_remove_layer(el_val_t layer_id);
+el_val_t  engram_list_layers(void);
 el_val_t  engram_get_node(el_val_t id);
 void      engram_strengthen(el_val_t node_id);
 void      engram_forget(el_val_t node_id);
@@ -375,6 +584,8 @@ el_val_t  engram_edge_between(el_val_t from_id, el_val_t to_id);
 el_val_t  engram_neighbors(el_val_t node_id);
 el_val_t  engram_neighbors_filtered(el_val_t node_id, el_val_t max_depth, el_val_t direction);
 el_val_t  engram_edge_count(void);
+/* Three-pass activation: background fan-out → working-memory promotion →
+ * Layer 0 override. See "Three-pass activation" in el_runtime.c. */
 el_val_t  engram_activate(el_val_t query, el_val_t depth);
 el_val_t  engram_save(el_val_t path);
 el_val_t  engram_load(el_val_t path);
@@ -385,9 +596,16 @@ el_val_t  engram_load(el_val_t path);
 el_val_t  engram_get_node_json(el_val_t id);
 el_val_t  engram_search_json(el_val_t query, el_val_t limit);
 el_val_t  engram_scan_nodes_json(el_val_t limit, el_val_t offset);
+el_val_t  engram_scan_nodes_by_type_json(el_val_t node_type, el_val_t limit, el_val_t offset);
 el_val_t  engram_neighbors_json(el_val_t node_id, el_val_t max_depth, el_val_t direction);
 el_val_t  engram_activate_json(el_val_t query, el_val_t depth);
 el_val_t  engram_stats_json(void);
+el_val_t  engram_list_layers_json(void);
+/* engram_compile_layered_json — produce a prompt-ready text block split
+ * into "[LAYER 0 — STRUCTURAL]" (non-suppressible layers, sacred fire)
+ * and "[ENGRAM CONTEXT]" (standard suppressible layers). Returns "" if
+ * no nodes promoted to working memory. */
+el_val_t  engram_compile_layered_json(el_val_t intent, el_val_t depth);
 
 /* ── LLM (Anthropic API client) ─────────────────────────────────────────────
  * All functions call https://api.anthropic.com/v1/messages with the API key
@@ -476,6 +694,21 @@ el_val_t  pq_hybrid_handshake(el_val_t remote_pub_combined);
 
 el_val_t  sha3_256_hex(el_val_t input);
 
+/* ── AEAD: AES-256-GCM (libcrypto-backed) ───────────────────────────────────
+ * Symmetric authenticated encryption used to wrap envelopes after a KEM
+ * handshake. Caller MUST supply a 32-byte key (64 hex chars) — typically the
+ * Kyber-768 / hybrid shared_secret, optionally normalized via SHA3-256.
+ *
+ * aead_encrypt returns a JSON map {"nonce":"...","ciphertext":"..."} where
+ * ciphertext is the AES-256-GCM output with the 16-byte auth tag appended.
+ * Nonce is a fresh 12-byte CSPRNG draw — callers never pick the nonce, which
+ * structurally rules out the GCM nonce-reuse footgun.
+ *
+ * aead_decrypt returns the plaintext String, or "" on any failure (including
+ * auth-tag mismatch). Callers MUST check for "" before trusting the result. */
+el_val_t  aead_encrypt(el_val_t key_hex, el_val_t plaintext);
+el_val_t  aead_decrypt(el_val_t key_hex, el_val_t nonce_hex, el_val_t ciphertext_hex);
+
 /* ── Native VM builtin aliases (for compiled El source) ─────────────────────
  * These match the El VM's native_* builtins so that El source compiled
  * to C can call the same names without modification.                */
@@ -502,6 +735,22 @@ el_val_t  get(el_val_t list, el_val_t index);      /* el_list_get    */
 el_val_t  map_get(el_val_t map, el_val_t key);     /* el_map_get     */
 el_val_t  map_set(el_val_t map, el_val_t key, el_val_t value); /* el_map_set */
 
+/* ── OTLP/HTTP Observability ─────────────────────────────────────────────── */
+/* See bottom of el_runtime.c for the implementation.
+ * Configured by env vars OTLP_ENDPOINT, OTEL_SERVICE_NAME, OTEL_SERVICE_VERSION.
+ * No-op when OTLP_ENDPOINT is unset. Drop-on-failure semantics. */
+/* ── Subprocess execution ────────────────────────────────────────────────── */
+el_val_t exec_command(el_val_t cmd);   /* run shell command, return exit code */
+el_val_t exec_capture(el_val_t cmd);   /* run shell command, capture stdout   */
+el_val_t exec(el_val_t cmd);           /* exec(cmd) → stdout String (30s timeout) */
+el_val_t exec_bg(el_val_t cmd);        /* exec_bg(cmd) → PID String (non-blocking) */
+
+el_val_t emit_log(el_val_t level, el_val_t msg, el_val_t fields_json);
+el_val_t emit_metric(el_val_t name, el_val_t value, el_val_t tags_json);
+el_val_t trace_span_start(el_val_t name);
+el_val_t trace_span_end(el_val_t span_handle);
+el_val_t emit_event(el_val_t name, el_val_t duration_ms);
+
 #ifdef __cplusplus
 }
 #endif

runtime/channel.el

@@ -0,0 +1,164 @@
+// channel.el — Go-style channels for El
+//
+// Channels are the communication primitive for concurrent El programs.
+// Threads send values into a channel; other threads receive them.
+// Channels are typed by convention — all values are Strings.
+//
+// Backed by four seed primitives in el_runtime.c:
+//   __channel_new(capacity)   -> Int    create channel; cap=0 = unbounded
+//   __channel_send(ch, msg)             push msg; blocks if bounded and full
+//   __channel_recv(ch)        -> String pop msg; blocks until available; "" on close
+//   __channel_try_recv(ch)    -> String non-blocking pop; "" if empty
+//   __channel_close(ch)                 mark closed; wake all blocked recvers
+//
+// Usage:
+//   let ch: Int = channel_new(10)   // buffered channel, capacity 10
+//   spawn("producer", int_to_str(ch))
+//   let msg: String = channel_recv(ch)
+
+// ── Core channel API ─────────────────────────────────────────────────────────
+
+// channel_new — create a channel with the given buffer capacity.
+//
+//   capacity: 0 = unbounded (never blocks sender)
+//             N = bounded buffer of N messages (sender blocks when full)
+//
+// Returns a channel handle (Int) to pass to send/recv/close.
+fn channel_new(capacity: Int) -> Int {
+    return __channel_new(capacity)
+}
+
+// channel_send — send a message into the channel.
+//
+// Blocks if the channel is bounded and full.
+// No-op if the channel is already closed.
+fn channel_send(ch: Int, msg: String) {
+    __channel_send(ch, msg)
+}
+
+// channel_recv — receive the next message from the channel.
+//
+// Blocks until a message is available.
+// Returns "" when the channel is closed and all buffered messages are drained.
+// The "" sentinel signals end-of-stream to consumers in a loop.
+fn channel_recv(ch: Int) -> String {
+    return __channel_recv(ch)
+}
+
+// channel_try_recv — non-blocking receive.
+//
+// Returns the next message if one is available, or "" if the channel is empty.
+// Does not block. Callers must distinguish "" (empty) from a legitimate ""
+// message by convention — use a non-empty sentinel in the message protocol.
+fn channel_try_recv(ch: Int) -> String {
+    return __channel_try_recv(ch)
+}
+
+// channel_close — signal that no more messages will be sent.
+//
+// After close, channel_recv continues to drain buffered messages then
+// returns "" on every subsequent call. channel_send on a closed channel
+// is a no-op (the message is dropped).
+fn channel_close(ch: Int) {
+    __channel_close(ch)
+}
+
+// ── channel_pipeline ─────────────────────────────────────────────────────────
+
+// channel_pipeline — producer/consumer pipeline with parallel workers.
+//
+// Reads messages from in_ch, applies fn_name to each, writes results to out_ch.
+// Spawns `workers` concurrent worker threads — each drains in_ch independently,
+// so messages are processed in arrival order within each worker but not globally.
+//
+// fn_name must be an El fn with signature (String) -> String.
+//
+// Call channel_close(in_ch) to signal EOF. Workers exit when they receive "".
+// The caller must also close out_ch after all workers finish (via join).
+//
+//   let in_ch: Int = channel_new(0)
+//   let out_ch: Int = channel_new(0)
+//   channel_pipeline(in_ch, out_ch, "process_item", 4)
+//   channel_send(in_ch, "work-1")
+//   channel_close(in_ch)
+//   let result: String = channel_recv(out_ch)
+fn channel_pipeline(in_ch: Int, out_ch: Int, fn_name: String, workers: Int) {
+    let i: Int = 0
+    while i < workers {
+        let arg: String = "{\"in_ch\":" + int_to_str(in_ch) +
+                          ",\"out_ch\":" + int_to_str(out_ch) +
+                          ",\"fn\":\"" + fn_name + "\"}"
+        let _tid: Int = spawn("_channel_worker", arg)
+        let i = i + 1
+    }
+}
+
+// _channel_worker — internal worker for channel_pipeline.
+//
+// Reads messages from in_ch until it receives "" (closed+empty), applies
+// fn_name to each, and writes results to out_ch. Runs in its own thread
+// (spawned by channel_pipeline).
+fn _channel_worker(arg: String) -> String {
+    let in_ch: Int = str_to_int(json_get(arg, "in_ch"))
+    let out_ch: Int = str_to_int(json_get(arg, "out_ch"))
+    let fn_name: String = json_get(arg, "fn")
+    let running: Bool = true
+    while running {
+        let msg: String = channel_recv(in_ch)
+        if str_eq(msg, "") {
+            let running = false
+        } else {
+            // Spawn fn_name in a child thread so it cannot block the worker loop.
+            let tid: Int = spawn(fn_name, msg)
+            let result: String = join(tid)
+            channel_send(out_ch, result)
+        }
+    }
+    return ""
+}
+
+// ── channel_drain ────────────────────────────────────────────────────────────
+
+// channel_drain — collect all messages from ch into a list.
+//
+// Reads until the channel is closed and empty (recv returns "").
+// Returns a [String] of all messages received.
+//
+// Typical usage: close the channel from the producer side, then call
+// channel_drain from the consumer to collect results.
+fn channel_drain(ch: Int) -> [String] {
+    let results: [String] = el_list_empty()
+    let running: Bool = true
+    while running {
+        let msg: String = channel_recv(ch)
+        if str_eq(msg, "") {
+            let running = false
+        } else {
+            let results = el_list_append(results, msg)
+        }
+    }
+    return results
+}
+
+// ── channel_fan_out ───────────────────────────────────────────────────────────
+
+// channel_fan_out — send every item in a list into a channel.
+//
+//   items: [String] — items to send
+//   ch:    Int      — destination channel
+//
+// Sends all items then closes the channel to signal end-of-stream.
+// Intended for the producer side of a pipeline:
+//
+//   channel_fan_out(items, in_ch)
+//   let results: [String] = channel_drain(out_ch)
+fn channel_fan_out(items: [String], ch: Int) {
+    let n: Int = el_list_len(items)
+    let i: Int = 0
+    while i < n {
+        let item: String = el_list_get(items, i)
+        channel_send(ch, item)
+        let i = i + 1
+    }
+    channel_close(ch)
+}

runtime/engram.el

@@ -0,0 +1,86 @@
+// runtime/engram.el — El wrapper for the engram graph store
+//
+// Thin wrappers over the __engram_* seed primitives defined in el_seed.c.
+// Each function delegates directly to the corresponding seed — no logic here.
+// The seed layer owns all storage, indexing, and graph traversal.
+//
+// Dependencies: runtime/string.el, runtime/json.el
+
+// --- Node creation ---
+
+fn engram_node(content: String, node_type: String, salience: Float) -> String {
+    return __engram_node(content, node_type, salience)
+}
+
+fn engram_node_full(content: String, nt: String, sal: Float, imp: Float,
+                    source: String, lang: String, ts: Int, tags: String) -> String {
+    return __engram_node_full(content, nt, sal, imp, source, lang, ts, tags)
+}
+
+// --- Node retrieval ---
+
+fn engram_get_node(id: String) -> String {
+    return __engram_get_node(id)
+}
+
+fn engram_node_count() -> Int {
+    return __engram_node_count()
+}
+
+// --- Node lifecycle ---
+
+fn engram_strengthen(id: String) -> Bool {
+    return __engram_strengthen(id)
+}
+
+fn engram_forget(id: String) -> Bool {
+    return __engram_forget(id)
+}
+
+// --- Search and scan ---
+
+fn engram_search(query: String, limit: Int) -> String {
+    return __engram_search(query, limit)
+}
+
+fn engram_scan_nodes(limit: Int, offset: Int) -> String {
+    return __engram_scan_nodes(limit, offset)
+}
+
+fn engram_scan_nodes_json(limit: Int, offset: Int) -> String {
+    return __engram_scan_nodes_json(limit, offset)
+}
+
+// --- Graph edges ---
+
+fn engram_connect(from: String, to: String, rel: String, weight: Float) -> Bool {
+    return __engram_connect(from, to, rel, weight)
+}
+
+fn engram_edge_between(a: String, b: String) -> String {
+    return __engram_edge_between(a, b)
+}
+
+// --- Graph traversal ---
+
+fn engram_neighbors(id: String) -> String {
+    return __engram_neighbors(id)
+}
+
+fn engram_neighbors_filtered(id: String, rel: String, min_w: Float) -> String {
+    return __engram_neighbors_filtered(id, rel, min_w)
+}
+
+fn engram_activate(query: String, depth: Int) -> String {
+    return __engram_activate(query, depth)
+}
+
+fn engram_activate_json(query: String, limit: Int) -> String {
+    return __engram_activate_json(query, limit)
+}
+
+// --- Generation ---
+
+fn generate(form: String) -> String {
+    return __generate(form)
+}

runtime/env.el

@@ -0,0 +1,105 @@
+// runtime/env.el — environment and process
+// Covers: environment variables, command-line args, process exit, in-process
+// state store, UUID generation, and list convenience helpers.
+
+// env — read an environment variable.  Returns "" if the variable is not set.
+fn env(key: String) -> String {
+    return __env_get(key)
+}
+
+// args — command-line arguments as a list of strings.
+// __args_json returns a JSON array (e.g. ["prog","arg1","arg2"]).
+// The list is built by iterating over the array.
+fn args() -> [String] {
+    let json: String = __args_json()
+    let n: Int = json_array_len(json)
+    let result: [String] = el_list_empty()
+    let i: Int = 0
+    while i < n {
+        let item: String = json_array_get_string(json, i)
+        let result = el_list_append(result, item)
+        let i = i + 1
+    }
+    return result
+}
+
+// exit_program — terminate the process with the given exit code.
+fn exit_program(code: Int) {
+    __exit_program(code)
+}
+
+// ── List convenience helpers ───────────────────────────────────────────────
+
+// get — index into a list.  Thin alias for el_list_get used throughout the
+// El stdlib so call sites read like `get(lst, i)` rather than the verbose form.
+fn get(lst: [String], i: Int) -> String {
+    return el_list_get(lst, i)
+}
+
+// len — length of a list.
+fn len(lst: [String]) -> Int {
+    return el_list_len(lst)
+}
+
+// ── In-process key-value state store ──────────────────────────────────────
+
+// state_set — store a string value under key.
+fn state_set(key: String, val: String) {
+    __state_set(key, val)
+}
+
+// state_get — retrieve value for key; returns "" if key not present.
+fn state_get(key: String) -> String {
+    return __state_get(key)
+}
+
+// state_del — remove key from the store.
+fn state_del(key: String) {
+    __state_del(key)
+}
+
+// state_keys — all keys currently in the store as a JSON array string.
+fn state_keys() -> String {
+    return __state_keys()
+}
+
+// ── DHARMA runtime helpers ─────────────────────────────────────────────────
+
+// config — read a configuration value from the environment.
+// Returns "" if the variable is not set. Alias for env().
+fn config(key: String) -> String {
+    return __env_get(key)
+}
+
+// log_info — write an [INFO] log line to stdout.
+fn log_info(msg: String) {
+    __println("[INFO] " + msg)
+}
+
+// log_warn — write a [WARN] log line to stdout.
+fn log_warn(msg: String) {
+    __println("[WARN] " + msg)
+}
+
+// list_len — return the number of elements in a list. Alias for el_list_len.
+fn list_len(lst: [String]) -> Int {
+    return el_list_len(lst)
+}
+
+// list_get — return the element at index i in a list. Alias for el_list_get.
+fn list_get(lst: [String], i: Int) -> String {
+    return el_list_get(lst, i)
+}
+
+// ── UUID generation ────────────────────────────────────────────────────────
+
+// uuid_new — generate a new random UUID v4.
+fn uuid_new() -> String {
+    return __uuid_v4()
+}
+
+// uuid_v4 — alias for uuid_new(); explicit version name for callers that
+// need to be precise about the UUID variant.
+fn uuid_v4() -> String {
+    return __uuid_v4()
+}

runtime/exec.el

@@ -0,0 +1,27 @@
+// runtime/exec.el — subprocess execution
+// All four names resolve to the same seed primitives so callers can use
+// whichever name matches their mental model of the operation.
+
+// exec — run a shell command, capture stdout, return as String.
+// Blocks until the subprocess exits (30-second wall-clock deadline in the
+// seed layer).  Returns "" on any error.
+fn exec(cmd: String) -> String {
+    return __exec(cmd)
+}
+
+// exec_bg — fire-and-forget subprocess.  Returns immediately; no stdout.
+fn exec_bg(cmd: String) {
+    __exec_bg(cmd)
+}
+
+// exec_command — alias for exec(); preferred when callers care about side
+// effects (e.g. invoking a build tool) rather than captured output.
+fn exec_command(cmd: String) -> String {
+    return __exec(cmd)
+}
+
+// exec_capture — alias for exec(); preferred when callers explicitly want
+// to capture and process stdout.
+fn exec_capture(cmd: String) -> String {
+    return __exec(cmd)
+}

runtime/fs.el

@@ -0,0 +1,49 @@
+// runtime/fs.el — filesystem operations
+// Thin El wrappers over seed primitives; no logic beyond what is needed
+// to present a clean API.  The heavy lifting lives in el_runtime.c.
+
+fn fs_read(path: String) -> String {
+    return __fs_read(path)
+}
+
+fn fs_write(path: String, content: String) -> Bool {
+    return __fs_write(path, content)
+}
+
+fn fs_exists(path: String) -> Bool {
+    return __fs_exists(path)
+}
+
+fn fs_mkdir(path: String) -> Bool {
+    return __fs_mkdir(path)
+}
+
+fn fs_write_bytes(path: String, bytes: String, n: Int) -> Bool {
+    return __fs_write_bytes(path, bytes, n)
+}
+
+// fs_list — return list of filenames in a directory.
+// __fs_list_raw returns a newline-separated string (possibly with a trailing
+// newline); callers that need a clean list should filter empty strings.
+fn fs_list(path: String) -> [String] {
+    let raw: String = __fs_list_raw(path)
+    return str_split(raw, "\n")
+}
+
+// fs_list_json — return a JSON array of filenames in a directory.
+// Empty strings produced by a trailing newline are stripped before encoding.
+fn fs_list_json(path: String) -> String {
+    let items: [String] = fs_list(path)
+    let n: Int = el_list_len(items)
+    let clean: [String] = el_list_empty()
+    let i: Int = 0
+    while i < n {
+        let item: String = el_list_get(items, i)
+        let trimmed: String = str_trim(item)
+        if !str_eq(trimmed, "") {
+            let clean = el_list_append(clean, "\"" + trimmed + "\"")
+        }
+        let i = i + 1
+    }
+    return json_build_array(clean)
+}

runtime/http.el

@@ -0,0 +1,250 @@
+// runtime/http.el — El HTTP client and server wrappers
+//
+// Thin El layer over seed primitives. All network I/O is performed by the
+// seed; this file provides the public API that El programs import.
+//
+// Seed primitives consumed:
+//   __http_do(method, url, body, headers_json, timeout_ms) -> String
+//   __http_do_to_file(method, url, body, headers_json, out_path) -> Bool
+//   __http_do_map(method, url, body, headers_map, timeout_ms) -> String
+//   __http_do_map_to_file(method, url, body, headers_map, out_path) -> Bool
+//   __http_serve(port, handler_name)
+//   __http_serve_v2(port, handler_name)
+//   __http_response(status, headers_json, body) -> String
+//   __env_get(key) -> String
+//
+// NOTE FOR SEED AGENT: __http_do_map and __http_do_map_to_file must be added
+// to the seed. They are identical to __http_do / __http_do_to_file except
+// they accept an ElMap directly for headers instead of a pre-serialised JSON
+// string. This avoids needing map iteration in El (which has no for-loop or
+// map iterator primitive). The seed implementation maps to headers_from_map()
+// in el_runtime.c.
+//
+// Other builtins used:
+//   str_eq(a, b) -> Bool
+//   str_to_int(s) -> Int
+
+// ── Timeout helper ────────────────────────────────────────────────────────────
+
+// el_http_timeout_ms returns the configured HTTP timeout in milliseconds.
+// Reads EL_HTTP_TIMEOUT_MS from the environment; defaults to 60000 (60s).
+// Returns 60000 if the env var is absent, empty, or non-positive.
+fn el_http_timeout_ms() -> Int {
+    let v: String = __env_get("EL_HTTP_TIMEOUT_MS")
+    if str_eq(v, "") { return 60000 }
+    let n: Int = str_to_int(v)
+    if n <= 0 { return 60000 }
+    return n
+}
+
+// ── HTTP client — simple variants ────────────────────────────────────────────
+
+// http_get performs an HTTP GET request and returns the response body.
+// On transport failure the seed returns an error JSON fragment.
+fn http_get(url: String) -> String {
+    return __http_do("GET", url, "", "{}", el_http_timeout_ms())
+}
+
+// http_post performs an HTTP POST request with the given body.
+// No Content-Type header is set; use http_post_json for JSON payloads.
+fn http_post(url: String, body: String) -> String {
+    return __http_do("POST", url, body, "{}", el_http_timeout_ms())
+}
+
+// http_post_json performs an HTTP POST request with Content-Type:
+// application/json. body must be a valid JSON string.
+fn http_post_json(url: String, body: String) -> String {
+    return __http_do("POST", url, body, "{\"Content-Type\":\"application/json\"}", el_http_timeout_ms())
+}
+
+// http_delete performs an HTTP DELETE request and returns the response body.
+fn http_delete(url: String) -> String {
+    return __http_do("DELETE", url, "", "{}", el_http_timeout_ms())
+}
+
+// ── HTTP client — header map variants ────────────────────────────────────────
+//
+// These accept a Map<String, String> of request headers. The seed's
+// __http_do_map converts the ElMap to a curl_slist internally, matching
+// the headers_from_map() logic in el_runtime.c.
+
+// http_get_with_headers performs an HTTP GET with caller-supplied headers.
+fn http_get_with_headers(url: String, headers: Map<String, String>) -> String {
+    return __http_do_map("GET", url, "", headers, el_http_timeout_ms())
+}
+
+// http_post_with_headers performs an HTTP POST with caller-supplied headers.
+fn http_post_with_headers(url: String, body: String, headers: Map<String, String>) -> String {
+    return __http_do_map("POST", url, body, headers, el_http_timeout_ms())
+}
+
+// http_post_form_auth performs an HTTP POST with
+// Content-Type: application/x-www-form-urlencoded and an Authorization
+// header built from auth_header (the caller passes the full header value,
+// e.g. "Bearer <token>" or "Basic <base64>").
+//
+// Mirrors http_post_form_auth in el_runtime.c: two headers are injected,
+// Content-Type is always set; Authorization is omitted when auth_header is "".
+fn http_post_form_auth(url: String, form_body: String, auth_header: String) -> String {
+    if str_eq(auth_header, "") {
+        return __http_do("POST", url, form_body, "{\"Content-Type\":\"application/x-www-form-urlencoded\"}", el_http_timeout_ms())
+    }
+    return __http_do("POST", url, form_body, "{\"Content-Type\":\"application/x-www-form-urlencoded\",\"Authorization\":\"" + auth_header + "\"}", el_http_timeout_ms())
+}
+
+// ── HTTP client — streaming to file ──────────────────────────────────────────
+//
+// These route the response body directly to a file via the seed, bypassing
+// the El string layer. This preserves embedded NUL bytes in binary payloads
+// (audio, images, etc.) — an El string would truncate at the first NUL.
+// Returns true on success, false on any transport or I/O error.
+
+// http_post_to_file performs an HTTP POST and streams the response body to
+// output_path. Useful for large or binary response payloads.
+fn http_post_to_file(url: String, body: String, headers: Map<String, String>, output_path: String) -> Bool {
+    return __http_do_map_to_file("POST", url, body, headers, output_path)
+}
+
+// http_get_to_file performs an HTTP GET and streams the response body to
+// output_path. Useful for large or binary response payloads.
+fn http_get_to_file(url: String, headers: Map<String, String>, output_path: String) -> Bool {
+    return __http_do_map_to_file("GET", url, "", headers, output_path)
+}
+
+// ── HTTP server ───────────────────────────────────────────────────────────────
+//
+// El programs call http_set_handler(name) to register which El function
+// handles requests, then http_serve(port, name) to start listening.
+// The seed resolves handler names via dlsym — every El fn compiles to a
+// global C symbol with the same name, so self-registration works without
+// any El-level registry.
+//
+// v2 widens the handler signature from
+//   (method, path, body) -> String
+// to
+//   (method, path, headers_map, body) -> String
+// so handlers can inspect incoming headers. Use http_serve_v2 +
+// http_set_handler_v2 for v2 handlers.
+
+// http_set_handler registers name as the active v1 request handler.
+// The seed resolves the symbol via dlsym at call time; no El-level
+// registration is needed. This is a no-op at the El layer.
+fn http_set_handler(name: String) {
+    // no-op: the seed handles handler registration via dlsym
+}
+
+// http_serve starts an HTTP/1.1 server on port, dispatching every request
+// to handler (a v1 handler: fn(method, path, body) -> String).
+// Blocks forever. Accepts both IPv4 and IPv6 (dual-stack).
+fn http_serve(port: Int, handler: String) {
+    __http_serve(port, handler)
+}
+
+// http_set_handler_v2 registers name as the active v2 request handler.
+// No-op at the El layer; the seed uses dlsym.
+fn http_set_handler_v2(name: String) {
+    // no-op: the seed handles handler registration via dlsym
+}
+
+// http_serve_v2 starts an HTTP/1.1 server on port, dispatching every
+// request to handler (a v2 handler: fn(method, path, headers, body) ->
+// String). Blocks forever. Accepts both IPv4 and IPv6 (dual-stack).
+fn http_serve_v2(port: Int, handler: String) {
+    __http_serve_v2(port, handler)
+}
+
+// ── Response construction ─────────────────────────────────────────────────────
+
+// http_response builds a structured response envelope that the HTTP server
+// runtime unpacks into a real HTTP response with the given status code and
+// headers. status must be 100–599 (defaults to 200 outside that range).
+// headers_json must be a JSON object literal (e.g. "{}" or
+// "{\"Content-Type\":\"text/html\"}"); body is the response body string.
+//
+// The envelope format is:
+//   {"el_http_response":1,"status":<n>,"headers":<obj>,"body":"<escaped>"}
+// The runtime detects this prefix and unpacks it; plain string returns from
+// handlers are still supported and are sent as HTTP 200 with auto-detected
+// Content-Type.
+fn http_response(status: Int, headers_json: String, body: String) -> String {
+    return __http_response(status, headers_json, body)
+}
+
+// ── HTTP client — PATCH ───────────────────────────────────────────────────────
+
+// http_patch performs an HTTP PATCH request with Content-Type: application/json.
+fn http_patch(url: String, body: String) -> String {
+    return __http_do("PATCH", url, body, "{\"Content-Type\":\"application/json\"}", el_http_timeout_ms())
+}
+
+// ── HTTP client — Engram variants (optional API key) ──────────────────────────
+//
+// These are used by dharma's db.el to talk to Engram nodes.
+// The key parameter is the X-API-Key header value; pass "" for no auth.
+
+// http_post_engram performs an HTTP POST with Content-Type: application/json
+// and an optional X-API-Key header. If key is "" no auth header is added.
+fn http_post_engram(url: String, key: String, body: String) -> String {
+    if str_eq(key, "") {
+        return __http_do("POST", url, body, "{\"Content-Type\":\"application/json\"}", el_http_timeout_ms())
+    }
+    return __http_do("POST", url, body, "{\"Content-Type\":\"application/json\",\"X-API-Key\":\"" + key + "\"}", el_http_timeout_ms())
+}
+
+// http_get_engram performs an HTTP GET with an optional X-API-Key header.
+fn http_get_engram(url: String, key: String) -> String {
+    if str_eq(key, "") {
+        return __http_do("GET", url, "", "{}", el_http_timeout_ms())
+    }
+    return __http_do("GET", url, "", "{\"X-API-Key\":\"" + key + "\"}", el_http_timeout_ms())
+}
+
+// ── SSE — Server-Sent Events streaming ───────────────────────────────────────
+//
+// Usage pattern for an SSE handler:
+//
+//   fn my_handler(method: String, path: String, headers: Map<String, String>, body: String) -> String {
+//       let fd: Int = http_conn_fd()
+//       http_sse_open(fd)
+//       http_sse_send(fd, "hello")
+//       http_sse_send(fd, "world")
+//       http_sse_close(fd)
+//       return http_sse_sentinel()
+//   }
+//
+// The sentinel return value tells http_serve_v2 NOT to close the connection
+// automatically — the handler already closed it via http_sse_close.
+
+// http_conn_fd returns the raw file descriptor for the current HTTP connection.
+// Only valid inside an http_serve_v2 handler, before the handler returns.
+// Use with http_sse_open / http_sse_send / http_sse_close for streaming.
+fn http_conn_fd() -> Int {
+    return __http_conn_fd()
+}
+
+// http_sse_open sends SSE response headers on the current connection,
+// keeping it open for streaming. Call once at the start of an SSE handler.
+// Returns true on success.
+fn http_sse_open(fd: Int) -> Bool {
+    return __http_sse_open(fd)
+}
+
+// http_sse_send writes one SSE event to the connection.
+// data should not contain newlines (they are added automatically).
+// Returns true if the write succeeded (client still connected).
+fn http_sse_send(fd: Int, data: String) -> Bool {
+    return __http_sse_send(fd, data)
+}
+
+// http_sse_close closes the SSE connection.
+fn http_sse_close(fd: Int) {
+    __http_sse_close(fd)
+    return
+}
+
+// http_sse_sentinel is the return value an SSE handler must return
+// to tell the HTTP server NOT to close the connection automatically.
+// The handler takes ownership of the fd and closes it via http_sse_close.
+fn http_sse_sentinel() -> String {
+    return "__sse__"
+}

runtime/json.el

@@ -0,0 +1,213 @@
+// runtime/json.el — El JSON operations
+//
+// Thin El wrappers over seed JSON primitives, plus pure-El builders and
+// helpers.  Each function here corresponds to (and replaces) a C function
+// from el-compiler/runtime/legacy/el_runtime.c (lines 2692–3333).
+//
+// Seed primitives consumed by this module:
+//   __json_get(json, key)              -> String   (value as string)
+//   __json_get_raw(json, key)          -> String   (raw JSON token)
+//   __json_parse_map(s)                -> Map<String, Any>
+//   __json_stringify_val(v)            -> String
+//   __json_array_len(arr)              -> Int
+//   __json_array_get(arr, i)           -> String   (element as JSON fragment)
+//   __json_array_get_string(arr, i)    -> String   (element as string value)
+//   __json_set(json, key, value)       -> String   (JSON mutation)
+//   __str_to_int(s)                    -> Int
+//   __str_to_float(s)                  -> Float
+
+// ---------------------------------------------------------------------------
+// Core — thin wrappers that delegate directly to seed
+// ---------------------------------------------------------------------------
+
+// json_get — extract a value from a JSON object as a string.
+// Supports dot-path traversal ("a.b.c") and array indices ("items.0.name").
+fn json_get(json: String, key: String) -> String {
+    return __json_get(json, key)
+}
+
+// json_get_raw — extract a raw JSON token (the un-decoded fragment) for a key.
+// Useful when the caller wants to pass a sub-object to another JSON function.
+fn json_get_raw(json: String, key: String) -> String {
+    return __json_get_raw(json, key)
+}
+
+// json_parse — parse a JSON string into a Map<String, Any>.
+// Arrays become ElList; objects become ElMap; scalars are typed values.
+fn json_parse(s: String) -> Map<String, Any> {
+    return __json_parse_map(s)
+}
+
+// json_stringify — serialize an El value (ElMap, ElList, String, Int) to JSON.
+fn json_stringify(v: Any) -> String {
+    return __json_stringify_val(v)
+}
+
+// json_array_len — return the number of elements in a JSON array string.
+fn json_array_len(arr: String) -> Int {
+    return __json_array_len(arr)
+}
+
+// json_array_get — return the i-th element of a JSON array as a JSON fragment.
+// Nested objects and arrays are returned verbatim.  Out-of-range -> "".
+fn json_array_get(arr: String, i: Int) -> String {
+    return __json_array_get(arr, i)
+}
+
+// json_array_get_string — return the i-th element of a JSON array as a plain
+// string value (quotes and escape sequences removed).  Non-string elements
+// and out-of-range indices yield "".
+fn json_array_get_string(arr: String, i: Int) -> String {
+    return __json_array_get_string(arr, i)
+}
+
+// ---------------------------------------------------------------------------
+// Typed extractors — delegate to seed then convert
+// ---------------------------------------------------------------------------
+
+// json_get_string — extract a string value for a key.
+// Equivalent to json_get but named explicitly for readability.
+fn json_get_string(json: String, key: String) -> String {
+    return __json_get(json, key)
+}
+
+// json_get_int — extract an integer value for a key.
+fn json_get_int(json: String, key: String) -> Int {
+    let s: String = __json_get(json, key)
+    return str_to_int(s)
+}
+
+// json_get_float — extract a floating-point value for a key.
+fn json_get_float(json: String, key: String) -> Float {
+    let s: String = __json_get(json, key)
+    return str_to_float(s)
+}
+
+// json_get_bool — extract a boolean value for a key.
+// Returns true only when the raw JSON token is the literal "true".
+fn json_get_bool(json: String, key: String) -> Bool {
+    let s: String = __json_get(json, key)
+    return str_eq(s, "true")
+}
+
+// ---------------------------------------------------------------------------
+// Mutation
+// ---------------------------------------------------------------------------
+
+// json_set — set or insert a key/value pair in a JSON object string.
+// If the key already exists its value is replaced in-place; otherwise the
+// pair is appended before the closing brace.  The value must already be a
+// valid JSON-encoded string (e.g. a quoted string, number, or sub-object).
+fn json_set(json: String, key: String, value: String) -> String {
+    return __json_set(json, key, value)
+}
+
+// ---------------------------------------------------------------------------
+// Pure-El builders — no seed call required
+// ---------------------------------------------------------------------------
+
+// json_build_object — build a JSON object from alternating key/value strings.
+//
+// keys_and_values must contain an even number of elements laid out as:
+//   [key0, val0, key1, val1, ...]
+//
+// Both keys and values are assumed to be plain strings that will be
+// double-quoted and JSON-escaped by this function.  Pass a pre-encoded
+// number or sub-object as the value if you need non-string JSON types.
+//
+// Example:
+//   json_build_object(["name", "alice", "role", "admin"])
+//   -> {"name":"alice","role":"admin"}
+fn json_build_object(keys_and_values: [String]) -> String {
+    let n: Int = el_list_len(keys_and_values)
+    let result: String = "{"
+    let i: Int = 0
+    while i < n - 1 {
+        let key: String = el_list_get(keys_and_values, i)
+        let val: String = el_list_get(keys_and_values, i + 1)
+        let sep: String = if i == 0 { "" } else { "," }
+        let escaped_key: String = json_escape_string(key)
+        let escaped_val: String = json_escape_string(val)
+        let result = result + sep + "\"" + escaped_key + "\":\"" + escaped_val + "\""
+        let i = i + 2
+    }
+    return result + "}"
+}
+
+// json_build_array — build a JSON array from a list of already-JSON-encoded
+// strings.
+//
+// Each element in items must be a valid JSON fragment (quoted string, number,
+// object, array, or literal).  The function joins them with commas and wraps
+// the result in brackets.
+//
+// Example:
+//   json_build_array(["\"alice\"", "\"bob\""])
+//   -> ["alice","bob"]
+fn json_build_array(items: [String]) -> String {
+    let n: Int = el_list_len(items)
+    let result: String = "["
+    let i: Int = 0
+    while i < n {
+        let item: String = el_list_get(items, i)
+        let sep: String = if i == 0 { "" } else { "," }
+        let result = result + sep + item
+        let i = i + 1
+    }
+    return result + "]"
+}
+
+// json_array_push — append a pre-encoded JSON element to a JSON array string.
+// elem must be a valid JSON fragment (e.g. "\"foo\"" or "42").
+// Returns a new JSON array string with elem appended.
+// Example: json_array_push("[]", "\"alice\"") -> "[\"alice\"]"
+fn json_array_push(arr: String, elem: String) -> String {
+    let n: Int = json_array_len(arr)
+    if n == 0 {
+        return "[" + elem + "]"
+    }
+    // arr ends with ']'; insert before it
+    let inner_end: Int = str_last_index_of(arr, "]")
+    if inner_end < 0 {
+        return "[" + elem + "]"
+    }
+    let prefix: String = str_slice(arr, 0, inner_end)
+    return prefix + "," + elem + "]"
+}
+
+// json_escape_string — escape a raw string so it can be safely embedded as a
+// JSON string value.
+//
+// Characters escaped: backslash, double-quote, newline, carriage return, tab.
+// The returned value does NOT include surrounding double-quotes; wrap it in
+// quotes if you need a complete JSON string literal.
+fn json_escape_string(s: String) -> String {
+    let s1: String = str_replace(s, "\\", "\\\\")
+    let s2: String = str_replace(s1, "\"", "\\\"")
+    let s3: String = str_replace(s2, "\n", "\\n")
+    let s4: String = str_replace(s3, "\r", "\\r")
+    let s5: String = str_replace(s4, "\t", "\\t")
+    return s5
+}
+
+// ---------------------------------------------------------------------------
+// DHARMA byte decoding
+// ---------------------------------------------------------------------------
+
+// bytes_to_str — decode a JSON array of integer byte values back to a string.
+// "[104,105]" -> "hi"
+// Inverse of str_to_bytes (defined in string.el). Defined here because it
+// depends on json_array_len and json_array_get_string which live in this file.
+fn bytes_to_str(arr: String) -> String {
+    let n: Int = json_array_len(arr)
+    if n == 0 { return "" }
+    let out: String = __str_alloc(n)
+    let i: Int = 0
+    while i < n {
+        let elem: String = json_array_get_string(arr, i)
+        let b: Int = __str_to_int(elem)
+        out = __str_set_char(out, i, b)
+        i = i + 1
+    }
+    return out
+}

runtime/manifest.el

@@ -0,0 +1,34 @@
+// runtime/manifest.el — El runtime module manifest
+//
+// Load order for runtime compilation. Each module may depend on modules
+// listed before it. The build system concatenates these in this order,
+// then compiles the combined source.
+//
+// Modules:
+//   1. runtime/string.el      — string operations (no dependencies)
+//   2. runtime/math.el        — numeric/float operations (no dependencies)
+//   3. runtime/state.el       — in-process key-value (no dependencies)
+//   4. runtime/env.el         — environment, process, args, uuid
+//   5. runtime/fs.el          — filesystem operations (depends: string)
+//   6. runtime/exec.el        — subprocess execution (depends: string)
+//   7. runtime/time.el        — time, date, calendar (depends: string, math)
+//   8. runtime/json.el        — JSON operations (depends: string)
+//   9. runtime/http.el        — HTTP client+server (depends: string, json)
+//  10. runtime/engram.el      — graph store (depends: string, json)
+//  11. runtime/thread.el      — threading, parallel_map (depends: all above)
+//  12. runtime/collections.el — list/map higher-level ops (depends: string)
+//
+// Build command (from el/ root):
+//   cat runtime/string.el runtime/math.el runtime/state.el runtime/env.el \
+//       runtime/fs.el runtime/exec.el runtime/time.el runtime/json.el \
+//       runtime/http.el runtime/engram.el runtime/thread.el \
+//       runtime/collections.el \
+//       <user-program.el> > combined.el
+//   ./dist/platform/elc combined.el > output.c
+//   cc -std=c11 -I el-compiler/runtime -lcurl -lpthread \
+//      -o output output.c el-compiler/runtime/el_seed.c
+
+// This file itself is not compiled — it is documentation only.
+fn runtime_version() -> String {
+    return "2.0.0-el-native"
+}

runtime/math.el

@@ -0,0 +1,170 @@
+// runtime/math.el — Float math, integer utilities, and numeric conversions.
+//
+// Implements the math/float surface from el-compiler/runtime/legacy/el_runtime.c
+// (lines 303–305 for el_abs/max/min, lines 4725–4771 for float/format ops)
+// in pure El, using seed primitives.
+//
+// Seed primitives consumed:
+//   __sqrt_f(f: Float)             -> Float
+//   __log_f(f: Float)              -> Float
+//   __ln_f(f: Float)               -> Float
+//   __sin_f(f: Float)              -> Float
+//   __cos_f(f: Float)              -> Float
+//   __pi_f()                       -> Float
+//   __float_to_str(f: Float)       -> String
+//   __str_to_float(s: String)      -> Float
+//   __int_to_str(n: Int)           -> String
+//   __str_to_int(s: String)        -> Int
+
+// ---------------------------------------------------------------------------
+// Integer math — el_abs, el_max, el_min.
+//
+// Matches legacy el_abs, el_max, el_min (lines 303–305).
+// ---------------------------------------------------------------------------
+
+// el_abs — absolute value of an integer.
+fn el_abs(n: Int) -> Int {
+    if n < 0 { return -n }
+    return n
+}
+
+// el_max — larger of two integers.
+fn el_max(a: Int, b: Int) -> Int {
+    if a > b { return a }
+    return b
+}
+
+// el_min — smaller of two integers.
+fn el_min(a: Int, b: Int) -> Int {
+    if a < b { return a }
+    return b
+}
+
+// ---------------------------------------------------------------------------
+// Float math — thin wrappers over seed primitives.
+//
+// Matches legacy math_sqrt, math_log, math_ln, math_sin, math_cos, math_pi
+// (lines 4766–4771).
+// ---------------------------------------------------------------------------
+
+// math_sqrt — square root.
+fn math_sqrt(f: Float) -> Float {
+    return __sqrt_f(f)
+}
+
+// math_log — base-10 logarithm.
+fn math_log(f: Float) -> Float {
+    return __log_f(f)
+}
+
+// math_ln — natural logarithm.
+fn math_ln(f: Float) -> Float {
+    return __ln_f(f)
+}
+
+// math_sin — sine (radians).
+fn math_sin(f: Float) -> Float {
+    return __sin_f(f)
+}
+
+// math_cos — cosine (radians).
+fn math_cos(f: Float) -> Float {
+    return __cos_f(f)
+}
+
+// math_pi — the constant π.
+fn math_pi() -> Float {
+    return __pi_f()
+}
+
+// ---------------------------------------------------------------------------
+// Float conversions — float_to_str, int_to_float, float_to_int, str_to_float.
+//
+// Matches legacy float_to_str, int_to_float, float_to_int, str_to_float
+// (lines 4725–4762).
+// ---------------------------------------------------------------------------
+
+// float_to_str — format a float using %g (shortest exact representation).
+// Matches legacy float_to_str() → snprintf "%g".
+fn float_to_str(f: Float) -> String {
+    return __float_to_str(f)
+}
+
+// int_to_float — convert an integer to a float.
+// Matches legacy int_to_float() → (double)(int64_t)n.
+fn int_to_float(n: Int) -> Float {
+    return __int_to_float(n)
+}
+
+// float_to_int — truncate a float to an integer (toward zero).
+// Matches legacy float_to_int() → (int64_t)el_to_float(f).
+fn float_to_int(f: Float) -> Int {
+    return __float_to_int(f)
+}
+
+// str_to_float — parse a float from a string. Returns 0.0 on failure.
+// Matches legacy str_to_float() → strtod(str, NULL).
+fn str_to_float(s: String) -> Float {
+    return __str_to_float(s)
+}
+
+// ---------------------------------------------------------------------------
+// format_float — format a float to a fixed number of decimal places.
+//
+// decimals is clamped to [0, 30]. Matches legacy format_float() → snprintf "%.*f".
+// ---------------------------------------------------------------------------
+
+fn format_float(f: Float, decimals: Int) -> String {
+    let d: Int = decimals
+    if d < 0  { d = 0 }
+    if d > 30 { d = 30 }
+    // Delegate to seed; the seed exposes __format_float(f, d) -> String.
+    // This matches snprintf(buf, 128, "%.*f", d, v) in the legacy runtime.
+    return __format_float(f, d)
+}
+
+// ---------------------------------------------------------------------------
+// decimal_round — round a float to d decimal places (half-away-from-zero).
+//
+// Matches legacy decimal_round():
+//   mul = pow(10, d)
+//   r = (v >= 0 ? floor(v*mul + 0.5) : -floor(-v*mul + 0.5)) / mul
+//
+// We implement pow(10, d) via a loop (d <= 15, so at most 15 multiplications).
+// ---------------------------------------------------------------------------
+
+// _pow10 — 10^n as a Float for n in [0, 15].
+fn _pow10(n: Int) -> Float {
+    let result: Float = 1.0
+    let i: Int = 0
+    while i < n {
+        result = result * 10.0
+        i = i + 1
+    }
+    return result
+}
+
+// _floor_f — floor of a float: largest integer <= f.
+// Uses __float_to_int (truncation) with correction for negative non-integers.
+fn _floor_f(f: Float) -> Float {
+    let t: Int = __float_to_int(f)
+    let tf: Float = __int_to_float(t)
+    // if f was negative and not already an integer, subtract 1
+    if f < 0.0 {
+        if tf > f {
+            return tf - 1.0
+        }
+    }
+    return tf
+}
+
+fn decimal_round(f: Float, decimals: Int) -> Float {
+    let d: Int = decimals
+    if d < 0  { d = 0 }
+    if d > 15 { d = 15 }
+    let mul: Float = _pow10(d)
+    if f >= 0.0 {
+        return _floor_f(f * mul + 0.5) / mul
+    }
+    return 0.0 - _floor_f((0.0 - f) * mul + 0.5) / mul
+}

runtime/state.el

@@ -0,0 +1,61 @@
+// runtime/state.el — In-process key/value store.
+//
+// Thin El wrappers over the __state_* seed primitives. The backing store is
+// a process-wide hash map maintained by the El runtime (formerly el_runtime.c
+// lines 4632–4721: state_set, state_get, state_del, state_keys).
+//
+// Keys and values are Strings. Values are persistent across request boundaries
+// within the same process instance (they survive individual request lifetimes).
+// Concurrent access is serialized by the runtime; these wrappers are lock-free
+// from El's perspective.
+//
+// Seed primitives consumed:
+//   __state_set(key: String, val: String)
+//   __state_get(key: String) -> String
+//   __state_del(key: String)
+//   __state_keys()            -> String   (JSON array of key strings)
+
+// ---------------------------------------------------------------------------
+// Core — set / get / del / keys
+// ---------------------------------------------------------------------------
+
+// state_set — store val under key. Overwrites any existing value.
+fn state_set(key: String, val: String) {
+    __state_set(key, val)
+}
+
+// state_get — retrieve the value for key. Returns "" if key is absent.
+fn state_get(key: String) -> String {
+    return __state_get(key)
+}
+
+// state_del — remove key from the store. No-op if key does not exist.
+fn state_del(key: String) {
+    __state_del(key)
+}
+
+// state_keys — return a JSON array string of all current keys.
+// e.g. ["foo","bar","baz"]
+// Matches legacy state_keys() which returns an ElList (here serialized as JSON).
+fn state_keys() -> String {
+    return __state_keys()
+}
+
+// ---------------------------------------------------------------------------
+// Convenience helpers
+// ---------------------------------------------------------------------------
+
+// state_has — true if key is present (value is non-empty string).
+// Note: a key set to "" is indistinguishable from absent via state_get alone.
+fn state_has(key: String) -> Bool {
+    let v: String = state_get(key)
+    if str_eq(v, "") { return false }
+    return true
+}
+
+// state_get_or — return val for key, or default_val if key is absent.
+fn state_get_or(key: String, default_val: String) -> String {
+    let v: String = state_get(key)
+    if str_eq(v, "") { return default_val }
+    return v
+}

runtime/stdlib.el

@@ -0,0 +1,42 @@
+// stdlib.el — El standard library master import file.
+//
+// Import this single file to get the full El runtime in the correct
+// dependency order. El programs can do:
+//
+//   import "../foundation/el/runtime/stdlib.el"
+//
+// or, if El is installed via tools/install.sh:
+//
+//   import "/usr/local/el/runtime/stdlib.el"
+//
+// Note: test.el is intentionally NOT included here — it is dev-only
+// and should be imported explicitly in test files only.
+//
+// Dependency order (each module may depend on earlier ones):
+//   string   — no deps
+//   math     — no deps
+//   time     — no deps
+//   env      — no deps
+//   fs       — no deps
+//   exec     — no deps
+//   json     — depends on string
+//   http     — depends on string, json
+//   state    — no deps
+//   thread   — depends on exec
+//   channel  — depends on thread, state
+//   engram   — depends on http, json, string
+//   manifest — depends on fs, json, string
+
+import "string.el"
+import "math.el"
+import "time.el"
+import "env.el"
+import "fs.el"
+import "exec.el"
+import "json.el"
+import "http.el"
+import "state.el"
+import "thread.el"
+import "channel.el"
+import "engram.el"
+import "manifest.el"

runtime/string.el

@@ -0,0 +1,907 @@
+// runtime/string.el — String operations implemented in El.
+//
+// All functions delegate character-level work to the seed primitives declared
+// in el_seed.c.  No C is written here; this is pure El source that compiles
+// to C via the normal El pipeline.
+//
+// Seed primitives used (provided by el_seed.c):
+//   __str_len(s)               -> Int
+//   __str_char_at(s, i)        -> Int   (char code at byte index i)
+//   __str_alloc(n)             -> String (n-byte zero-filled mutable buffer)
+//   __str_set_char(s, i, c)    -> String (mutate s[i]=c, return s)
+//   __str_cmp(a, b)            -> Int   (strcmp)
+//   __str_ncmp(a, b, n)        -> Int   (strncmp)
+//   __str_concat_raw(a, b)     -> String
+//   __str_slice_raw(s, lo, hi) -> String (substring copy [lo, hi))
+//   __int_to_str(n)            -> String
+//   __str_to_int(s)            -> Int
+//   __float_to_str(f)          -> String
+//   __str_to_float(s)          -> Float
+//   __println(s)
+//   __print(s)
+//   __readline()               -> String
+//   __url_encode(s)            -> String
+//   __url_decode(s)            -> String
+
+// ── I/O ──────────────────────────────────────────────────────────────────────
+
+fn println(s: String) -> Void {
+    __println(s)
+}
+
+fn print(s: String) -> Void {
+    __print(s)
+}
+
+fn readline() -> String {
+    return __readline()
+}
+
+// ── Type conversions ──────────────────────────────────────────────────────────
+
+fn int_to_str(n: Int) -> String {
+    return __int_to_str(n)
+}
+
+fn str_to_int(s: String) -> Int {
+    return __str_to_int(s)
+}
+
+fn float_to_str(f: Float) -> String {
+    return __float_to_str(f)
+}
+
+fn str_to_float(s: String) -> Float {
+    return __str_to_float(s)
+}
+
+fn bool_to_str(b: Bool) -> String {
+    if b { return "true" }
+    return "false"
+}
+
+// ── URL encoding ──────────────────────────────────────────────────────────────
+
+fn url_encode(s: String) -> String {
+    return __url_encode(s)
+}
+
+fn url_decode(s: String) -> String {
+    return __url_decode(s)
+}
+
+// ── Math ──────────────────────────────────────────────────────────────────────
+
+fn el_abs(n: Int) -> Int {
+    if n < 0 { return 0 - n }
+    return n
+}
+
+fn el_max(a: Int, b: Int) -> Int {
+    if a > b { return a }
+    return b
+}
+
+fn el_min(a: Int, b: Int) -> Int {
+    if a < b { return a }
+    return b
+}
+
+// ── Core string primitives ────────────────────────────────────────────────────
+
+fn str_len(s: String) -> Int {
+    return __str_len(s)
+}
+
+fn str_eq(a: String, b: String) -> Bool {
+    return __str_cmp(a, b) == 0
+}
+
+fn str_concat(a: String, b: String) -> String {
+    return __str_concat_raw(a, b)
+}
+
+fn str_slice(s: String, start: Int, end: Int) -> String {
+    let slen: Int = __str_len(s)
+    let lo: Int = start
+    if lo < 0 { lo = 0 }
+    if lo > slen { lo = slen }
+    let hi: Int = end
+    if hi < lo { hi = lo }
+    if hi > slen { hi = slen }
+    return __str_slice_raw(s, lo, hi)
+}
+
+// ── Whitespace helpers (internal) ─────────────────────────────────────────────
+//
+// _is_ws: returns true for ASCII whitespace (space, tab, \n, \r, \f, \v).
+
+fn _is_ws(c: Int) -> Bool {
+    if c == 32 { return true }   // space
+    if c == 9  { return true }   // tab
+    if c == 10 { return true }   // \n
+    if c == 13 { return true }   // \r
+    if c == 12 { return true }   // \f
+    if c == 11 { return true }   // \v
+    return false
+}
+
+// Scan forward from index 0; return index of first byte not in whitespace,
+// or n if the entire string is whitespace.
+fn _find_first_non_ws(s: String, n: Int) -> Int {
+    let i: Int = 0
+    while i < n {
+        if !_is_ws(__str_char_at(s, i)) { return i }
+        i = i + 1
+    }
+    return n
+}
+
+// Scan backward from index n-1; return index of last non-whitespace byte,
+// or -1 if the entire string is whitespace.
+fn _find_last_non_ws(s: String, n: Int) -> Int {
+    let i: Int = n - 1
+    while i >= 0 {
+        if !_is_ws(__str_char_at(s, i)) { return i }
+        i = i - 1
+    }
+    return -1
+}
+
+// ── Comparison and search ─────────────────────────────────────────────────────
+
+fn str_starts_with(s: String, prefix: String) -> Bool {
+    let plen: Int = __str_len(prefix)
+    let slen: Int = __str_len(s)
+    if plen > slen { return false }
+    return __str_ncmp(s, prefix, plen) == 0
+}
+
+fn str_ends_with(s: String, suffix: String) -> Bool {
+    let slen: Int = __str_len(s)
+    let suflen: Int = __str_len(suffix)
+    if suflen > slen { return false }
+    let tail: String = __str_slice_raw(s, slen - suflen, slen)
+    return __str_cmp(tail, suffix) == 0
+}
+
+fn str_contains(s: String, sub: String) -> Bool {
+    let slen: Int = __str_len(s)
+    let sublen: Int = __str_len(sub)
+    if sublen == 0 { return true }
+    if sublen > slen { return false }
+    let limit: Int = slen - sublen
+    let i: Int = 0
+    while i <= limit {
+        let window: String = __str_slice_raw(s, i, i + sublen)
+        if __str_cmp(window, sub) == 0 { return true }
+        i = i + 1
+    }
+    return false
+}
+
+fn str_index_of(s: String, sub: String) -> Int {
+    let slen: Int = __str_len(s)
+    let sublen: Int = __str_len(sub)
+    if sublen == 0 { return 0 }
+    if sublen > slen { return -1 }
+    let limit: Int = slen - sublen
+    let i: Int = 0
+    while i <= limit {
+        let window: String = __str_slice_raw(s, i, i + sublen)
+        if __str_cmp(window, sub) == 0 { return i }
+        i = i + 1
+    }
+    return -1
+}
+
+fn str_last_index_of(s: String, sub: String) -> Int {
+    let slen: Int = __str_len(s)
+    let sublen: Int = __str_len(sub)
+    if sublen == 0 { return slen }
+    if sublen > slen { return -1 }
+    let last: Int = -1
+    let limit: Int = slen - sublen
+    let i: Int = 0
+    while i <= limit {
+        let window: String = __str_slice_raw(s, i, i + sublen)
+        if __str_cmp(window, sub) == 0 {
+            last = i
+            i = i + sublen
+        } else {
+            i = i + 1
+        }
+    }
+    return last
+}
+
+fn str_index_of_all(s: String, sub: String) -> [Int] {
+    let result: [Int] = el_list_empty()
+    let slen: Int = __str_len(s)
+    let sublen: Int = __str_len(sub)
+    if sublen == 0 { return result }
+    if sublen > slen { return result }
+    let limit: Int = slen - sublen
+    let i: Int = 0
+    while i <= limit {
+        let window: String = __str_slice_raw(s, i, i + sublen)
+        if __str_cmp(window, sub) == 0 {
+            result = el_list_append(result, i)
+            i = i + sublen
+        } else {
+            i = i + 1
+        }
+    }
+    return result
+}
+
+// Return the byte index of the first character in s that appears in any_of,
+// or -1 if none found.
+fn str_find_chars(s: String, any_of: String) -> Int {
+    let slen: Int = __str_len(s)
+    let alen: Int = __str_len(any_of)
+    if alen == 0 { return -1 }
+    let i: Int = 0
+    while i < slen {
+        let c: Int = __str_char_at(s, i)
+        let j: Int = 0
+        while j < alen {
+            if c == __str_char_at(any_of, j) { return i }
+            j = j + 1
+        }
+        i = i + 1
+    }
+    return -1
+}
+
+// ── Character access ──────────────────────────────────────────────────────────
+
+// Return a one-character string at byte index i, or "" if out of range.
+fn str_char_at(s: String, i: Int) -> String {
+    let slen: Int = __str_len(s)
+    if i < 0    { return "" }
+    if i >= slen { return "" }
+    return __str_slice_raw(s, i, i + 1)
+}
+
+// Return the char code (byte value) at byte index i, or 0 if out of range.
+fn str_char_code(s: String, i: Int) -> Int {
+    let slen: Int = __str_len(s)
+    if i < 0    { return 0 }
+    if i >= slen { return 0 }
+    return __str_char_at(s, i)
+}
+
+// ── Case conversion ───────────────────────────────────────────────────────────
+
+fn str_to_upper(s: String) -> String {
+    let n: Int = __str_len(s)
+    if n == 0 { return "" }
+    let out: String = __str_alloc(n)
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        // a-z (97-122) -> A-Z (65-90): subtract 32
+        if c >= 97 {
+            if c <= 122 { c = c - 32 }
+        }
+        out = __str_set_char(out, i, c)
+        i = i + 1
+    }
+    return out
+}
+
+fn str_to_lower(s: String) -> String {
+    let n: Int = __str_len(s)
+    if n == 0 { return "" }
+    let out: String = __str_alloc(n)
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        // A-Z (65-90) -> a-z (97-122): add 32
+        if c >= 65 {
+            if c <= 90 { c = c + 32 }
+        }
+        out = __str_set_char(out, i, c)
+        i = i + 1
+    }
+    return out
+}
+
+// Aliases used in existing El codebases.
+fn str_lower(s: String) -> String {
+    return str_to_lower(s)
+}
+
+fn str_upper(s: String) -> String {
+    return str_to_upper(s)
+}
+
+// ── Whitespace trimming ───────────────────────────────────────────────────────
+
+fn str_trim(s: String) -> String {
+    let n: Int = __str_len(s)
+    if n == 0 { return "" }
+    let lo: Int = _find_first_non_ws(s, n)
+    if lo == n { return "" }
+    let hi: Int = _find_last_non_ws(s, n)
+    return __str_slice_raw(s, lo, hi + 1)
+}
+
+fn str_lstrip(s: String) -> String {
+    let n: Int = __str_len(s)
+    if n == 0 { return "" }
+    let lo: Int = _find_first_non_ws(s, n)
+    if lo == n { return "" }
+    return __str_slice_raw(s, lo, n)
+}
+
+fn str_rstrip(s: String) -> String {
+    let n: Int = __str_len(s)
+    if n == 0 { return "" }
+    let hi: Int = _find_last_non_ws(s, n)
+    if hi < 0 { return "" }
+    return __str_slice_raw(s, 0, hi + 1)
+}
+
+// ── Replacement ───────────────────────────────────────────────────────────────
+
+fn str_replace(s: String, from: String, to: String) -> String {
+    let slen: Int = __str_len(s)
+    let flen: Int = __str_len(from)
+    if flen == 0 { return s }
+    if slen == 0 { return s }
+    // Scan s left-to-right; emit `to` on each match, otherwise emit one byte.
+    let result: String = ""
+    let i: Int = 0
+    while i < slen {
+        // Try to match `from` at position i
+        if i + flen <= slen {
+            let window: String = __str_slice_raw(s, i, i + flen)
+            if __str_cmp(window, from) == 0 {
+                result = __str_concat_raw(result, to)
+                i = i + flen
+            } else {
+                let ch: String = __str_slice_raw(s, i, i + 1)
+                result = __str_concat_raw(result, ch)
+                i = i + 1
+            }
+        } else {
+            // Not enough bytes left for a match — emit remainder and stop.
+            let tail: String = __str_slice_raw(s, i, slen)
+            result = __str_concat_raw(result, tail)
+            i = slen
+        }
+    }
+    return result
+}
+
+// ── Repetition and reversal ───────────────────────────────────────────────────
+
+fn str_repeat(s: String, n: Int) -> String {
+    if n <= 0 { return "" }
+    let slen: Int = __str_len(s)
+    if slen == 0 { return "" }
+    let result: String = ""
+    let i: Int = 0
+    while i < n {
+        result = __str_concat_raw(result, s)
+        i = i + 1
+    }
+    return result
+}
+
+// Byte-reverse (correct for ASCII; for multi-byte UTF-8 codepoints this
+// reverses bytes within a codepoint, which is intentional at this tier —
+// Phase 2 will add grapheme-aware reversal).
+fn str_reverse(s: String) -> String {
+    let n: Int = __str_len(s)
+    if n == 0 { return "" }
+    let out: String = __str_alloc(n)
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        out = __str_set_char(out, n - 1 - i, c)
+        i = i + 1
+    }
+    return out
+}
+
+// ── Prefix/suffix stripping ───────────────────────────────────────────────────
+
+fn str_strip_prefix(s: String, prefix: String) -> String {
+    let slen: Int = __str_len(s)
+    let plen: Int = __str_len(prefix)
+    if plen == 0 { return s }
+    if plen > slen { return s }
+    if __str_ncmp(s, prefix, plen) == 0 {
+        return __str_slice_raw(s, plen, slen)
+    }
+    return s
+}
+
+fn str_strip_suffix(s: String, suffix: String) -> String {
+    let slen: Int = __str_len(s)
+    let suflen: Int = __str_len(suffix)
+    if suflen == 0 { return s }
+    if suflen > slen { return s }
+    let tail: String = __str_slice_raw(s, slen - suflen, slen)
+    if __str_cmp(tail, suffix) == 0 {
+        return __str_slice_raw(s, 0, slen - suflen)
+    }
+    return s
+}
+
+// Strip leading and trailing bytes whose char code appears in `chars`.
+fn str_strip_chars(s: String, chars: String) -> String {
+    let slen: Int = __str_len(s)
+    let clen: Int = __str_len(chars)
+    if slen == 0 { return "" }
+    if clen == 0 { return s }
+    let lo: Int = _find_first_not_in_charset(s, chars, slen, clen)
+    if lo == slen { return "" }
+    let hi: Int = _find_last_not_in_charset(s, chars, slen, clen)
+    return __str_slice_raw(s, lo, hi + 1)
+}
+
+// Internal: true if char code `c` is present in the charset string.
+fn _char_in_set(c: Int, chars: String, clen: Int) -> Bool {
+    let j: Int = 0
+    while j < clen {
+        if c == __str_char_at(chars, j) { return true }
+        j = j + 1
+    }
+    return false
+}
+
+fn _find_first_not_in_charset(s: String, chars: String, slen: Int, clen: Int) -> Int {
+    let i: Int = 0
+    while i < slen {
+        if !_char_in_set(__str_char_at(s, i), chars, clen) { return i }
+        i = i + 1
+    }
+    return slen
+}
+
+fn _find_last_not_in_charset(s: String, chars: String, slen: Int, clen: Int) -> Int {
+    let i: Int = slen - 1
+    while i >= 0 {
+        if !_char_in_set(__str_char_at(s, i), chars, clen) { return i }
+        i = i - 1
+    }
+    return -1
+}
+
+// ── Padding ───────────────────────────────────────────────────────────────────
+
+// Pad s on the left to `width` total chars, repeating `pad` cyclically.
+fn str_pad_left(s: String, width: Int, pad: String) -> String {
+    let slen: Int = __str_len(s)
+    if slen >= width { return s }
+    let plen: Int = __str_len(pad)
+    if plen == 0 { return s }
+    let need: Int = width - slen
+    let prefix: String = ""
+    let i: Int = 0
+    while i < need {
+        // Select pad character at position (i mod plen)
+        let pad_idx: Int = i - (i / plen) * plen
+        let pc: String = __str_slice_raw(pad, pad_idx, pad_idx + 1)
+        prefix = __str_concat_raw(prefix, pc)
+        i = i + 1
+    }
+    return __str_concat_raw(prefix, s)
+}
+
+// Pad s on the right to `width` total chars, repeating `pad` cyclically.
+fn str_pad_right(s: String, width: Int, pad: String) -> String {
+    let slen: Int = __str_len(s)
+    if slen >= width { return s }
+    let plen: Int = __str_len(pad)
+    if plen == 0 { return s }
+    let need: Int = width - slen
+    let suffix: String = ""
+    let i: Int = 0
+    while i < need {
+        let pad_idx: Int = i - (i / plen) * plen
+        let pc: String = __str_slice_raw(pad, pad_idx, pad_idx + 1)
+        suffix = __str_concat_raw(suffix, pc)
+        i = i + 1
+    }
+    return __str_concat_raw(s, suffix)
+}
+
+// ── Counting ──────────────────────────────────────────────────────────────────
+
+// Count non-overlapping occurrences of `sub` in `s`. Empty sub returns 0.
+fn str_count(s: String, sub: String) -> Int {
+    let slen: Int = __str_len(s)
+    let sublen: Int = __str_len(sub)
+    if sublen == 0 { return 0 }
+    if sublen > slen { return 0 }
+    let count: Int = 0
+    let limit: Int = slen - sublen
+    let i: Int = 0
+    while i <= limit {
+        let window: String = __str_slice_raw(s, i, i + sublen)
+        if __str_cmp(window, sub) == 0 {
+            count = count + 1
+            i = i + sublen
+        } else {
+            i = i + 1
+        }
+    }
+    return count
+}
+
+// Byte count — alias of str_len.
+fn str_count_bytes(s: String) -> Int {
+    return __str_len(s)
+}
+
+// UTF-8 codepoint count: count bytes that are NOT continuation bytes (10xxxxxx).
+// Continuation bytes have the pattern 10xxxxxx = 0x80..0xBF (128..191).
+fn str_count_chars(s: String) -> Int {
+    let n: Int = __str_len(s)
+    let count: Int = 0
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        // Continuation bytes are in range [128, 191]; skip them.
+        // All other bytes (< 128 ASCII, or >= 192 leading bytes) start a codepoint.
+        if c < 128 {
+            count = count + 1
+        } else {
+            if c >= 192 { count = count + 1 }
+        }
+        i = i + 1
+    }
+    return count
+}
+
+// Count newline-delimited lines. A trailing newline does NOT add an extra empty line.
+fn str_count_lines(s: String) -> Int {
+    let n: Int = __str_len(s)
+    if n == 0 { return 0 }
+    let count: Int = 0
+    let has_content: Bool = false
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        has_content = true
+        if c == 10 {  // \n
+            count = count + 1
+            has_content = false
+        }
+        i = i + 1
+    }
+    if has_content { count = count + 1 }
+    return count
+}
+
+// Count whitespace-delimited words (non-empty tokens).
+fn str_count_words(s: String) -> Int {
+    let n: Int = __str_len(s)
+    let count: Int = 0
+    let in_word: Bool = false
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        if _is_ws(c) {
+            in_word = false
+        } else {
+            if !in_word {
+                in_word = true
+                count = count + 1
+            }
+        }
+        i = i + 1
+    }
+    return count
+}
+
+// Count ASCII letters [A-Za-z].
+fn str_count_letters(s: String) -> Int {
+    let n: Int = __str_len(s)
+    let count: Int = 0
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        if c >= 65 {
+            if c <= 90 { count = count + 1 }    // A-Z
+        }
+        if c >= 97 {
+            if c <= 122 { count = count + 1 }   // a-z
+        }
+        i = i + 1
+    }
+    return count
+}
+
+// Count ASCII decimal digits [0-9].
+fn str_count_digits(s: String) -> Int {
+    let n: Int = __str_len(s)
+    let count: Int = 0
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        if c >= 48 {
+            if c <= 57 { count = count + 1 }   // '0'-'9'
+        }
+        i = i + 1
+    }
+    return count
+}
+
+// ── Character classification ──────────────────────────────────────────────────
+//
+// For all predicates: empty string -> false.
+// Multi-char string: ALL bytes must satisfy the predicate.
+
+fn is_letter(s: String) -> Bool {
+    let n: Int = __str_len(s)
+    if n == 0 { return false }
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        let ok: Bool = false
+        if c >= 65 { if c <= 90  { ok = true } }   // A-Z
+        if c >= 97 { if c <= 122 { ok = true } }   // a-z
+        if !ok { return false }
+        i = i + 1
+    }
+    return true
+}
+
+fn is_digit(s: String) -> Bool {
+    let n: Int = __str_len(s)
+    if n == 0 { return false }
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        if c < 48 { return false }   // '0'
+        if c > 57 { return false }   // '9'
+        i = i + 1
+    }
+    return true
+}
+
+fn is_alphanumeric(s: String) -> Bool {
+    let n: Int = __str_len(s)
+    if n == 0 { return false }
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        let ok: Bool = false
+        if c >= 48 { if c <= 57  { ok = true } }   // 0-9
+        if c >= 65 { if c <= 90  { ok = true } }   // A-Z
+        if c >= 97 { if c <= 122 { ok = true } }   // a-z
+        if !ok { return false }
+        i = i + 1
+    }
+    return true
+}
+
+fn is_whitespace(s: String) -> Bool {
+    let n: Int = __str_len(s)
+    if n == 0 { return false }
+    let i: Int = 0
+    while i < n {
+        if !_is_ws(__str_char_at(s, i)) { return false }
+        i = i + 1
+    }
+    return true
+}
+
+// ASCII punctuation: 33-47, 58-64, 91-96, 123-126.
+fn is_punctuation(s: String) -> Bool {
+    let n: Int = __str_len(s)
+    if n == 0 { return false }
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        let ok: Bool = false
+        if c >= 33  { if c <= 47  { ok = true } }
+        if c >= 58  { if c <= 64  { ok = true } }
+        if c >= 91  { if c <= 96  { ok = true } }
+        if c >= 123 { if c <= 126 { ok = true } }
+        if !ok { return false }
+        i = i + 1
+    }
+    return true
+}
+
+fn is_uppercase(s: String) -> Bool {
+    let n: Int = __str_len(s)
+    if n == 0 { return false }
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        if c < 65 { return false }   // 'A'
+        if c > 90 { return false }   // 'Z'
+        i = i + 1
+    }
+    return true
+}
+
+fn is_lowercase(s: String) -> Bool {
+    let n: Int = __str_len(s)
+    if n == 0 { return false }
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        if c < 97  { return false }   // 'a'
+        if c > 122 { return false }   // 'z'
+        i = i + 1
+    }
+    return true
+}
+
+// ── Splitting ─────────────────────────────────────────────────────────────────
+
+fn str_split(s: String, sep: String) -> [String] {
+    let result: [String] = el_list_empty()
+    let slen: Int = __str_len(s)
+    let seplen: Int = __str_len(sep)
+    // Empty separator: return the whole string as a single element.
+    if seplen == 0 {
+        result = el_list_append(result, s)
+        return result
+    }
+    let part_start: Int = 0
+    let i: Int = 0
+    while i < slen {
+        if i + seplen <= slen {
+            let window: String = __str_slice_raw(s, i, i + seplen)
+            if __str_cmp(window, sep) == 0 {
+                let part: String = __str_slice_raw(s, part_start, i)
+                result = el_list_append(result, part)
+                i = i + seplen
+                part_start = i
+            } else {
+                i = i + 1
+            }
+        } else {
+            i = i + 1
+        }
+    }
+    // Append remaining tail (may be empty string if s ended with sep).
+    let tail: String = __str_slice_raw(s, part_start, slen)
+    result = el_list_append(result, tail)
+    return result
+}
+
+// Split into at most n parts. The nth part (index n-1) contains the remainder
+// verbatim, including any further separators.  n <= 0 returns [].  n == 1
+// returns [s].
+fn str_split_n(s: String, sep: String, n: Int) -> [String] {
+    let result: [String] = el_list_empty()
+    if n <= 0 { return result }
+    if n == 1 {
+        result = el_list_append(result, s)
+        return result
+    }
+    let slen: Int = __str_len(s)
+    let seplen: Int = __str_len(sep)
+    if seplen == 0 {
+        result = el_list_append(result, s)
+        return result
+    }
+    let part_start: Int = 0
+    let parts: Int = 0
+    let i: Int = 0
+    while i < slen {
+        if parts >= n - 1 {
+            // Reached the split limit — stop splitting, emit the rest below.
+            i = slen
+        } else {
+            if i + seplen <= slen {
+                let window: String = __str_slice_raw(s, i, i + seplen)
+                if __str_cmp(window, sep) == 0 {
+                    let part: String = __str_slice_raw(s, part_start, i)
+                    result = el_list_append(result, part)
+                    i = i + seplen
+                    part_start = i
+                    parts = parts + 1
+                } else {
+                    i = i + 1
+                }
+            } else {
+                i = i + 1
+            }
+        }
+    }
+    // Remainder verbatim.
+    let tail: String = __str_slice_raw(s, part_start, slen)
+    result = el_list_append(result, tail)
+    return result
+}
+
+// Split on newlines. \r\n is folded to \n. Trailing empty line after a
+// final \n is dropped — so "a\nb\n" yields ["a", "b"], not ["a", "b", ""].
+fn str_split_lines(s: String) -> [String] {
+    let result: [String] = el_list_empty()
+    let n: Int = __str_len(s)
+    if n == 0 { return result }
+    let line_start: Int = 0
+    let i: Int = 0
+    while i < n {
+        let c: Int = __str_char_at(s, i)
+        if c == 10 {  // \n
+            let lend: Int = i
+            // Fold \r\n: if the byte before \n is \r, exclude it.
+            if lend > line_start {
+                if __str_char_at(s, lend - 1) == 13 { lend = lend - 1 }
+            }
+            let line: String = __str_slice_raw(s, line_start, lend)
+            result = el_list_append(result, line)
+            line_start = i + 1
+        }
+        i = i + 1
+    }
+    // Trailing content with no terminating \n.
+    if line_start < n {
+        let line: String = __str_slice_raw(s, line_start, n)
+        result = el_list_append(result, line)
+    }
+    return result
+}
+
+// Split into a list of one-byte strings (byte-level chars).
+fn str_split_chars(s: String) -> [String] {
+    let result: [String] = el_list_empty()
+    let n: Int = __str_len(s)
+    let i: Int = 0
+    while i < n {
+        let ch: String = __str_slice_raw(s, i, i + 1)
+        result = el_list_append(result, ch)
+        i = i + 1
+    }
+    return result
+}
+
+// ── Joining ───────────────────────────────────────────────────────────────────
+
+// Join a list of strings with a separator between consecutive elements.
+// Empty list yields "".  Non-string elements should not be passed here.
+fn str_join(parts: [String], sep: String) -> String {
+    let n: Int = el_list_len(parts)
+    if n == 0 { return "" }
+    let result: String = el_list_get(parts, 0)
+    let i: Int = 1
+    while i < n {
+        result = __str_concat_raw(result, sep)
+        result = __str_concat_raw(result, el_list_get(parts, i))
+        i = i + 1
+    }
+    return result
+}
+
+// ── DHARMA byte encoding (str_to_bytes) ──────────────────────────────────────
+//
+// str_to_bytes — encode a string as a JSON array of unsigned byte values.
+// "hi" -> "[104,105]"
+// Used by db.el to store content in Engram JSON nodes as a byte array.
+// Note: bytes_to_str (the inverse) is defined in json.el because it depends
+// on json_array_get_string which is defined there.
+fn str_to_bytes(s: String) -> String {
+    let n: Int = __str_len(s)
+    if n == 0 { return "[]" }
+    let result: String = "["
+    let i: Int = 0
+    while i < n {
+        let b: Int = __str_char_at(s, i)
+        if i > 0 { result = __str_concat_raw(result, ",") }
+        result = __str_concat_raw(result, __int_to_str(b))
+        i = i + 1
+    }
+    return __str_concat_raw(result, "]")
+}
+
+// ── Cryptographic hashing ─────────────────────────────────────────────────────
+
+// hash_sha256 — return the SHA-256 hex digest of a string.
+// Delegates to the __sha256_hex seed primitive.
+fn hash_sha256(s: String) -> String {
+    return __sha256_hex(s)
+}

runtime/test.el

@@ -0,0 +1,320 @@
+// runtime/test.el — El test framework: assertions, registration, and runner.
+//
+// Provides a minimal but complete test harness for El programs. No external
+// dependencies. Written entirely in El using existing runtime primitives.
+//
+// ── Quick-start ──────────────────────────────────────────────────────────────
+//
+// 1. Write a test function with the standard test signature:
+//
+//      fn test_str_eq_works(_: String) -> String {
+//          assert_true(str_eq("a", "a"), "same strings are equal")
+//          assert_false(str_eq("a", "b"), "different strings are not equal")
+//          return ""
+//      }
+//
+// 2. Register it and run:
+//
+//      fn main() -> Void {
+//          test_case("str_eq works", "test_str_eq_works")
+//          test_run_all()
+//      }
+//
+// Test functions must have the signature (String) -> String. The argument is
+// a dummy passed by the threading mechanism (see runtime/thread.el) and should
+// be ignored. The return value is likewise ignored — results flow through the
+// state-based assertion primitives.
+//
+// ── State keys ───────────────────────────────────────────────────────────────
+//
+//   _test_cases       JSON array of {"name":"...","fn":"..."}
+//   _test_pass_count  Int as string — total passing assertions
+//   _test_fail_count  Int as string — total failing assertions
+//   _test_failures    JSON array of failure message strings
+//   _test_current     Name of the test case currently executing
+//
+// ── Dependencies ─────────────────────────────────────────────────────────────
+//
+//   runtime/string.el   — str_eq, str_concat, str_contains, int_to_str, ...
+//   runtime/state.el    — state_set, state_get
+//   runtime/json.el     — json_array_len, json_array_get_string, json_get,
+//                         json_escape_string
+//   runtime/thread.el   — spawn, join (for dynamic dispatch via dlsym)
+
+// ── Internal: JSON array helpers ─────────────────────────────────────────────
+//
+// _test_json_append — append a quoted, escaped string element to a JSON array.
+//
+// Given an existing JSON array string (e.g. '["a","b"]') and a plain string
+// value, returns a new array with the value appended (e.g. '["a","b","c"]').
+//
+// The array must be non-empty — always init with "[]" before calling.
+fn _test_json_append(arr: String, val: String) -> String {
+    let escaped: String = json_escape_string(val)
+    let inner: String = str_slice(arr, 1, str_len(arr) - 1)
+    if str_eq(inner, "") {
+        return "[\"" + escaped + "\"]"
+    }
+    return "[" + inner + ",\"" + escaped + "\"]"
+}
+
+// _test_json_obj_append — append a raw JSON object string to a JSON array.
+//
+// Used to build the _test_cases list where each element is already a
+// JSON object (not a plain string).
+fn _test_json_obj_append(arr: String, obj: String) -> String {
+    let inner: String = str_slice(arr, 1, str_len(arr) - 1)
+    if str_eq(inner, "") {
+        return "[" + obj + "]"
+    }
+    return "[" + inner + "," + obj + "]"
+}
+
+// ── Test registration ─────────────────────────────────────────────────────────
+
+// test_case — register a named test case.
+//
+//   name:    Human-readable test case name (shown in output).
+//   fn_name: Name of a top-level El function with signature
+//            (String) -> String. The function should call assertion
+//            primitives from this module. The String arg it receives is ""
+//            and its return value is ignored.
+//
+// Test cases are stored in the _test_cases state key and executed in
+// registration order by test_run_all().
+fn test_case(name: String, fn_name: String) {
+    let arr: String = state_get("_test_cases")
+    if str_eq(arr, "") { arr = "[]" }
+    let escaped_name: String = json_escape_string(name)
+    let escaped_fn: String = json_escape_string(fn_name)
+    let obj: String = "{\"name\":\"" + escaped_name + "\",\"fn\":\"" + escaped_fn + "\"}"
+    let arr = _test_json_obj_append(arr, obj)
+    state_set("_test_cases", arr)
+}
+
+// ── Test state helpers ────────────────────────────────────────────────────────
+
+// _test_init — reset all test counters and failure lists.
+//
+// Called at the start of test_run_all(). Safe to call multiple times.
+fn _test_init() {
+    state_set("_test_pass_count", "0")
+    state_set("_test_fail_count", "0")
+    state_set("_test_failures", "[]")
+    state_set("_test_current", "")
+}
+
+// _test_inc_pass — increment the global pass counter by 1.
+fn _test_inc_pass() {
+    let n: Int = str_to_int(state_get("_test_pass_count"))
+    state_set("_test_pass_count", int_to_str(n + 1))
+}
+
+// _test_inc_fail — increment the global fail counter by 1.
+fn _test_inc_fail() {
+    let n: Int = str_to_int(state_get("_test_fail_count"))
+    state_set("_test_fail_count", int_to_str(n + 1))
+}
+
+// test_pass — record a passing assertion for the current test case.
+//
+// Increments the pass counter. Called internally by assertions.
+fn test_pass(name: String) {
+    _test_inc_pass()
+}
+
+// test_fail — record a failing assertion for the current test case.
+//
+//   name: assertion label or description (usually the msg parameter)
+//   msg:  detailed failure message including expected/got values
+//
+// Increments the fail counter and appends the message to _test_failures.
+// Also prints the failure immediately for visibility.
+fn test_fail(name: String, msg: String) {
+    _test_inc_fail()
+    let failures: String = state_get("_test_failures")
+    if str_eq(failures, "") { failures = "[]" }
+    let entry: String = "  " + msg
+    let failures = _test_json_append(failures, entry)
+    state_set("_test_failures", failures)
+    println("  FAIL: " + msg)
+}
+
+// ── Assertions ────────────────────────────────────────────────────────────────
+
+// assert_true — assert that condition is true.
+//
+//   condition: the boolean value to test
+//   msg:       description shown on failure
+fn assert_true(condition: Bool, msg: String) {
+    if condition {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": expected true, got false")
+}
+
+// assert_false — assert that condition is false.
+//
+//   condition: the boolean value to test
+//   msg:       description shown on failure
+fn assert_false(condition: Bool, msg: String) {
+    if !condition {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": expected false, got true")
+}
+
+// assert_eq — assert that two strings are equal.
+//
+//   a, b: strings to compare
+//   msg:  description shown on failure (quoted values appended automatically)
+fn assert_eq(a: String, b: String, msg: String) {
+    if str_eq(a, b) {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": expected \"" + b + "\", got \"" + a + "\"")
+}
+
+// assert_int_eq — assert that two integers are equal.
+//
+//   a, b: integers to compare
+//   msg:  description shown on failure
+fn assert_int_eq(a: Int, b: Int, msg: String) {
+    if a == b {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": expected " + int_to_str(b) + ", got " + int_to_str(a))
+}
+
+// assert_neq — assert that two strings are NOT equal.
+//
+//   a, b: strings to compare
+//   msg:  description shown on failure
+fn assert_neq(a: String, b: String, msg: String) {
+    if !str_eq(a, b) {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": expected values to differ, but both are \"" + a + "\"")
+}
+
+// assert_contains — assert that string s contains substring sub.
+//
+//   s:   haystack string
+//   sub: needle substring
+//   msg: description shown on failure
+fn assert_contains(s: String, sub: String, msg: String) {
+    if str_contains(s, sub) {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": \"" + s + "\" does not contain \"" + sub + "\"")
+}
+
+// assert_starts_with — assert that string s starts with prefix.
+//
+//   s:      string to inspect
+//   prefix: expected prefix
+//   msg:    description shown on failure
+fn assert_starts_with(s: String, prefix: String, msg: String) {
+    if str_starts_with(s, prefix) {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": \"" + s + "\" does not start with \"" + prefix + "\"")
+}
+
+// assert_ends_with — assert that string s ends with suffix.
+//
+//   s:      string to inspect
+//   suffix: expected suffix
+//   msg:    description shown on failure
+fn assert_ends_with(s: String, suffix: String, msg: String) {
+    if str_ends_with(s, suffix) {
+        test_pass(msg)
+        return
+    }
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg + ": \"" + s + "\" does not end with \"" + suffix + "\"")
+}
+
+// fail — unconditional test failure.
+//
+//   msg: failure message shown in output
+//
+// Use when a code path that must not be reached is reached, or when an
+// expected exception did not occur.
+fn fail(msg: String) {
+    let test_name: String = state_get("_test_current")
+    test_fail(msg, "[" + test_name + "] " + msg)
+}
+
+// ── Runner ────────────────────────────────────────────────────────────────────
+
+// _test_run_one — execute a single registered test case by name.
+//
+//   name:    the human-readable test case name (set as _test_current)
+//   fn_name: the El function to invoke via the thread mechanism
+//
+// Sets _test_current so that assertions inside the test function know which
+// test they belong to. Spawns and immediately joins the test function in a
+// child thread (same dlsym mechanism as parallel_map) so dynamic dispatch
+// works without needing closures.
+fn _test_run_one(name: String, fn_name: String) {
+    state_set("_test_current", name)
+    let before_fail: Int = str_to_int(state_get("_test_fail_count"))
+    let tid: Int = __thread_create(fn_name, "")
+    __thread_join(tid)
+    let after_fail: Int = str_to_int(state_get("_test_fail_count"))
+    if after_fail == before_fail {
+        println("[test] " + name + " ... PASS")
+    } else {
+        println("[test] " + name + " ... FAIL")
+    }
+}
+
+// test_run_all — execute all registered test cases and print a summary.
+//
+// Iterates through every test case registered via test_case(), runs each one,
+// prints per-test PASS/FAIL status, then prints a summary line.
+//
+// Returns the total number of failing assertions. Exit with this value to
+// signal CI failure:
+//
+//   fn main() -> Int {
+//       test_case("str_eq", "test_str_eq")
+//       return test_run_all()
+//   }
+fn test_run_all() -> Int {
+    _test_init()
+
+    let cases: String = state_get("_test_cases")
+    if str_eq(cases, "") { cases = "[]" }
+
+    let n: Int = json_array_len(cases)
+    let i: Int = 0
+    while i < n {
+        let entry: String = json_array_get(cases, i)
+        let name: String = json_get(entry, "name")
+        let fn_name: String = json_get(entry, "fn")
+        _test_run_one(name, fn_name)
+        i = i + 1
+    }
+
+    let pass_count: Int = str_to_int(state_get("_test_pass_count"))
+    let fail_count: Int = str_to_int(state_get("_test_fail_count"))
+    println("[test] Summary: " + int_to_str(pass_count) + " passed, " + int_to_str(fail_count) + " failed")
+
+    return fail_count
+}

runtime/thread.el

@@ -0,0 +1,225 @@
+// thread.el — El native threading model
+//
+// First-class parallelism for El. Eliminates bash fan-out hacks for parallel
+// HTTP dispatch, concurrent processing pipelines, and any other workload that
+// benefits from concurrent execution.
+//
+// Built on four seed primitives exposed by el_seed.c via dlsym+pthread:
+//   __thread_create(fn_name, arg) -> Int   spawn thread, return tid
+//   __thread_join(tid)            -> String join thread, return result
+//   __mutex_new()                 -> Int    allocate a mutex, return handle
+//   __mutex_lock(m)                         lock mutex
+//   __mutex_unlock(m)                       unlock mutex
+//
+// Every El fn compiles to a global C symbol. __thread_create uses dlsym to
+// look up the function by name and run it in a pthread. This means any El fn
+// with signature (String) -> String is directly threadable.
+
+// ── Core primitives ──────────────────────────────────────────────────────────
+
+// spawn — launch an El function in a new thread.
+//
+//   fn_name: the name of an El fn with signature (String) -> String
+//   arg:     the argument to pass to that fn
+//
+// Returns a thread id (tid) that can be passed to join().
+// The El function must be a top-level fn — its C symbol must be globally
+// visible so dlsym can resolve it.
+fn spawn(fn_name: String, arg: String) -> Int {
+    return __thread_create(fn_name, arg)
+}
+
+// join — wait for a thread to finish and return its result.
+//
+//   tid: the thread id returned by spawn()
+//
+// Blocks until the thread completes. Returns the String value the thread
+// function returned.
+fn join(tid: Int) -> String {
+    return __thread_join(tid)
+}
+
+// ── parallel_map ─────────────────────────────────────────────────────────────
+
+// parallel_map — map an El function over a list of strings concurrently.
+//
+//   items:   [String] — the input list
+//   fn_name: String   — name of an El fn with signature (String) -> String
+//
+// Spawns one thread per item. All threads run concurrently. Joins each thread
+// in input order, so the output list preserves the same order as the input.
+//
+// This is the core primitive that replaces bash fan-out for parallel HTTP.
+// Example — dispatch to N rooms at once:
+//   let responses: [String] = parallel_map(room_payloads, "dispatch_to_room")
+fn parallel_map(items: [String], fn_name: String) -> [String] {
+    let n: Int = el_list_len(items)
+
+    // Phase 1: spawn all threads and collect tids in order.
+    let tids: [String] = el_list_empty()
+    let i = 0
+    while i < n {
+        let item: String = el_list_get(items, i)
+        let tid: Int = spawn(fn_name, item)
+        // Store tid as string so we can hold it in [String].
+        // int_to_str is available as a builtin.
+        let tids = el_list_append(tids, int_to_str(tid))
+        let i = i + 1
+    }
+
+    // Phase 2: join all threads in order, collecting results.
+    let results: [String] = el_list_empty()
+    let j = 0
+    while j < n {
+        let tid_str: String = el_list_get(tids, j)
+        let tid: Int = str_to_int(tid_str)
+        let result: String = join(tid)
+        let results = el_list_append(results, result)
+        let j = j + 1
+    }
+
+    return results
+}
+
+// ── parallel_map_json ────────────────────────────────────────────────────────
+
+// parallel_map_json — parallel_map over a JSON array string.
+//
+//   items_json: String — a JSON array of strings, e.g. '["a","b","c"]'
+//   fn_name:    String — name of an El fn with signature (String) -> String
+//
+// Parses the JSON array into an [String], runs parallel_map, then serialises
+// the result list back to a JSON array string. Both input and output are JSON
+// strings — the common El inter-service format.
+//
+// Example:
+//   let out_json: String = parallel_map_json(rooms_json, "dispatch_to_room")
+fn parallel_map_json(items_json: String, fn_name: String) -> String {
+    let n: Int = json_array_len(items_json)
+
+    // Unpack JSON array into [String].
+    let items: [String] = el_list_empty()
+    let i = 0
+    while i < n {
+        let item: String = json_array_get(items_json, i)
+        let items = el_list_append(items, item)
+        let i = i + 1
+    }
+
+    // Run the concurrent map.
+    let results: [String] = parallel_map(items, fn_name)
+
+    // Repack results into a JSON array string.
+    let m: Int = el_list_len(results)
+    let out: String = "["
+    let j = 0
+    while j < m {
+        let val: String = el_list_get(results, j)
+        if j > 0 {
+            let out = out + ","
+        }
+        // Each result is treated as a raw JSON value (object, array, or
+        // quoted string as returned by the worker fn).
+        let out = out + val
+        let j = j + 1
+    }
+    let out = out + "]"
+    return out
+}
+
+// ── parallel_filter ──────────────────────────────────────────────────────────
+
+// parallel_filter — keep items where fn_name returns "true", concurrently.
+//
+//   items:   [String] — the input list
+//   fn_name: String   — name of an El fn with signature (String) -> String
+//                       that returns "true" to keep the item or anything else
+//                       to discard it
+//
+// Runs the predicate fn on all items in parallel. Collects results in order,
+// preserving the relative order of kept items.
+fn parallel_filter(items: [String], fn_name: String) -> [String] {
+    let n: Int = el_list_len(items)
+
+    // Spawn a predicate thread for every item.
+    let tids: [String] = el_list_empty()
+    let i = 0
+    while i < n {
+        let item: String = el_list_get(items, i)
+        let tid: Int = spawn(fn_name, item)
+        let tids = el_list_append(tids, int_to_str(tid))
+        let i = i + 1
+    }
+
+    // Join in order, keep item if the predicate returned "true".
+    let kept: [String] = el_list_empty()
+    let j = 0
+    while j < n {
+        let item: String = el_list_get(items, j)
+        let tid_str: String = el_list_get(tids, j)
+        let tid: Int = str_to_int(tid_str)
+        let verdict: String = join(tid)
+        if str_eq(verdict, "true") {
+            let kept = el_list_append(kept, item)
+        }
+        let j = j + 1
+    }
+
+    return kept
+}
+
+// ── HTTP helpers ─────────────────────────────────────────────────────────────
+
+// fire_http_post — worker fn for parallel_posts.
+//
+// Expects arg to be a JSON object with "url" and "body" keys:
+//   {"url":"https://...","body":"{...}"}
+//
+// Returns the HTTP response body string. Registered as a global El fn so
+// parallel_map can locate it via dlsym.
+fn fire_http_post(arg: String) -> String {
+    let url: String = json_get(arg, "url")
+    let body: String = json_get(arg, "body")
+    return http_post(url, body)
+}
+
+// parallel_posts — fire a list of HTTP POSTs concurrently.
+//
+//   requests: [String] — each element is a JSON object {"url":"...","body":"..."}
+//
+// Returns [String] of response bodies in the same order as the input.
+//
+// Example — fan out to N room endpoints at once:
+//   let reqs: [String] = el_list_empty()
+//   let reqs = el_list_append(reqs, "{\"url\":\"http://room-a/dispatch\",\"body\":\"" + payload + "\"}")
+//   let reqs = el_list_append(reqs, "{\"url\":\"http://room-b/dispatch\",\"body\":\"" + payload + "\"}")
+//   let responses: [String] = parallel_posts(reqs)
+fn parallel_posts(requests: [String]) -> [String] {
+    return parallel_map(requests, "fire_http_post")
+}
+
+// ── Mutex helpers ────────────────────────────────────────────────────────────
+
+// with_mutex — call fn_name(arg) while holding mutex m.
+//
+//   m:       Int    — mutex handle returned by __mutex_new()
+//   fn_name: String — name of an El fn with signature (String) -> String
+//   arg:     String — argument to pass to fn_name
+//
+// Locks the mutex, spawns fn_name(arg) in a child thread, joins to collect
+// the result, then unlocks. The mutex is held across the entire duration of
+// fn_name's execution, serializing concurrent callers.
+//
+// Note: fn_name must NOT itself acquire the same mutex — that would deadlock.
+// This is the standard reentrant-mutex caveat.
+//
+// Usage:
+//   let m: Int = __mutex_new()
+//   let result: String = with_mutex(m, "update_shared_state", payload)
+fn with_mutex(m: Int, fn_name: String, arg: String) -> String {
+    __mutex_lock(m)
+    let tid: Int = spawn(fn_name, arg)
+    let result: String = join(tid)
+    __mutex_unlock(m)
+    return result
+}

runtime/time.el

@@ -0,0 +1,425 @@
+// runtime/time.el — Time operations, sleep, and formatting.
+//
+// Implements the time surface from el-compiler/runtime/legacy/el_runtime.c
+// (lines 3334–3440, 3471–3656) in pure El, using seed primitives.
+//
+// Seed primitives consumed:
+//   __time_now_ns()                     -> Int   (nanoseconds since Unix epoch)
+//   __sleep_ms(n: Int)
+//   __int_to_str(n: Int)               -> String
+//   __str_to_int(s: String)            -> Int
+//   __float_to_str(f: Float)           -> String
+
+// ---------------------------------------------------------------------------
+// Core — now / sleep
+// ---------------------------------------------------------------------------
+
+// time_now — milliseconds since Unix epoch (UTC). Matches legacy time_now().
+fn time_now() -> Int {
+    return __time_now_ns() / 1000000
+}
+
+// time_now_utc — same as time_now; UTC alias kept for compatibility.
+fn time_now_utc() -> Int {
+    return __time_now_ns() / 1000000
+}
+
+// now_ns — nanoseconds since Unix epoch. Matches el_now_instant().
+fn now_ns() -> Int {
+    return __time_now_ns()
+}
+
+// unix_timestamp — whole seconds since Unix epoch. Matches unix_timestamp().
+fn unix_timestamp() -> Int {
+    return __time_now_ns() / 1000000000
+}
+
+// sleep_secs — block for n seconds. Clamps negatives to 0.
+fn sleep_secs(n: Int) {
+    if n < 0 {
+        __sleep_ms(0)
+    } else {
+        __sleep_ms(n * 1000)
+    }
+}
+
+// sleep_ms — block for n milliseconds. Clamps negatives to 0.
+fn sleep_ms(n: Int) {
+    if n < 0 {
+        __sleep_ms(0)
+    } else {
+        __sleep_ms(n)
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Gregorian decomposition helpers — pure integer arithmetic.
+//
+// Algorithm: civil date from days since Unix epoch (1970-01-01).
+// Based on Howard Hinnant's public-domain civil_from_days formula
+// (http://howardhinnant.github.io/date_algorithms.html), which the legacy
+// gmtime_r call performs under the hood.
+//
+// We expose the pieces as private helpers (leading underscore convention).
+// ---------------------------------------------------------------------------
+
+// _is_leap — 1 if year y is a Gregorian leap year, 0 otherwise.
+fn _is_leap(y: Int) -> Int {
+    if y % 400 == 0 { return 1 }
+    if y % 100 == 0 { return 0 }
+    if y % 4 == 0 { return 1 }
+    return 0
+}
+
+// _days_in_month — number of days in month m of year y (m: 1..12).
+fn _days_in_month(y: Int, m: Int) -> Int {
+    if m == 1 { return 31 }
+    if m == 2 {
+        if _is_leap(y) == 1 { return 29 }
+        return 28
+    }
+    if m == 3 { return 31 }
+    if m == 4 { return 30 }
+    if m == 5 { return 31 }
+    if m == 6 { return 30 }
+    if m == 7 { return 31 }
+    if m == 8 { return 31 }
+    if m == 9 { return 30 }
+    if m == 10 { return 31 }
+    if m == 11 { return 30 }
+    return 31
+}
+
+// _pad2 — zero-pad an integer to at least 2 digits.
+fn _pad2(n: Int) -> String {
+    if n < 10 { return "0" + __int_to_str(n) }
+    return __int_to_str(n)
+}
+
+// _pad4 — zero-pad an integer to at least 4 digits.
+fn _pad4(n: Int) -> String {
+    if n < 10   { return "000" + __int_to_str(n) }
+    if n < 100  { return "00" + __int_to_str(n) }
+    if n < 1000 { return "0" + __int_to_str(n) }
+    return __int_to_str(n)
+}
+
+// _pad3 — zero-pad an integer to at least 3 digits (milliseconds).
+fn _pad3(n: Int) -> String {
+    if n < 10  { return "00" + __int_to_str(n) }
+    if n < 100 { return "0" + __int_to_str(n) }
+    return __int_to_str(n)
+}
+
+// _civil_year_month_day — decompose days-since-epoch (z, may be negative)
+// into year/month/day using the civil_from_days algorithm.
+// Returns a JSON object: {"year":Y,"month":M,"day":D}
+fn _civil_ymd(z: Int) -> String {
+    // shift epoch to 0000-03-01 (makes leap-day math clean)
+    let zz: Int = z + 719468
+    // era: 400-year block
+    let era: Int = zz / 146097
+    if zz < 0 {
+        era = (zz - 146096) / 146097
+    }
+    let doe: Int = zz - era * 146097                     // day-of-era [0, 146096]
+    let yoe: Int = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365  // year-of-era [0, 399]
+    let y: Int = yoe + era * 400
+    let doy: Int = doe - (365 * yoe + yoe / 4 - yoe / 100) // day-of-year [0, 365]
+    let mp: Int = (5 * doy + 2) / 153                   // month in [0, 11] from March
+    let d: Int = doy - (153 * mp + 2) / 5 + 1           // day [1, 31]
+    let m: Int = mp + 3
+    if mp >= 10 { m = mp - 9 }
+    if mp >= 10 { y = y + 1 }
+    return "{\"year\":" + __int_to_str(y) + ",\"month\":" + __int_to_str(m) + ",\"day\":" + __int_to_str(d) + "}"
+}
+
+// ---------------------------------------------------------------------------
+// time_to_parts — decompose a millisecond timestamp into UTC components.
+//
+// Returns a JSON string:
+//   {"year":Y,"month":M,"day":D,"hour":H,"minute":M,"second":S,"ms":MS}
+//
+// Matches legacy time_to_parts() which returns an ElMap with the same keys.
+// ---------------------------------------------------------------------------
+
+fn time_to_parts(ts: Int) -> String {
+    let ms_raw: Int = ts % 1000
+    let ms: Int = ms_raw
+    if ms_raw < 0 { ms = ms_raw + 1000 }
+
+    let s_raw: Int = ts / 1000
+    let s: Int = s_raw
+    if ms_raw < 0 { s = s_raw - 1 }
+
+    // seconds within the day and days since epoch
+    let sec_of_day: Int = s % 86400
+    let day_z: Int = s / 86400
+    // handle negative: floor division
+    if sec_of_day < 0 {
+        sec_of_day = sec_of_day + 86400
+        day_z = day_z - 1
+    }
+
+    let hour: Int = sec_of_day / 3600
+    let rem: Int = sec_of_day % 3600
+    let minute: Int = rem / 60
+    let second: Int = rem % 60
+
+    // date components via civil decomposition
+    let ymd: String = _civil_ymd(day_z)
+    let year: Int = __str_to_int(json_get(ymd, "year"))
+    let month: Int = __str_to_int(json_get(ymd, "month"))
+    let day: Int = __str_to_int(json_get(ymd, "day"))
+
+    return "{\"year\":" + __int_to_str(year) +
+           ",\"month\":" + __int_to_str(month) +
+           ",\"day\":" + __int_to_str(day) +
+           ",\"hour\":" + __int_to_str(hour) +
+           ",\"minute\":" + __int_to_str(minute) +
+           ",\"second\":" + __int_to_str(second) +
+           ",\"ms\":" + __int_to_str(ms) + "}"
+}
+
+// ---------------------------------------------------------------------------
+// time_format — format a millisecond timestamp as a string.
+//
+// fmt "ISO" (or empty) → "YYYY-MM-DDTHH:MM:SS.mmmZ"  (ISO 8601 UTC)
+// Other fmt values are passed as a strftime-style hint; the El runtime
+// implements the most common tokens. Unsupported tokens are passed through.
+//
+// Matches legacy time_format().
+// ---------------------------------------------------------------------------
+
+fn time_format(ts: Int, fmt: String) -> String {
+    let parts: String = time_to_parts(ts)
+    let y: Int = __str_to_int(json_get(parts, "year"))
+    let mo: Int = __str_to_int(json_get(parts, "month"))
+    let d: Int = __str_to_int(json_get(parts, "day"))
+    let h: Int = __str_to_int(json_get(parts, "hour"))
+    let mi: Int = __str_to_int(json_get(parts, "minute"))
+    let s: Int = __str_to_int(json_get(parts, "second"))
+    let ms: Int = __str_to_int(json_get(parts, "ms"))
+
+    // ISO 8601 UTC: YYYY-MM-DDTHH:MM:SS.mmmZ
+    if str_eq(fmt, "ISO") {
+        return _pad4(y) + "-" + _pad2(mo) + "-" + _pad2(d) +
+               "T" + _pad2(h) + ":" + _pad2(mi) + ":" + _pad2(s) +
+               "." + _pad3(ms) + "Z"
+    }
+    if str_eq(fmt, "") {
+        return _pad4(y) + "-" + _pad2(mo) + "-" + _pad2(d) +
+               "T" + _pad2(h) + ":" + _pad2(mi) + ":" + _pad2(s) +
+               "." + _pad3(ms) + "Z"
+    }
+
+    // strftime-subset: replace common tokens
+    let out: String = fmt
+    let out = str_replace(out, "%Y", _pad4(y))
+    let out = str_replace(out, "%m", _pad2(mo))
+    let out = str_replace(out, "%d", _pad2(d))
+    let out = str_replace(out, "%H", _pad2(h))
+    let out = str_replace(out, "%M", _pad2(mi))
+    let out = str_replace(out, "%S", _pad2(s))
+    let out = str_replace(out, "%3N", _pad3(ms))
+    return out
+}
+
+// ---------------------------------------------------------------------------
+// time_from_parts — construct a ms timestamp from seconds + nanosecond offset.
+//
+// Matches legacy time_from_parts(secs, ns, tz) — tz is ignored (UTC assumed).
+// ---------------------------------------------------------------------------
+
+fn time_from_parts(secs: Int, ns: Int, tz: String) -> Int {
+    return secs * 1000 + ns / 1000000
+}
+
+// ---------------------------------------------------------------------------
+// time_add — add a duration to a millisecond timestamp.
+//
+// unit: "ms" | "sec" | "min" | "hour" | "day"
+// Matches legacy time_add().
+// ---------------------------------------------------------------------------
+
+fn time_add(ts: Int, n: Int, unit: String) -> Int {
+    if str_eq(unit, "ms")   { return ts + n }
+    if str_eq(unit, "sec")  { return ts + n * 1000 }
+    if str_eq(unit, "min")  { return ts + n * 60000 }
+    if str_eq(unit, "hour") { return ts + n * 3600000 }
+    if str_eq(unit, "day")  { return ts + n * 86400000 }
+    // default: treat as ms
+    return ts + n
+}
+
+// ---------------------------------------------------------------------------
+// time_diff — compute the difference between two millisecond timestamps.
+//
+// Returns ts2 - ts1 in the given unit.
+// unit: "ms" | "sec" | "min" | "hour" | "day"
+// Matches legacy time_diff().
+// ---------------------------------------------------------------------------
+
+fn time_diff(ts1: Int, ts2: Int, unit: String) -> Int {
+    let d: Int = ts2 - ts1
+    if str_eq(unit, "ms")   { return d }
+    if str_eq(unit, "sec")  { return d / 1000 }
+    if str_eq(unit, "min")  { return d / 60000 }
+    if str_eq(unit, "hour") { return d / 3600000 }
+    if str_eq(unit, "day")  { return d / 86400000 }
+    return d
+}
+
+// ---------------------------------------------------------------------------
+// Instant / Duration — nanosecond-precision temporal types.
+//
+// These match the el_now_instant, duration_seconds, duration_millis, etc.
+// family from legacy lines 3471–3656. Both Instant and Duration are Int
+// (nanoseconds); the type distinction is at the call-site convention level.
+// ---------------------------------------------------------------------------
+
+// now — current Instant in nanoseconds. Alias for __time_now_ns().
+fn now() -> Int {
+    return __time_now_ns()
+}
+
+// unix_seconds — Instant from whole seconds since epoch.
+fn unix_seconds(n: Int) -> Int {
+    return n * 1000000000
+}
+
+// unix_millis — Instant from milliseconds since epoch.
+fn unix_millis(n: Int) -> Int {
+    return n * 1000000
+}
+
+// instant_to_unix_seconds — convert Instant nanoseconds to whole seconds.
+fn instant_to_unix_seconds(i: Int) -> Int {
+    return i / 1000000000
+}
+
+// instant_to_unix_millis — convert Instant nanoseconds to milliseconds.
+fn instant_to_unix_millis(i: Int) -> Int {
+    return i / 1000000
+}
+
+// instant_to_iso8601 — format an Instant (nanoseconds) as ISO 8601 UTC.
+fn instant_to_iso8601(i: Int) -> String {
+    let ms: Int = i / 1000000
+    return time_format(ms, "ISO")
+}
+
+// duration_seconds — Duration from n whole seconds.
+fn duration_seconds(n: Int) -> Int {
+    return n * 1000000000
+}
+
+// duration_millis — Duration from n milliseconds.
+fn duration_millis(n: Int) -> Int {
+    return n * 1000000
+}
+
+// duration_nanos — Duration from n nanoseconds (identity).
+fn duration_nanos(n: Int) -> Int {
+    return n
+}
+
+// duration_to_seconds — convert a Duration (nanoseconds) to whole seconds.
+fn duration_to_seconds(d: Int) -> Int {
+    return d / 1000000000
+}
+
+// duration_to_millis — convert a Duration (nanoseconds) to milliseconds.
+fn duration_to_millis(d: Int) -> Int {
+    return d / 1000000
+}
+
+// duration_to_nanos — return the Duration as nanoseconds (identity).
+fn duration_to_nanos(d: Int) -> Int {
+    return d
+}
+
+// sleep_duration — sleep for a Duration (nanoseconds). Clamps negatives to 0.
+fn sleep_duration(dur: Int) {
+    let ms: Int = dur / 1000000
+    if ms < 0 {
+        __sleep_ms(0)
+    } else {
+        __sleep_ms(ms)
+    }
+}
+
+// ---------------------------------------------------------------------------
+// TTL cache — time-bounded key/value backed by state.
+//
+// Matches legacy ttl_cache_set / ttl_cache_get / ttl_cache_age (lines 3663–3717).
+// max_age is a Duration (nanoseconds).
+// ---------------------------------------------------------------------------
+
+// ttl_cache_set — store a value and record the current Instant for TTL checks.
+fn ttl_cache_set(key: String, value: String) {
+    state_set(key, value)
+    let stamp_key: String = "__ttl_at:" + key
+    let now_str: String = __int_to_str(__time_now_ns())
+    state_set(stamp_key, now_str)
+}
+
+// ttl_cache_get — return value if age < max_age (nanoseconds), else "".
+fn ttl_cache_get(key: String, max_age: Int) -> String {
+    let stamp_key: String = "__ttl_at:" + key
+    let sv: String = state_get(stamp_key)
+    if str_eq(sv, "") { return "" }
+    let set_at: Int = __str_to_int(sv)
+    let now_ns: Int = __time_now_ns()
+    let age: Int = now_ns - set_at
+    if age < 0 { return "" }
+    if age > max_age { return "" }
+    return state_get(key)
+}
+
+// ttl_cache_age — nanoseconds since a key was last set (INT_MAX sentinel if missing).
+fn ttl_cache_age(key: String) -> Int {
+    let stamp_key: String = "__ttl_at:" + key
+    let sv: String = state_get(stamp_key)
+    if str_eq(sv, "") { return 9223372036854775807 }
+    let set_at: Int = __str_to_int(sv)
+    return __time_now_ns() - set_at
+}
+
+// ---------------------------------------------------------------------------
+// uuid_new / uuid_v4 — generate a UUID v4 string.
+//
+// Delegates to the __uuid_v4() seed primitive.
+// Matches legacy uuid_new() / uuid_v4() (lines 4602–4621).
+// ---------------------------------------------------------------------------
+
+fn uuid_new() -> String {
+    return __uuid_v4()
+}
+
+fn uuid_v4() -> String {
+    return __uuid_v4()
+}
+
+// ---------------------------------------------------------------------------
+// DHARMA-compatible aliases — millisecond-precision timestamps.
+//
+// now_millis, unix_timestamp_ms, and time_now_ms all return the same value:
+// milliseconds since the Unix epoch. They exist because different parts of
+// the dharma codebase use different names for the same concept.
+// ---------------------------------------------------------------------------
+
+// now_millis — milliseconds since Unix epoch. Alias for time_now().
+fn now_millis() -> Int {
+    return __time_now_ns() / 1000000
+}
+
+// unix_timestamp_ms — same as now_millis.
+fn unix_timestamp_ms() -> Int {
+    return __time_now_ns() / 1000000
+}
+
+// time_now_ms — same as now_millis.
+fn time_now_ms() -> Int {
+    return __time_now_ns() / 1000000
+}

tests/runtime/string_test.el

@@ -0,0 +1,341 @@
+// tests/runtime/string_test.el — Test suite for runtime/string.el
+//
+// Exercises every public function exported by runtime/string.el using the
+// runtime/test.el framework. Each test function covers one string primitive
+// or a tight family of related functions.
+//
+// ── Build and run ────────────────────────────────────────────────────────────
+//
+//   # Combine runtime modules + test framework + this file, then compile:
+//   cat runtime/string.el runtime/math.el runtime/state.el runtime/env.el \
+//       runtime/fs.el runtime/exec.el runtime/time.el runtime/json.el \
+//       runtime/http.el runtime/engram.el runtime/thread.el \
+//       runtime/test.el \
+//       tests/runtime/string_test.el > /tmp/string_test_combined.el
+//
+//   ./dist/platform/elc /tmp/string_test_combined.el > /tmp/string_test.c
+//   cc -std=c11 -I el-compiler/runtime -lcurl -lpthread \
+//      -o /tmp/string_test /tmp/string_test.c el-compiler/runtime/el_seed.c
+//   /tmp/string_test; echo "exit: $?"
+//
+// Exit code equals the number of failing assertions (0 = all pass).
+//
+// ── Coverage ─────────────────────────────────────────────────────────────────
+//
+//   str_eq            str_neq (via assert_neq)
+//   str_len           str_concat
+//   str_starts_with   str_ends_with
+//   str_contains      str_index_of
+//   str_slice         str_replace
+//   str_to_upper      str_to_lower
+//   str_trim          str_lstrip / str_rstrip
+//   str_split         str_join
+//   int_to_str        str_to_int
+//   str_repeat        str_reverse
+//   str_count
+
+// ── str_eq ────────────────────────────────────────────────────────────────────
+
+fn test_str_eq(_: String) -> String {
+    assert_true(str_eq("hello", "hello"), "identical strings are equal")
+    assert_false(str_eq("hello", "world"), "different strings are not equal")
+    assert_true(str_eq("", ""), "empty strings are equal")
+    assert_false(str_eq("a", ""), "non-empty vs empty is not equal")
+    assert_false(str_eq("", "a"), "empty vs non-empty is not equal")
+    assert_false(str_eq("Hello", "hello"), "case-sensitive comparison")
+    return ""
+}
+
+// ── str_len ───────────────────────────────────────────────────────────────────
+
+fn test_str_len(_: String) -> String {
+    assert_int_eq(str_len(""), 0, "empty string has length 0")
+    assert_int_eq(str_len("a"), 1, "single char has length 1")
+    assert_int_eq(str_len("hello"), 5, "hello has length 5")
+    assert_int_eq(str_len("hello world"), 11, "space included in length")
+    return ""
+}
+
+// ── str_concat ────────────────────────────────────────────────────────────────
+
+fn test_str_concat(_: String) -> String {
+    assert_eq(str_concat("hello", " world"), "hello world", "basic concat")
+    assert_eq(str_concat("", "world"), "world", "empty prefix")
+    assert_eq(str_concat("hello", ""), "hello", "empty suffix")
+    assert_eq(str_concat("", ""), "", "both empty")
+    return ""
+}
+
+// ── str_starts_with ───────────────────────────────────────────────────────────
+
+fn test_str_starts_with(_: String) -> String {
+    assert_true(str_starts_with("hello world", "hello"), "prefix present")
+    assert_false(str_starts_with("hello world", "world"), "not a prefix")
+    assert_true(str_starts_with("hello", "hello"), "string is its own prefix")
+    assert_true(str_starts_with("hello", ""), "empty prefix always true")
+    assert_false(str_starts_with("", "a"), "empty string has no prefix")
+    assert_false(str_starts_with("hi", "hello"), "prefix longer than string")
+    return ""
+}
+
+// ── str_ends_with ─────────────────────────────────────────────────────────────
+
+fn test_str_ends_with(_: String) -> String {
+    assert_true(str_ends_with("hello world", "world"), "suffix present")
+    assert_false(str_ends_with("hello world", "hello"), "not a suffix")
+    assert_true(str_ends_with("hello", "hello"), "string is its own suffix")
+    assert_true(str_ends_with("hello", ""), "empty suffix always true")
+    assert_false(str_ends_with("", "a"), "empty string has no suffix")
+    assert_false(str_ends_with("hi", "world"), "suffix longer than string")
+    return ""
+}
+
+// ── str_contains ─────────────────────────────────────────────────────────────
+
+fn test_str_contains(_: String) -> String {
+    assert_true(str_contains("hello world", "world"), "contains at end")
+    assert_true(str_contains("hello world", "hello"), "contains at start")
+    assert_true(str_contains("hello world", "lo wo"), "contains in middle")
+    assert_false(str_contains("hello world", "xyz"), "not contained")
+    assert_true(str_contains("hello", ""), "empty sub always contained")
+    assert_false(str_contains("", "a"), "empty string contains nothing")
+    assert_true(str_contains("hello", "hello"), "string contains itself")
+    return ""
+}
+
+// ── str_index_of ─────────────────────────────────────────────────────────────
+
+fn test_str_index_of(_: String) -> String {
+    assert_int_eq(str_index_of("hello world", "world"), 6, "index of suffix")
+    assert_int_eq(str_index_of("hello world", "hello"), 0, "index of prefix")
+    assert_int_eq(str_index_of("hello world", "o"), 4, "index of first occurrence")
+    assert_int_eq(str_index_of("hello world", "xyz"), -1, "not found returns -1")
+    assert_int_eq(str_index_of("hello", ""), 0, "empty sub returns 0")
+    assert_int_eq(str_index_of("", "a"), -1, "search in empty string")
+    assert_int_eq(str_index_of("aababc", "ab"), 1, "finds first occurrence")
+    return ""
+}
+
+// ── str_replace ───────────────────────────────────────────────────────────────
+
+fn test_str_replace(_: String) -> String {
+    assert_eq(str_replace("hello world", "world", "there"), "hello there", "basic replace")
+    assert_eq(str_replace("aaa", "a", "b"), "bbb", "replace all occurrences")
+    assert_eq(str_replace("hello", "xyz", "abc"), "hello", "no match is identity")
+    assert_eq(str_replace("", "a", "b"), "", "empty string unchanged")
+    assert_eq(str_replace("hello", "", "x"), "hello", "empty from is identity")
+    assert_eq(str_replace("hello hello", "hello", "bye"), "bye bye", "replace multiple")
+    assert_eq(str_replace("aXbXc", "X", "-"), "a-b-c", "single-char delimiter")
+    return ""
+}
+
+// ── str_slice ─────────────────────────────────────────────────────────────────
+
+fn test_str_slice(_: String) -> String {
+    assert_eq(str_slice("hello world", 0, 5), "hello", "slice from start")
+    assert_eq(str_slice("hello world", 6, 11), "world", "slice from middle")
+    assert_eq(str_slice("hello world", 0, 0), "", "zero-length slice")
+    assert_eq(str_slice("hello", 0, 100), "hello", "end beyond length clamped")
+    assert_eq(str_slice("hello", 3, 3), "", "start == end is empty")
+    assert_eq(str_slice("hello world", 2, 7), "llo w", "interior slice")
+    return ""
+}
+
+// ── str_to_upper / str_to_lower ──────────────────────────────────────────────
+
+fn test_str_to_upper(_: String) -> String {
+    assert_eq(str_to_upper("hello"), "HELLO", "lowercase to uppercase")
+    assert_eq(str_to_upper("HELLO"), "HELLO", "already uppercase unchanged")
+    assert_eq(str_to_upper("Hello World"), "HELLO WORLD", "mixed case")
+    assert_eq(str_to_upper(""), "", "empty string unchanged")
+    assert_eq(str_to_upper("hello123"), "HELLO123", "digits unchanged")
+    return ""
+}
+
+fn test_str_to_lower(_: String) -> String {
+    assert_eq(str_to_lower("HELLO"), "hello", "uppercase to lowercase")
+    assert_eq(str_to_lower("hello"), "hello", "already lowercase unchanged")
+    assert_eq(str_to_lower("Hello World"), "hello world", "mixed case")
+    assert_eq(str_to_lower(""), "", "empty string unchanged")
+    assert_eq(str_to_lower("HELLO123"), "hello123", "digits unchanged")
+    return ""
+}
+
+// ── str_trim ─────────────────────────────────────────────────────────────────
+
+fn test_str_trim(_: String) -> String {
+    assert_eq(str_trim("  hello  "), "hello", "trims spaces both sides")
+    assert_eq(str_trim("hello"), "hello", "no whitespace unchanged")
+    assert_eq(str_trim("   "), "", "all-space string becomes empty")
+    assert_eq(str_trim(""), "", "empty string unchanged")
+    assert_eq(str_trim("\t hello \n"), "hello", "trims tabs and newlines")
+    assert_eq(str_trim("  hello world  "), "hello world", "internal spaces preserved")
+    return ""
+}
+
+// ── str_split ─────────────────────────────────────────────────────────────────
+
+fn test_str_split(_: String) -> String {
+    let parts: [String] = str_split("a,b,c", ",")
+    assert_int_eq(el_list_len(parts), 3, "split yields 3 parts")
+    assert_eq(el_list_get(parts, 0), "a", "first part is a")
+    assert_eq(el_list_get(parts, 1), "b", "second part is b")
+    assert_eq(el_list_get(parts, 2), "c", "third part is c")
+
+    let single: [String] = str_split("hello", ",")
+    assert_int_eq(el_list_len(single), 1, "no sep found yields 1 part")
+    assert_eq(el_list_get(single, 0), "hello", "single part is the full string")
+
+    let trailing: [String] = str_split("a,b,", ",")
+    assert_int_eq(el_list_len(trailing), 3, "trailing sep yields empty last element")
+    assert_eq(el_list_get(trailing, 2), "", "last element is empty")
+
+    let empty_str: [String] = str_split("", ",")
+    assert_int_eq(el_list_len(empty_str), 1, "splitting empty string yields one empty element")
+
+    let multi: [String] = str_split("one::two::three", "::")
+    assert_int_eq(el_list_len(multi), 3, "multi-char separator works")
+    assert_eq(el_list_get(multi, 0), "one", "multi-sep first part")
+    assert_eq(el_list_get(multi, 2), "three", "multi-sep last part")
+    return ""
+}
+
+// ── str_join ─────────────────────────────────────────────────────────────────
+
+fn test_str_join(_: String) -> String {
+    let parts: [String] = el_list_empty()
+    let parts = el_list_append(parts, "a")
+    let parts = el_list_append(parts, "b")
+    let parts = el_list_append(parts, "c")
+    assert_eq(str_join(parts, ","), "a,b,c", "basic join with comma")
+    assert_eq(str_join(parts, ""), "abc", "join with empty separator")
+    assert_eq(str_join(parts, " | "), "a | b | c", "join with multi-char sep")
+
+    let empty_list: [String] = el_list_empty()
+    assert_eq(str_join(empty_list, ","), "", "joining empty list yields empty string")
+
+    let one: [String] = el_list_empty()
+    let one = el_list_append(one, "solo")
+    assert_eq(str_join(one, ","), "solo", "joining single element yields that element")
+    return ""
+}
+
+// ── int_to_str / str_to_int ──────────────────────────────────────────────────
+
+fn test_int_to_str(_: String) -> String {
+    assert_eq(int_to_str(0), "0", "zero")
+    assert_eq(int_to_str(42), "42", "positive integer")
+    assert_eq(int_to_str(-1), "-1", "negative integer")
+    assert_eq(int_to_str(1000000), "1000000", "large integer")
+    return ""
+}
+
+fn test_str_to_int(_: String) -> String {
+    assert_int_eq(str_to_int("0"), 0, "zero")
+    assert_int_eq(str_to_int("42"), 42, "positive integer")
+    assert_int_eq(str_to_int("-1"), -1, "negative integer")
+    assert_int_eq(str_to_int("1000000"), 1000000, "large integer")
+    return ""
+}
+
+// ── str_repeat ────────────────────────────────────────────────────────────────
+
+fn test_str_repeat(_: String) -> String {
+    assert_eq(str_repeat("ab", 3), "ababab", "repeat 3 times")
+    assert_eq(str_repeat("x", 1), "x", "repeat once")
+    assert_eq(str_repeat("x", 0), "", "repeat zero times yields empty")
+    assert_eq(str_repeat("", 5), "", "repeating empty string yields empty")
+    assert_eq(str_repeat("-", 4), "----", "single char repeat")
+    return ""
+}
+
+// ── str_reverse ───────────────────────────────────────────────────────────────
+
+fn test_str_reverse(_: String) -> String {
+    assert_eq(str_reverse("hello"), "olleh", "basic reverse")
+    assert_eq(str_reverse("a"), "a", "single char is its own reverse")
+    assert_eq(str_reverse(""), "", "empty string reverses to empty")
+    assert_eq(str_reverse("abcd"), "dcba", "even-length reverse")
+    assert_eq(str_reverse("racecar"), "racecar", "palindrome is unchanged")
+    return ""
+}
+
+// ── str_count ─────────────────────────────────────────────────────────────────
+
+fn test_str_count(_: String) -> String {
+    assert_int_eq(str_count("hello world hello", "hello"), 2, "two occurrences")
+    assert_int_eq(str_count("aaa", "a"), 3, "adjacent single chars")
+    assert_int_eq(str_count("aaa", "aa"), 1, "non-overlapping: one match")
+    assert_int_eq(str_count("hello", "xyz"), 0, "no match")
+    assert_int_eq(str_count("", "a"), 0, "empty string has no occurrences")
+    assert_int_eq(str_count("hello", ""), 0, "empty sub returns 0")
+    return ""
+}
+
+// ── str_strip_prefix / str_strip_suffix ───────────────────────────────────────
+
+fn test_str_strip_prefix(_: String) -> String {
+    assert_eq(str_strip_prefix("foobar", "foo"), "bar", "strips matching prefix")
+    assert_eq(str_strip_prefix("foobar", "baz"), "foobar", "no-match is identity")
+    assert_eq(str_strip_prefix("hello", ""), "hello", "empty prefix is identity")
+    assert_eq(str_strip_prefix("hello", "hello"), "", "full match yields empty")
+    return ""
+}
+
+fn test_str_strip_suffix(_: String) -> String {
+    assert_eq(str_strip_suffix("hello.md", ".md"), "hello", "strips matching suffix")
+    assert_eq(str_strip_suffix("hello.md", ".txt"), "hello.md", "no-match is identity")
+    assert_eq(str_strip_suffix("hello", ""), "hello", "empty suffix is identity")
+    assert_eq(str_strip_suffix("hello", "hello"), "", "full match yields empty")
+    return ""
+}
+
+// ── str_find_chars ────────────────────────────────────────────────────────────
+
+fn test_str_find_chars(_: String) -> String {
+    assert_int_eq(str_find_chars("hello world", " "), 5, "finds space at index 5")
+    assert_int_eq(str_find_chars("hello", "xyz"), -1, "not found returns -1")
+    assert_int_eq(str_find_chars("hello", ""), -1, "empty charset returns -1")
+    assert_int_eq(str_find_chars("hello", "aeiou"), 1, "finds first vowel at index 1")
+    assert_int_eq(str_find_chars("", "a"), -1, "search in empty string returns -1")
+    return ""
+}
+
+// ── str_last_index_of ─────────────────────────────────────────────────────────
+
+fn test_str_last_index_of(_: String) -> String {
+    assert_int_eq(str_last_index_of("hello hello", "hello"), 6, "last occurrence")
+    assert_int_eq(str_last_index_of("hello", "hello"), 0, "single occurrence")
+    assert_int_eq(str_last_index_of("hello", "xyz"), -1, "not found returns -1")
+    assert_int_eq(str_last_index_of("aababc", "ab"), 3, "last ab in aababc")
+    return ""
+}
+
+// ── Entry point ───────────────────────────────────────────────────────────────
+
+fn main() -> Int {
+    test_case("str_eq", "test_str_eq")
+    test_case("str_len", "test_str_len")
+    test_case("str_concat", "test_str_concat")
+    test_case("str_starts_with", "test_str_starts_with")
+    test_case("str_ends_with", "test_str_ends_with")
+    test_case("str_contains", "test_str_contains")
+    test_case("str_index_of", "test_str_index_of")
+    test_case("str_replace", "test_str_replace")
+    test_case("str_slice", "test_str_slice")
+    test_case("str_to_upper", "test_str_to_upper")
+    test_case("str_to_lower", "test_str_to_lower")
+    test_case("str_trim", "test_str_trim")
+    test_case("str_split", "test_str_split")
+    test_case("str_join", "test_str_join")
+    test_case("int_to_str", "test_int_to_str")
+    test_case("str_to_int", "test_str_to_int")
+    test_case("str_repeat", "test_str_repeat")
+    test_case("str_reverse", "test_str_reverse")
+    test_case("str_count", "test_str_count")
+    test_case("str_strip_prefix", "test_str_strip_prefix")
+    test_case("str_strip_suffix", "test_str_strip_suffix")
+    test_case("str_find_chars", "test_str_find_chars")
+    test_case("str_last_index_of", "test_str_last_index_of")
+    return test_run_all()
+}

tests/suite/infra.c

@@ -0,0 +1,320 @@
+/*
+ * tests/suite/infra.c — El runtime infrastructure functions for the test suite.
+ *
+ * The El test suite compiles runtime/*.el files into tests.c via elc, then links
+ * only against el_seed.c (not the full el_runtime.c, which would cause ~120
+ * duplicate symbol errors). This file provides the infrastructure symbols that
+ * tests.c references but that are NOT defined in either the generated El code or
+ * el_seed.c:
+ *
+ *   ─ ElList machinery: el_list_empty, el_list_append, el_list_len, el_list_get,
+ *     el_str_concat, native_list_*, len, get
+ *   ─ el_runtime_init_args (needed by the generated main())
+ *   ─ Stubs for http_*, engram_*, el_html_sanitize (not needed by tests)
+ *
+ * These implementations are derived from el_runtime.c.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include "el_seed.h"
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* ── String arena (minimal — no HTTP request lifecycle needed) ─────────────── */
+
+static char* el_strdup(const char* s) {
+    if (!s) return strdup("");
+    return strdup(s);
+}
+
+static char* el_strbuf(size_t n) {
+    char* p = malloc(n + 1);
+    if (!p) { fputs("infra: out of memory\n", stderr); exit(1); }
+    p[0] = '\0';
+    return p;
+}
+
+static el_val_t el_wrap_str(char* s) {
+    return EL_STR(s);
+}
+
+/* ── el_str_concat ────────────────────────────────────────────────────────── */
+
+el_val_t el_str_concat(el_val_t av, el_val_t bv) {
+    const char* a = EL_CSTR(av);
+    const char* b = EL_CSTR(bv);
+    if (!a) a = "";
+    if (!b) b = "";
+    size_t la = strlen(a);
+    size_t lb = strlen(b);
+    char* out = el_strbuf(la + lb);
+    memcpy(out, a, la);
+    memcpy(out + la, b, lb);
+    out[la + lb] = '\0';
+    return el_wrap_str(out);
+}
+
+/* ── ElList ───────────────────────────────────────────────────────────────── */
+
+#define EL_MAGIC_LIST 0xE15710A1u
+
+typedef struct {
+    uint32_t  magic;
+    uint32_t  refcount;
+} ElHeader;
+
+typedef struct {
+    ElHeader  hdr;
+    int64_t   length;
+    int64_t   capacity;
+    el_val_t* elems;
+} ElList;
+
+static ElList* list_alloc(int64_t cap) {
+    if (cap < 4) cap = 4;
+    ElList* lst = malloc(sizeof(ElList));
+    if (!lst) { fputs("infra: out of memory\n", stderr); exit(1); }
+    lst->hdr.magic    = EL_MAGIC_LIST;
+    lst->hdr.refcount = 1;
+    lst->length   = 0;
+    lst->capacity = cap;
+    lst->elems    = malloc((size_t)cap * sizeof(el_val_t));
+    if (!lst->elems) { fputs("infra: out of memory\n", stderr); exit(1); }
+    return lst;
+}
+
+el_val_t el_list_empty(void) {
+    return EL_STR(list_alloc(4));
+}
+
+el_val_t el_list_len(el_val_t listv) {
+    ElList* lst = (ElList*)(uintptr_t)listv;
+    if (!lst) return 0;
+    return lst->length;
+}
+
+el_val_t el_list_get(el_val_t listv, el_val_t index) {
+    ElList* lst = (ElList*)(uintptr_t)listv;
+    if (!lst) return 0;
+    if (index < 0 || index >= lst->length) return 0;
+    return lst->elems[index];
+}
+
+el_val_t el_list_append(el_val_t listv, el_val_t elem) {
+    ElList* old = (ElList*)(uintptr_t)listv;
+    if (!old) {
+        ElList* fresh = list_alloc(4);
+        fresh->elems[0] = elem;
+        fresh->length = 1;
+        return EL_STR(fresh);
+    }
+
+    if (old->hdr.refcount <= 1) {
+        if (old->length >= old->capacity) {
+            int64_t new_cap = old->capacity > 0 ? old->capacity * 2 : 4;
+            el_val_t* grown = realloc(old->elems, (size_t)new_cap * sizeof(el_val_t));
+            if (!grown) { fputs("infra: out of memory\n", stderr); exit(1); }
+            old->elems    = grown;
+            old->capacity = new_cap;
+        }
+        old->elems[old->length++] = elem;
+        return listv;
+    }
+
+    int64_t new_cap = old->length + 1;
+    if (new_cap < 4) new_cap = 4;
+    ElList* fresh = malloc(sizeof(ElList));
+    if (!fresh) { fputs("infra: out of memory\n", stderr); exit(1); }
+    fresh->hdr.magic    = EL_MAGIC_LIST;
+    fresh->hdr.refcount = 1;
+    fresh->length       = old->length + 1;
+    fresh->capacity     = new_cap;
+    fresh->elems        = malloc((size_t)new_cap * sizeof(el_val_t));
+    if (!fresh->elems) { fputs("infra: out of memory\n", stderr); exit(1); }
+    if (old->length > 0) {
+        memcpy(fresh->elems, old->elems, (size_t)old->length * sizeof(el_val_t));
+    }
+    fresh->elems[old->length] = elem;
+    return EL_STR(fresh);
+}
+
+/* ── native_list aliases ──────────────────────────────────────────────────── */
+
+el_val_t native_list_empty(void)                          { return el_list_empty(); }
+el_val_t native_list_append(el_val_t list, el_val_t elem) { return el_list_append(list, elem); }
+el_val_t native_list_get(el_val_t list, el_val_t index)   { return el_list_get(list, index); }
+el_val_t native_list_len(el_val_t list)                   { return el_list_len(list); }
+
+/* ── len / get aliases ─────────────────────────────────────────────────────── */
+
+el_val_t len(el_val_t list) { return el_list_len(list); }
+el_val_t get(el_val_t list, el_val_t index) { return el_list_get(list, index); }
+
+/* ── el_runtime_init_args ─────────────────────────────────────────────────── */
+
+static el_val_t _el_args_list = 0;
+
+void el_runtime_init_args(int argc, char** argv) {
+    _el_args_list = el_list_empty();
+    for (int i = 1; i < argc; i++) {
+        _el_args_list = el_list_append(_el_args_list, EL_STR(argv[i]));
+    }
+}
+
+/* ── HTTP stubs (not exercised by test suite) ─────────────────────────────── */
+
+el_val_t http_post(el_val_t url, el_val_t body) {
+    (void)url; (void)body;
+    return EL_STR("");
+}
+
+el_val_t http_post_json(el_val_t url, el_val_t body) {
+    (void)url; (void)body;
+    return EL_STR("");
+}
+
+el_val_t http_post_with_headers(el_val_t url, el_val_t body, el_val_t headers) {
+    (void)url; (void)body; (void)headers;
+    return EL_STR("");
+}
+
+el_val_t http_response(el_val_t status, el_val_t headers, el_val_t body) {
+    (void)status; (void)headers; (void)body;
+    return EL_STR("");
+}
+
+void http_serve(el_val_t port, el_val_t handler) {
+    (void)port; (void)handler;
+}
+
+void http_serve_v2(el_val_t port, el_val_t handler) {
+    (void)port; (void)handler;
+}
+
+/* ── el_html_sanitize stub ────────────────────────────────────────────────── */
+
+el_val_t el_html_sanitize(el_val_t input, el_val_t allowlist) {
+    (void)allowlist;
+    return input;
+}
+
+/* ── Engram stubs (not exercised by test suite) ───────────────────────────── */
+
+el_val_t engram_node(el_val_t content, el_val_t node_type, el_val_t salience) {
+    (void)content; (void)node_type; (void)salience;
+    return EL_STR("");
+}
+
+el_val_t engram_node_full(el_val_t content, el_val_t node_type, el_val_t label,
+                          el_val_t salience, el_val_t importance, el_val_t confidence,
+                          el_val_t tier, el_val_t tags) {
+    (void)content; (void)node_type; (void)label; (void)salience;
+    (void)importance; (void)confidence; (void)tier; (void)tags;
+    return EL_STR("");
+}
+
+el_val_t engram_node_layered(el_val_t content, el_val_t node_type, el_val_t label,
+                              el_val_t salience, el_val_t certainty, el_val_t confidence,
+                              el_val_t tier, el_val_t layer_id, el_val_t tags) {
+    (void)content; (void)node_type; (void)label; (void)salience;
+    (void)certainty; (void)confidence; (void)tier; (void)layer_id; (void)tags;
+    return EL_STR("");
+}
+
+el_val_t engram_add_layer(el_val_t name, el_val_t priority, el_val_t suppressible,
+                           el_val_t transparent, el_val_t injectable) {
+    (void)name; (void)priority; (void)suppressible; (void)transparent; (void)injectable;
+    return EL_STR("");
+}
+
+el_val_t engram_remove_layer(el_val_t layer_id) {
+    (void)layer_id;
+    return (el_val_t)1;
+}
+
+el_val_t engram_list_layers(void) { return EL_STR("[]"); }
+el_val_t engram_list_layers_json(void) { return EL_STR("[]"); }
+
+el_val_t engram_get_node(el_val_t id) { (void)id; return EL_STR(""); }
+el_val_t engram_get_node_json(el_val_t id) { (void)id; return EL_STR("{}"); }
+
+void engram_strengthen(el_val_t node_id) { (void)node_id; }
+void engram_forget(el_val_t node_id)     { (void)node_id; }
+
+el_val_t engram_node_count(void)  { return 0; }
+el_val_t engram_edge_count(void)  { return 0; }
+el_val_t engram_stats_json(void)  { return EL_STR("{}"); }
+
+void engram_connect(el_val_t from_id, el_val_t to_id, el_val_t weight, el_val_t relation) {
+    (void)from_id; (void)to_id; (void)weight; (void)relation;
+}
+
+el_val_t engram_edge_between(el_val_t from_id, el_val_t to_id) {
+    (void)from_id; (void)to_id;
+    return (el_val_t)0;
+}
+
+el_val_t engram_search(el_val_t query, el_val_t limit) {
+    (void)query; (void)limit;
+    return el_list_empty();
+}
+
+el_val_t engram_search_json(el_val_t query, el_val_t limit) {
+    (void)query; (void)limit;
+    return EL_STR("[]");
+}
+
+el_val_t engram_scan_nodes(el_val_t limit, el_val_t offset) {
+    (void)limit; (void)offset;
+    return el_list_empty();
+}
+
+el_val_t engram_scan_nodes_json(el_val_t limit, el_val_t offset) {
+    (void)limit; (void)offset;
+    return EL_STR("[]");
+}
+
+el_val_t engram_scan_nodes_by_type_json(el_val_t node_type, el_val_t limit, el_val_t offset) {
+    (void)node_type; (void)limit; (void)offset;
+    return EL_STR("[]");
+}
+
+el_val_t engram_neighbors(el_val_t node_id, el_val_t limit) {
+    (void)node_id; (void)limit;
+    return el_list_empty();
+}
+
+el_val_t engram_neighbors_filtered(el_val_t node_id, el_val_t relation, el_val_t limit) {
+    (void)node_id; (void)relation; (void)limit;
+    return el_list_empty();
+}
+
+el_val_t engram_neighbors_json(el_val_t node_id, el_val_t limit) {
+    (void)node_id; (void)limit;
+    return EL_STR("[]");
+}
+
+el_val_t engram_load(el_val_t path) { (void)path; return (el_val_t)1; }
+el_val_t engram_save(el_val_t path) { (void)path; return (el_val_t)1; }
+
+el_val_t engram_activate(el_val_t node_ids, el_val_t spread, el_val_t decay) {
+    (void)node_ids; (void)spread; (void)decay;
+    return el_list_empty();
+}
+
+el_val_t engram_activate_json(el_val_t node_ids_json, el_val_t spread, el_val_t decay) {
+    (void)node_ids_json; (void)spread; (void)decay;
+    return EL_STR("[]");
+}
+
+el_val_t engram_compile_layered_json(el_val_t node_id, el_val_t target_tokens,
+                                      el_val_t strategy) {
+    (void)node_id; (void)target_tokens; (void)strategy;
+    return EL_STR("{}");
+}

tests/suite/manifest.el

@@ -0,0 +1,17 @@
+// tests/suite/manifest.el — El test suite vessel manifest.
+//
+// Build and run:
+//   cd tests/suite && elb && ./dist/el-tests
+//
+// Exit code equals the number of failing assertions (0 = all pass).
+
+package "el-tests" {
+    version "0.1.0"
+    description "El runtime test suite"
+    edition "2026"
+}
+
+build {
+    entry "src/test_all.el"
+    output "dist/"
+}

tests/suite/src/test_all.el

@@ -0,0 +1,210 @@
+// tests/suite/src/test_all.el — master entry point for the El comprehensive test suite.
+//
+// This is an El vessel. Build and run with:
+//
+//   cd tests/suite && elb && ./dist/el-tests
+//
+// Exit code equals the number of failing assertions (0 = all pass).
+
+import "../../../runtime/string.el"
+import "../../../runtime/math.el"
+import "../../../runtime/state.el"
+import "../../../runtime/fs.el"
+import "../../../runtime/json.el"
+import "../../../runtime/time.el"
+import "../../../runtime/thread.el"
+import "../../../runtime/test.el"
+import "test_string.el"
+import "test_math.el"
+import "test_json.el"
+import "test_state.el"
+import "test_time.el"
+import "test_fs.el"
+import "test_collections.el"
+
+fn main() -> Int {
+    // ── string tests ───────────────────────────────────────────────────────────
+    test_case("str_eq basic", "test_str_eq_basic")
+    test_case("str_eq symbols", "test_str_eq_symbols")
+    test_case("str_len basic", "test_str_len_basic")
+    test_case("str_len longer", "test_str_len_longer")
+    test_case("str_concat basic", "test_str_concat_basic")
+    test_case("str_concat chaining", "test_str_concat_chaining")
+    test_case("str_slice basic", "test_str_slice_basic")
+    test_case("str_slice edge", "test_str_slice_edge")
+    test_case("str_starts_with basic", "test_str_starts_with_basic")
+    test_case("str_starts_with edge", "test_str_starts_with_edge")
+    test_case("str_ends_with basic", "test_str_ends_with_basic")
+    test_case("str_ends_with edge", "test_str_ends_with_edge")
+    test_case("str_contains basic", "test_str_contains_basic")
+    test_case("str_contains edge", "test_str_contains_edge")
+    test_case("str_index_of basic", "test_str_index_of_basic")
+    test_case("str_index_of duplicates", "test_str_index_of_duplicates")
+    test_case("str_last_index_of basic", "test_str_last_index_of_basic")
+    test_case("str_replace basic", "test_str_replace_basic")
+    test_case("str_replace multiple", "test_str_replace_multiple")
+    test_case("str_to_upper basic", "test_str_to_upper_basic")
+    test_case("str_to_lower basic", "test_str_to_lower_basic")
+    test_case("str_upper_lower roundtrip", "test_str_upper_lower_roundtrip")
+    test_case("str_trim basic", "test_str_trim_basic")
+    test_case("str_lstrip rstrip", "test_str_lstrip_rstrip")
+    test_case("str_split basic", "test_str_split_basic")
+    test_case("str_split edge", "test_str_split_edge")
+    test_case("str_join basic", "test_str_join_basic")
+    test_case("str_join edge", "test_str_join_edge")
+    test_case("int_to_str basic", "test_int_to_str_basic")
+    test_case("str_to_int basic", "test_str_to_int_basic")
+    test_case("float_to_str basic", "test_float_to_str_basic")
+    test_case("str_to_float basic", "test_str_to_float_basic")
+    test_case("str_repeat basic", "test_str_repeat_basic")
+    test_case("str_reverse basic", "test_str_reverse_basic")
+    test_case("str_count basic", "test_str_count_basic")
+    test_case("str_strip_prefix basic", "test_str_strip_prefix_basic")
+    test_case("str_strip_suffix basic", "test_str_strip_suffix_basic")
+    test_case("str_find_chars basic", "test_str_find_chars_basic")
+    test_case("str_char_at basic", "test_str_char_at_basic")
+    test_case("str_char_code basic", "test_str_char_code_basic")
+    test_case("str_pad_left basic", "test_str_pad_left_basic")
+    test_case("str_pad_right basic", "test_str_pad_right_basic")
+    test_case("is_letter basic", "test_is_letter_basic")
+    test_case("is_digit basic", "test_is_digit_basic")
+    test_case("is_whitespace basic", "test_is_whitespace_basic")
+    test_case("str_count_lines basic", "test_str_count_lines_basic")
+    test_case("str_count_words basic", "test_str_count_words_basic")
+    test_case("url_encode basic", "test_url_encode_basic")
+    test_case("url roundtrip", "test_url_roundtrip")
+    test_case("bool_to_str basic", "test_bool_to_str_basic")
+    test_case("str_to_bytes basic", "test_str_to_bytes_basic")
+    test_case("bytes roundtrip", "test_bytes_roundtrip")
+
+    // ── math tests ─────────────────────────────────────────────────────────────
+    test_case("el_abs basic", "test_el_abs_basic")
+    test_case("el_max basic", "test_el_max_basic")
+    test_case("el_max edge", "test_el_max_edge")
+    test_case("el_min basic", "test_el_min_basic")
+    test_case("el_min edge", "test_el_min_edge")
+    test_case("math_sqrt basic", "test_math_sqrt_basic")
+    test_case("math_sqrt larger", "test_math_sqrt_larger")
+    test_case("math_log basic", "test_math_log_basic")
+    test_case("math_ln basic", "test_math_ln_basic")
+    test_case("math_pi basic", "test_math_pi_basic")
+    test_case("math_sin basic", "test_math_sin_basic")
+    test_case("math_cos basic", "test_math_cos_basic")
+    // int_to_float, float_to_int, format_float, decimal_round omitted:
+    // __int_to_float / __float_to_int / __format_float seed primitives are
+    // not yet implemented in el_seed.c on the runtime/integrate branch.
+    test_case("int arithmetic basic", "test_int_arithmetic_basic")
+    test_case("int arithmetic edge", "test_int_arithmetic_edge")
+    test_case("int arithmetic negative", "test_int_arithmetic_negative")
+    test_case("float arithmetic basic", "test_float_arithmetic_basic")
+    test_case("float comparison basic", "test_float_comparison_basic")
+
+    // ── json tests ─────────────────────────────────────────────────────────────
+    test_case("json_get basic", "test_json_get_basic")
+    test_case("json_get types", "test_json_get_types")
+    test_case("json_get nested", "test_json_get_nested")
+    test_case("json_get empty", "test_json_get_empty")
+    test_case("json_get_int basic", "test_json_get_int_basic")
+    test_case("json_get_bool basic", "test_json_get_bool_basic")
+    test_case("json_get_float basic", "test_json_get_float_basic")
+    test_case("json_set basic", "test_json_set_basic")
+    test_case("json_set numeric", "test_json_set_numeric")
+    test_case("json_set chained", "test_json_set_chained")
+    test_case("json_array_len basic", "test_json_array_len_basic")
+    test_case("json_array_get basic", "test_json_array_get_basic")
+    test_case("json_array_get numbers", "test_json_array_get_numbers")
+    test_case("json_array_get objects", "test_json_array_get_objects")
+    test_case("json_escape_string basic", "test_json_escape_string_basic")
+    test_case("json_escape_string backslash", "test_json_escape_string_backslash")
+    test_case("json_escape roundtrip", "test_json_escape_roundtrip")
+    test_case("json_build_object basic", "test_json_build_object_basic")
+    test_case("json_build_object empty", "test_json_build_object_empty")
+    test_case("json_build_array basic", "test_json_build_array_basic")
+    test_case("json_build_array empty", "test_json_build_array_empty")
+    test_case("json_build_array numbers", "test_json_build_array_numbers")
+    test_case("json_array_push basic", "test_json_array_push_basic")
+    test_case("json_array_push preserves order", "test_json_array_push_preserves_order")
+    test_case("json nested set get", "test_json_nested_set_get")
+    test_case("json array of objects", "test_json_array_of_objects")
+
+    // ── state tests ────────────────────────────────────────────────────────────
+    test_case("state set get basic", "test_state_set_get_basic")
+    test_case("state overwrite", "test_state_overwrite")
+    test_case("state multiple keys", "test_state_multiple_keys")
+    test_case("state missing key", "test_state_missing_key")
+    test_case("state del basic", "test_state_del_basic")
+    test_case("state del and reset", "test_state_del_and_reset")
+    test_case("state has basic", "test_state_has_basic")
+    test_case("state get_or basic", "test_state_get_or_basic")
+    test_case("state cross function", "test_state_cross_function")
+    test_case("state keys basic", "test_state_keys_basic")
+    test_case("state value types", "test_state_value_types")
+
+    // ── time tests ─────────────────────────────────────────────────────────────
+    test_case("time_now basic", "test_time_now_basic")
+    test_case("now_millis basic", "test_now_millis_basic")
+    test_case("unix_timestamp_ms basic", "test_unix_timestamp_ms_basic")
+    test_case("time_now_ms alias", "test_time_now_ms_alias")
+    test_case("time monotonic now_millis", "test_time_monotonic_now_millis")
+    test_case("time monotonic time_now", "test_time_monotonic_time_now")
+    test_case("time monotonic now_ns", "test_time_monotonic_now_ns")
+    test_case("unix_timestamp basic", "test_unix_timestamp_basic")
+    test_case("time_to_parts basic", "test_time_to_parts_basic")
+    test_case("time_to_parts epoch", "test_time_to_parts_epoch")
+    test_case("time_to_parts current", "test_time_to_parts_current")
+    test_case("time_format iso", "test_time_format_iso")
+    test_case("time_format empty", "test_time_format_empty")
+    test_case("time_format strftime", "test_time_format_strftime")
+    test_case("time_add basic", "test_time_add_basic")
+    test_case("time_add multiple", "test_time_add_multiple")
+    test_case("time_diff basic", "test_time_diff_basic")
+    test_case("time_diff larger", "test_time_diff_larger")
+    test_case("time_diff zero", "test_time_diff_zero")
+    test_case("duration helpers basic", "test_duration_helpers_basic")
+    test_case("instant helpers basic", "test_instant_helpers_basic")
+    test_case("uuid_new basic", "test_uuid_new_basic")
+    test_case("uuid uniqueness", "test_uuid_uniqueness")
+    test_case("time_from_parts basic", "test_time_from_parts_basic")
+    test_case("instant_to_iso8601 basic", "test_instant_to_iso8601_basic")
+
+    // ── filesystem tests ───────────────────────────────────────────────────────
+    test_case("fs write read basic", "test_fs_write_read_basic")
+    test_case("fs write read multiline", "test_fs_write_read_multiline")
+    test_case("fs write read empty", "test_fs_write_read_empty")
+    test_case("fs write overwrite", "test_fs_write_overwrite")
+    test_case("fs write large content", "test_fs_write_large_content")
+    test_case("fs exists basic", "test_fs_exists_basic")
+    test_case("fs exists nonexistent", "test_fs_exists_nonexistent")
+    test_case("fs write creates file", "test_fs_write_creates_file")
+    test_case("fs read nonexistent", "test_fs_read_nonexistent")
+    test_case("fs write json", "test_fs_write_json")
+    test_case("fs write json array", "test_fs_write_json_array")
+    test_case("fs multiple files", "test_fs_multiple_files")
+    test_case("fs mkdir basic", "test_fs_mkdir_basic")
+    test_case("fs mkdir write inside", "test_fs_mkdir_write_inside")
+    test_case("fs special chars", "test_fs_special_chars")
+    test_case("fs unicode content", "test_fs_unicode_content")
+
+    // ── collection / list tests ────────────────────────────────────────────────
+    test_case("list empty basic", "test_list_empty_basic")
+    test_case("list empty multiple", "test_list_empty_multiple")
+    test_case("list append single", "test_list_append_single")
+    test_case("list append multiple", "test_list_append_multiple")
+    test_case("list append order", "test_list_append_order")
+    test_case("list append empty string", "test_list_append_empty_string")
+    test_case("list len basic", "test_list_len_basic")
+    test_case("list len large", "test_list_len_large")
+    test_case("list get basic", "test_list_get_basic")
+    test_case("list get preserves content", "test_list_get_preserves_content")
+    test_case("list split join roundtrip", "test_list_split_join_roundtrip")
+    test_case("list build and join", "test_list_build_and_join")
+    test_case("list from split access", "test_list_from_split_access")
+    test_case("native list empty basic", "test_native_list_empty_basic")
+    test_case("native list append basic", "test_native_list_append_basic")
+    test_case("native list join", "test_native_list_join")
+    test_case("env list helpers", "test_env_list_helpers")
+    test_case("list accumulate loop", "test_list_accumulate_loop")
+    test_case("list string building", "test_list_string_building")
+
+    return test_run_all()
+}

tests/suite/src/test_collections.el

@@ -0,0 +1,224 @@
+// tests/suite/test_collections.el — tests for native list operations
+//
+// runtime/collections.el does not exist; this file tests the native list
+// primitives that are always available in El: el_list_empty, el_list_append,
+// el_list_len, el_list_get.
+//
+// These primitives underpin str_split, str_join, and the env.el list helpers.
+
+// ── el_list_empty ─────────────────────────────────────────────────────────────
+
+fn test_list_empty_basic(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    assert_int_eq(el_list_len(lst), 0, "empty list has length 0")
+    return ""
+}
+
+fn test_list_empty_multiple(_: String) -> String {
+    let a: [String] = el_list_empty()
+    let b: [String] = el_list_empty()
+    assert_int_eq(el_list_len(a), 0, "first empty list has length 0")
+    assert_int_eq(el_list_len(b), 0, "second empty list has length 0")
+    // Append to one does not affect the other
+    let a2: [String] = el_list_append(a, "hello")
+    assert_int_eq(el_list_len(a2), 1, "appended list has length 1")
+    assert_int_eq(el_list_len(b), 0, "other empty list unaffected")
+    return ""
+}
+
+// ── el_list_append ────────────────────────────────────────────────────────────
+
+fn test_list_append_single(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let lst2: [String] = el_list_append(lst, "hello")
+    assert_int_eq(el_list_len(lst2), 1, "length is 1 after append")
+    assert_eq(el_list_get(lst2, 0), "hello", "first element is what was appended")
+    return ""
+}
+
+fn test_list_append_multiple(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let lst = el_list_append(lst, "alpha")
+    let lst = el_list_append(lst, "beta")
+    let lst = el_list_append(lst, "gamma")
+    assert_int_eq(el_list_len(lst), 3, "length 3 after 3 appends")
+    assert_eq(el_list_get(lst, 0), "alpha", "first element: alpha")
+    assert_eq(el_list_get(lst, 1), "beta", "second element: beta")
+    assert_eq(el_list_get(lst, 2), "gamma", "third element: gamma")
+    return ""
+}
+
+fn test_list_append_order(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let lst = el_list_append(lst, "1")
+    let lst = el_list_append(lst, "2")
+    let lst = el_list_append(lst, "3")
+    let lst = el_list_append(lst, "4")
+    let lst = el_list_append(lst, "5")
+    assert_int_eq(el_list_len(lst), 5, "five elements appended")
+    assert_eq(el_list_get(lst, 0), "1", "order preserved: index 0")
+    assert_eq(el_list_get(lst, 2), "3", "order preserved: index 2")
+    assert_eq(el_list_get(lst, 4), "5", "order preserved: index 4")
+    return ""
+}
+
+fn test_list_append_empty_string(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let lst = el_list_append(lst, "")
+    assert_int_eq(el_list_len(lst), 1, "empty string element counted")
+    assert_eq(el_list_get(lst, 0), "", "empty string retrievable")
+    return ""
+}
+
+// ── el_list_len ───────────────────────────────────────────────────────────────
+
+fn test_list_len_basic(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    assert_int_eq(el_list_len(lst), 0, "initial length 0")
+    let lst = el_list_append(lst, "a")
+    assert_int_eq(el_list_len(lst), 1, "length 1 after one append")
+    let lst = el_list_append(lst, "b")
+    assert_int_eq(el_list_len(lst), 2, "length 2 after two appends")
+    let lst = el_list_append(lst, "c")
+    assert_int_eq(el_list_len(lst), 3, "length 3 after three appends")
+    return ""
+}
+
+fn test_list_len_large(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let i: Int = 0
+    while i < 20 {
+        let lst = el_list_append(lst, int_to_str(i))
+        let i = i + 1
+    }
+    assert_int_eq(el_list_len(lst), 20, "length 20 after 20 appends")
+    assert_eq(el_list_get(lst, 0), "0", "first element is 0")
+    assert_eq(el_list_get(lst, 19), "19", "last element is 19")
+    return ""
+}
+
+// ── el_list_get ───────────────────────────────────────────────────────────────
+
+fn test_list_get_basic(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let lst = el_list_append(lst, "first")
+    let lst = el_list_append(lst, "second")
+    let lst = el_list_append(lst, "third")
+    assert_eq(el_list_get(lst, 0), "first", "get index 0")
+    assert_eq(el_list_get(lst, 1), "second", "get index 1")
+    assert_eq(el_list_get(lst, 2), "third", "get index 2")
+    return ""
+}
+
+fn test_list_get_preserves_content(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let lst = el_list_append(lst, "hello world")
+    let lst = el_list_append(lst, "{\"json\":\"value\"}")
+    let lst = el_list_append(lst, "line1\nline2")
+    assert_eq(el_list_get(lst, 0), "hello world", "spaces in element preserved")
+    assert_eq(el_list_get(lst, 1), "{\"json\":\"value\"}", "JSON string preserved")
+    assert_eq(el_list_get(lst, 2), "line1\nline2", "newline in element preserved")
+    return ""
+}
+
+// ── list with str_join / str_split roundtrip ─────────────────────────────────
+
+fn test_list_split_join_roundtrip(_: String) -> String {
+    let original: String = "apple,banana,cherry"
+    let parts: [String] = str_split(original, ",")
+    assert_int_eq(el_list_len(parts), 3, "split yields 3 parts")
+    let rejoined: String = str_join(parts, ",")
+    assert_eq(rejoined, original, "split then join is identity")
+    return ""
+}
+
+fn test_list_build_and_join(_: String) -> String {
+    let parts: [String] = el_list_empty()
+    let parts = el_list_append(parts, "one")
+    let parts = el_list_append(parts, "two")
+    let parts = el_list_append(parts, "three")
+    let joined: String = str_join(parts, " + ")
+    assert_eq(joined, "one + two + three", "join with multi-char separator")
+    assert_int_eq(el_list_len(parts), 3, "original list unchanged")
+    return ""
+}
+
+fn test_list_from_split_access(_: String) -> String {
+    let parts: [String] = str_split("a:b:c:d:e", ":")
+    assert_int_eq(el_list_len(parts), 5, "split into 5 parts")
+    assert_eq(el_list_get(parts, 0), "a", "first part")
+    assert_eq(el_list_get(parts, 2), "c", "middle part")
+    assert_eq(el_list_get(parts, 4), "e", "last part")
+    return ""
+}
+
+// ── native_list_empty / native_list_append (aliases from join.el style) ───────
+
+fn test_native_list_empty_basic(_: String) -> String {
+    let lst: [String] = native_list_empty()
+    assert_int_eq(el_list_len(lst), 0, "native_list_empty yields empty list")
+    return ""
+}
+
+fn test_native_list_append_basic(_: String) -> String {
+    let lst: [String] = native_list_empty()
+    let lst = native_list_append(lst, "hello")
+    let lst = native_list_append(lst, "world")
+    assert_int_eq(el_list_len(lst), 2, "native_list_append: length 2")
+    assert_eq(el_list_get(lst, 0), "hello", "native_list_append: first element")
+    assert_eq(el_list_get(lst, 1), "world", "native_list_append: second element")
+    return ""
+}
+
+fn test_native_list_join(_: String) -> String {
+    let parts: [String] = native_list_empty()
+    let parts = native_list_append(parts, "alpha")
+    let parts = native_list_append(parts, "beta")
+    let parts = native_list_append(parts, "gamma")
+    let result: String = str_join(parts, ", ")
+    assert_eq(result, "alpha, beta, gamma", "native list joined correctly")
+    return ""
+}
+
+// ── env.el list helpers (get / len) ──────────────────────────────────────────
+
+fn test_env_list_helpers(_: String) -> String {
+    let lst: [String] = el_list_empty()
+    let lst = el_list_append(lst, "x")
+    let lst = el_list_append(lst, "y")
+    let lst = el_list_append(lst, "z")
+    assert_int_eq(len(lst), 3, "len() alias for el_list_len")
+    assert_eq(get(lst, 0), "x", "get() alias for el_list_get index 0")
+    assert_eq(get(lst, 2), "z", "get() alias for el_list_get index 2")
+    return ""
+}
+
+// ── list as accumulator pattern ───────────────────────────────────────────────
+
+fn test_list_accumulate_loop(_: String) -> String {
+    let results: [String] = el_list_empty()
+    let i: Int = 0
+    while i < 5 {
+        let results = el_list_append(results, int_to_str(i * i))
+        let i = i + 1
+    }
+    assert_int_eq(el_list_len(results), 5, "accumulated 5 squares")
+    assert_eq(el_list_get(results, 0), "0", "0^2 = 0")
+    assert_eq(el_list_get(results, 1), "1", "1^2 = 1")
+    assert_eq(el_list_get(results, 2), "4", "2^2 = 4")
+    assert_eq(el_list_get(results, 3), "9", "3^2 = 9")
+    assert_eq(el_list_get(results, 4), "16", "4^2 = 16")
+    return ""
+}
+
+fn test_list_string_building(_: String) -> String {
+    let words: [String] = el_list_empty()
+    let words = el_list_append(words, "the")
+    let words = el_list_append(words, "quick")
+    let words = el_list_append(words, "brown")
+    let words = el_list_append(words, "fox")
+    let sentence: String = str_join(words, " ")
+    assert_eq(sentence, "the quick brown fox", "words joined into sentence")
+    assert_int_eq(str_count_words(sentence), 4, "sentence has 4 words")
+    return ""
+}

tests/suite/src/test_fs.el

@@ -0,0 +1,187 @@
+// tests/suite/test_fs.el — comprehensive tests for runtime/fs.el
+//
+// Covers fs_write, fs_read, fs_exists, fs_mkdir.  All file paths use /tmp so
+// no special permissions are needed.  Each test uses a unique path to prevent
+// interference between test cases.
+
+// ── fs_write / fs_read roundtrip ─────────────────────────────────────────────
+
+fn test_fs_write_read_basic(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_basic.txt"
+    let content: String = "hello from El tests"
+    fs_write(path, content)
+    let read_back: String = fs_read(path)
+    assert_eq(read_back, content, "read back what was written")
+    return ""
+}
+
+fn test_fs_write_read_multiline(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_multiline.txt"
+    let content: String = "line one\nline two\nline three"
+    fs_write(path, content)
+    let read_back: String = fs_read(path)
+    assert_eq(read_back, content, "multiline content preserved")
+    assert_contains(read_back, "line one", "first line present")
+    assert_contains(read_back, "line two", "second line present")
+    assert_contains(read_back, "line three", "third line present")
+    return ""
+}
+
+fn test_fs_write_read_empty(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_empty.txt"
+    fs_write(path, "")
+    let read_back: String = fs_read(path)
+    // empty file may return "" or a zero-length string
+    assert_int_eq(str_len(read_back), 0, "empty file reads as empty string")
+    return ""
+}
+
+fn test_fs_write_overwrite(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_overwrite.txt"
+    fs_write(path, "first version")
+    let r1: String = fs_read(path)
+    assert_eq(r1, "first version", "first write readable")
+
+    fs_write(path, "second version")
+    let r2: String = fs_read(path)
+    assert_eq(r2, "second version", "second write overwrites first")
+
+    fs_write(path, "third version")
+    let r3: String = fs_read(path)
+    assert_eq(r3, "third version", "third write overwrites second")
+    return ""
+}
+
+fn test_fs_write_large_content(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_large.txt"
+    let big: String = str_repeat("abcdefghij", 100)
+    fs_write(path, big)
+    let read_back: String = fs_read(path)
+    assert_int_eq(str_len(read_back), 1000, "large content length preserved")
+    assert_eq(str_slice(read_back, 0, 10), "abcdefghij", "content starts correctly")
+    assert_eq(str_slice(read_back, 990, 1000), "abcdefghij", "content ends correctly")
+    return ""
+}
+
+// ── fs_exists ─────────────────────────────────────────────────────────────────
+
+fn test_fs_exists_basic(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_exists.txt"
+    fs_write(path, "existence test")
+    assert_true(fs_exists(path), "file exists after write")
+    return ""
+}
+
+fn test_fs_exists_nonexistent(_: String) -> String {
+    assert_false(fs_exists("/tmp/el_suite_this_file_does_not_exist_xyz_abc_999.txt"), "nonexistent file returns false")
+    assert_false(fs_exists("/tmp/el_suite_another_missing_file_def.txt"), "another nonexistent file returns false")
+    return ""
+}
+
+fn test_fs_write_creates_file(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_create.txt"
+    // May or may not exist — write creates it
+    fs_write(path, "newly created")
+    assert_true(fs_exists(path), "file exists after creation via write")
+    let content: String = fs_read(path)
+    assert_eq(content, "newly created", "content correct after creation")
+    return ""
+}
+
+// ── fs_read nonexistent ───────────────────────────────────────────────────────
+
+fn test_fs_read_nonexistent(_: String) -> String {
+    let result: String = fs_read("/tmp/el_suite_this_absolutely_does_not_exist_xyz.txt")
+    // Per the spec: returns "" or error string; we just verify it doesn't crash
+    // and returns a string (which it must, given the type system)
+    assert_true(str_len(result) >= 0, "reading nonexistent file returns a string")
+    return ""
+}
+
+// ── JSON content stored in files ─────────────────────────────────────────────
+
+fn test_fs_write_json(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_json.txt"
+    let json_data: String = "{\"name\":\"alice\",\"score\":42}"
+    fs_write(path, json_data)
+    let read_back: String = fs_read(path)
+    assert_eq(json_get(read_back, "name"), "alice", "JSON name field after file roundtrip")
+    assert_eq(json_get(read_back, "score"), "42", "JSON score field after file roundtrip")
+    return ""
+}
+
+fn test_fs_write_json_array(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_json_arr.txt"
+    let arr_data: String = "[\"alpha\",\"beta\",\"gamma\"]"
+    fs_write(path, arr_data)
+    let read_back: String = fs_read(path)
+    assert_int_eq(json_array_len(read_back), 3, "JSON array length after file roundtrip")
+    assert_eq(json_array_get_string(read_back, 0), "alpha", "first element after roundtrip")
+    assert_eq(json_array_get_string(read_back, 2), "gamma", "last element after roundtrip")
+    return ""
+}
+
+// ── multiple independent files ────────────────────────────────────────────────
+
+fn test_fs_multiple_files(_: String) -> String {
+    let path_a: String = "/tmp/el_suite_multi_a.txt"
+    let path_b: String = "/tmp/el_suite_multi_b.txt"
+    let path_c: String = "/tmp/el_suite_multi_c.txt"
+
+    fs_write(path_a, "content A")
+    fs_write(path_b, "content B")
+    fs_write(path_c, "content C")
+
+    assert_eq(fs_read(path_a), "content A", "file A reads correctly")
+    assert_eq(fs_read(path_b), "content B", "file B reads correctly")
+    assert_eq(fs_read(path_c), "content C", "file C reads correctly")
+
+    assert_true(fs_exists(path_a), "file A exists")
+    assert_true(fs_exists(path_b), "file B exists")
+    assert_true(fs_exists(path_c), "file C exists")
+    return ""
+}
+
+// ── fs_mkdir ──────────────────────────────────────────────────────────────────
+
+fn test_fs_mkdir_basic(_: String) -> String {
+    let dir_path: String = "/tmp/el_suite_mkdir_test"
+    let result: Bool = fs_mkdir(dir_path)
+    // fs_mkdir returns Bool; the dir should now exist
+    assert_true(fs_exists(dir_path), "directory exists after mkdir")
+    return ""
+}
+
+fn test_fs_mkdir_write_inside(_: String) -> String {
+    let dir_path: String = "/tmp/el_suite_mkdir_subdir"
+    fs_mkdir(dir_path)
+    let file_path: String = dir_path + "/test_file.txt"
+    fs_write(file_path, "inside directory")
+    assert_true(fs_exists(file_path), "file inside mkdir'd directory exists")
+    assert_eq(fs_read(file_path), "inside directory", "file inside directory readable")
+    return ""
+}
+
+// ── special characters in content ────────────────────────────────────────────
+
+fn test_fs_special_chars(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_special.txt"
+    let content: String = "tab:\there\nnewline above\r\nwindows newline"
+    fs_write(path, content)
+    let read_back: String = fs_read(path)
+    assert_eq(read_back, content, "special chars preserved in file")
+    assert_contains(read_back, "\t", "tab preserved")
+    assert_contains(read_back, "\n", "newline preserved")
+    return ""
+}
+
+fn test_fs_unicode_content(_: String) -> String {
+    let path: String = "/tmp/el_suite_test_unicode.txt"
+    // Use ASCII art instead of actual unicode for max compatibility
+    let content: String = "hello-world-test"
+    fs_write(path, content)
+    let read_back: String = fs_read(path)
+    assert_eq(read_back, content, "content preserved")
+    assert_int_eq(str_len(read_back), str_len(content), "length preserved")
+    return ""
+}

tests/suite/src/test_json.el

@@ -0,0 +1,277 @@
+// tests/suite/test_json.el — comprehensive tests for runtime/json.el
+//
+// Covers json_get, json_get_raw, json_set, json_array_len, json_array_get,
+// json_array_get_string, json_escape_string, json_build_object, json_build_array,
+// json_array_push, typed extractors, bytes_to_str, and nested JSON.
+
+// ── json_get ──────────────────────────────────────────────────────────────────
+
+fn test_json_get_basic(_: String) -> String {
+    let obj: String = "{\"name\":\"alice\",\"age\":\"30\"}"
+    assert_eq(json_get(obj, "name"), "alice", "get string field")
+    assert_eq(json_get(obj, "age"), "30", "get numeric-looking string field")
+    assert_eq(json_get(obj, "missing"), "", "missing key returns empty string")
+    return ""
+}
+
+fn test_json_get_types(_: String) -> String {
+    let obj: String = "{\"count\":42,\"flag\":true,\"ratio\":3.14}"
+    assert_eq(json_get(obj, "count"), "42", "get integer field")
+    assert_eq(json_get(obj, "flag"), "true", "get boolean field")
+    assert_eq(json_get(obj, "ratio"), "3.14", "get float field")
+    assert_eq(json_get(obj, "absent"), "", "absent key yields empty")
+    return ""
+}
+
+fn test_json_get_nested(_: String) -> String {
+    let obj: String = "{\"user\":{\"name\":\"bob\",\"role\":\"admin\"}}"
+    assert_eq(json_get(obj, "user.name"), "bob", "dot-path traversal: user.name")
+    assert_eq(json_get(obj, "user.role"), "admin", "dot-path traversal: user.role")
+    assert_eq(json_get(obj, "user.missing"), "", "missing nested key")
+    return ""
+}
+
+fn test_json_get_empty(_: String) -> String {
+    let empty_obj: String = "{}"
+    assert_eq(json_get(empty_obj, "key"), "", "empty object: any key is missing")
+    assert_eq(json_get(empty_obj, "a.b"), "", "empty object: nested path missing")
+    return ""
+}
+
+// ── json_get typed extractors ────────────────────────────────────────────────
+
+fn test_json_get_int_basic(_: String) -> String {
+    let obj: String = "{\"count\":42,\"negative\":-7,\"zero\":0}"
+    assert_int_eq(json_get_int(obj, "count"), 42, "get int field 42")
+    assert_int_eq(json_get_int(obj, "negative"), -7, "get negative int field")
+    assert_int_eq(json_get_int(obj, "zero"), 0, "get zero int field")
+    assert_int_eq(json_get_int(obj, "missing"), 0, "missing int field returns 0")
+    return ""
+}
+
+fn test_json_get_bool_basic(_: String) -> String {
+    let obj: String = "{\"ok\":true,\"fail\":false}"
+    assert_true(json_get_bool(obj, "ok"), "get true bool field")
+    assert_false(json_get_bool(obj, "fail"), "get false bool field")
+    assert_false(json_get_bool(obj, "missing"), "missing bool field returns false")
+    return ""
+}
+
+fn test_json_get_float_basic(_: String) -> String {
+    let obj: String = "{\"ratio\":3.14,\"negative\":-1.5}"
+    let ratio: Float = json_get_float(obj, "ratio")
+    assert_true(ratio > 3.13, "ratio > 3.13")
+    assert_true(ratio < 3.15, "ratio < 3.15")
+    let neg: Float = json_get_float(obj, "negative")
+    assert_true(neg < -1.4, "negative float")
+    assert_true(neg > -1.6, "negative float bound")
+    return ""
+}
+
+// ── json_set ──────────────────────────────────────────────────────────────────
+
+fn test_json_set_basic(_: String) -> String {
+    let obj: String = "{\"name\":\"alice\"}"
+    let obj2: String = json_set(obj, "name", "\"bob\"")
+    assert_eq(json_get(obj2, "name"), "bob", "overwrites existing key")
+
+    let obj3: String = json_set(obj, "role", "\"admin\"")
+    assert_eq(json_get(obj3, "role"), "admin", "inserts new key")
+    assert_eq(json_get(obj3, "name"), "alice", "existing key unchanged")
+    return ""
+}
+
+fn test_json_set_numeric(_: String) -> String {
+    let obj: String = "{}"
+    let obj2: String = json_set(obj, "count", "42")
+    assert_eq(json_get(obj2, "count"), "42", "set integer value")
+
+    let obj3: String = json_set(obj2, "count", "100")
+    assert_eq(json_get(obj3, "count"), "100", "overwrites integer value")
+    return ""
+}
+
+fn test_json_set_chained(_: String) -> String {
+    let obj: String = "{}"
+    let obj1: String = json_set(obj, "a", "\"1\"")
+    let obj2: String = json_set(obj1, "b", "\"2\"")
+    let obj3: String = json_set(obj2, "c", "\"3\"")
+    assert_eq(json_get(obj3, "a"), "1", "chained set: a")
+    assert_eq(json_get(obj3, "b"), "2", "chained set: b")
+    assert_eq(json_get(obj3, "c"), "3", "chained set: c")
+    return ""
+}
+
+// ── json_array_len ────────────────────────────────────────────────────────────
+
+fn test_json_array_len_basic(_: String) -> String {
+    assert_int_eq(json_array_len("[]"), 0, "empty array has length 0")
+    assert_int_eq(json_array_len("[1]"), 1, "single element array")
+    assert_int_eq(json_array_len("[1,2,3]"), 3, "three element array")
+    assert_int_eq(json_array_len("[\"a\",\"b\"]"), 2, "string array length")
+    assert_int_eq(json_array_len("[1,2,3,4,5]"), 5, "five element array")
+    return ""
+}
+
+// ── json_array_get / json_array_get_string ────────────────────────────────────
+
+fn test_json_array_get_basic(_: String) -> String {
+    let arr: String = "[\"alpha\",\"beta\",\"gamma\"]"
+    assert_eq(json_array_get_string(arr, 0), "alpha", "first element")
+    assert_eq(json_array_get_string(arr, 1), "beta", "second element")
+    assert_eq(json_array_get_string(arr, 2), "gamma", "third element")
+    assert_eq(json_array_get_string(arr, 3), "", "out of bounds returns empty")
+    return ""
+}
+
+fn test_json_array_get_numbers(_: String) -> String {
+    let arr: String = "[10,20,30]"
+    assert_eq(json_array_get(arr, 0), "10", "first number as fragment")
+    assert_eq(json_array_get(arr, 1), "20", "second number as fragment")
+    assert_eq(json_array_get(arr, 2), "30", "third number as fragment")
+    assert_int_eq(str_to_int(json_array_get(arr, 0)), 10, "convert fragment to int")
+    return ""
+}
+
+fn test_json_array_get_objects(_: String) -> String {
+    let arr: String = "[{\"name\":\"alice\"},{\"name\":\"bob\"}]"
+    let first: String = json_array_get(arr, 0)
+    let second: String = json_array_get(arr, 1)
+    assert_eq(json_get(first, "name"), "alice", "first object name")
+    assert_eq(json_get(second, "name"), "bob", "second object name")
+    assert_int_eq(json_array_len(arr), 2, "array of objects has correct length")
+    return ""
+}
+
+// ── json_escape_string ────────────────────────────────────────────────────────
+
+fn test_json_escape_string_basic(_: String) -> String {
+    assert_eq(json_escape_string("hello"), "hello", "plain string unchanged")
+    assert_eq(json_escape_string(""), "", "empty string unchanged")
+    assert_contains(json_escape_string("say \"hello\""), "\\\"", "double quotes escaped")
+    assert_contains(json_escape_string("line1\nline2"), "\\n", "newline escaped")
+    assert_contains(json_escape_string("col1\tcol2"), "\\t", "tab escaped")
+    return ""
+}
+
+fn test_json_escape_string_backslash(_: String) -> String {
+    let escaped: String = json_escape_string("a\\b")
+    assert_contains(escaped, "\\\\", "backslash doubled")
+    assert_true(str_len(escaped) > 3, "escaped is longer than original")
+    return ""
+}
+
+fn test_json_escape_roundtrip(_: String) -> String {
+    // Build a JSON string with an escaped value and extract it back
+    let raw: String = "hello world"
+    let escaped: String = json_escape_string(raw)
+    let json_str: String = "{\"msg\":\"" + escaped + "\"}"
+    assert_eq(json_get(json_str, "msg"), raw, "roundtrip: escape then parse")
+    return ""
+}
+
+// ── json_build_object ─────────────────────────────────────────────────────────
+
+fn test_json_build_object_basic(_: String) -> String {
+    let parts: [String] = el_list_empty()
+    let parts = el_list_append(parts, "name")
+    let parts = el_list_append(parts, "alice")
+    let parts = el_list_append(parts, "role")
+    let parts = el_list_append(parts, "admin")
+    let obj: String = json_build_object(parts)
+    assert_eq(json_get(obj, "name"), "alice", "build object: name field")
+    assert_eq(json_get(obj, "role"), "admin", "build object: role field")
+    assert_true(str_starts_with(obj, "{"), "build object starts with {")
+    assert_true(str_ends_with(obj, "}"), "build object ends with }")
+    return ""
+}
+
+fn test_json_build_object_empty(_: String) -> String {
+    let parts: [String] = el_list_empty()
+    let obj: String = json_build_object(parts)
+    assert_true(str_starts_with(obj, "{"), "empty build object starts with {")
+    assert_true(str_ends_with(obj, "}"), "empty build object ends with }")
+    return ""
+}
+
+// ── json_build_array ──────────────────────────────────────────────────────────
+
+fn test_json_build_array_basic(_: String) -> String {
+    let items: [String] = el_list_empty()
+    let items = el_list_append(items, "\"alice\"")
+    let items = el_list_append(items, "\"bob\"")
+    let arr: String = json_build_array(items)
+    assert_int_eq(json_array_len(arr), 2, "built array has 2 elements")
+    assert_eq(json_array_get_string(arr, 0), "alice", "first element of built array")
+    assert_eq(json_array_get_string(arr, 1), "bob", "second element of built array")
+    return ""
+}
+
+fn test_json_build_array_empty(_: String) -> String {
+    let items: [String] = el_list_empty()
+    let arr: String = json_build_array(items)
+    assert_int_eq(json_array_len(arr), 0, "empty built array has 0 elements")
+    assert_eq(arr, "[]", "empty array is []")
+    return ""
+}
+
+fn test_json_build_array_numbers(_: String) -> String {
+    let items: [String] = el_list_empty()
+    let items = el_list_append(items, "1")
+    let items = el_list_append(items, "2")
+    let items = el_list_append(items, "3")
+    let arr: String = json_build_array(items)
+    assert_int_eq(json_array_len(arr), 3, "numeric array has 3 elements")
+    assert_eq(json_array_get(arr, 0), "1", "first numeric element")
+    assert_eq(json_array_get(arr, 2), "3", "last numeric element")
+    return ""
+}
+
+// ── json_array_push ───────────────────────────────────────────────────────────
+
+fn test_json_array_push_basic(_: String) -> String {
+    let arr: String = "[]"
+    let arr2: String = json_array_push(arr, "\"hello\"")
+    assert_int_eq(json_array_len(arr2), 1, "after push: length 1")
+    assert_eq(json_array_get_string(arr2, 0), "hello", "pushed element accessible")
+
+    let arr3: String = json_array_push(arr2, "\"world\"")
+    assert_int_eq(json_array_len(arr3), 2, "after second push: length 2")
+    assert_eq(json_array_get_string(arr3, 1), "world", "second pushed element")
+    return ""
+}
+
+fn test_json_array_push_preserves_order(_: String) -> String {
+    let arr: String = "[\"a\",\"b\"]"
+    let arr2: String = json_array_push(arr, "\"c\"")
+    assert_eq(json_array_get_string(arr2, 0), "a", "first element preserved")
+    assert_eq(json_array_get_string(arr2, 1), "b", "second element preserved")
+    assert_eq(json_array_get_string(arr2, 2), "c", "pushed element at end")
+    assert_int_eq(json_array_len(arr2), 3, "total length after push")
+    return ""
+}
+
+// ── nested JSON ───────────────────────────────────────────────────────────────
+
+fn test_json_nested_set_get(_: String) -> String {
+    let obj: String = "{\"user\":{\"name\":\"alice\"},\"count\":1}"
+    assert_eq(json_get(obj, "user.name"), "alice", "deep get via dot path")
+    assert_eq(json_get(obj, "count"), "1", "top-level int field")
+
+    let obj2: String = json_set(obj, "count", "2")
+    assert_eq(json_get(obj2, "count"), "2", "updated top-level field")
+    assert_eq(json_get(obj2, "user.name"), "alice", "nested field still accessible after set")
+    return ""
+}
+
+fn test_json_array_of_objects(_: String) -> String {
+    let arr: String = "[{\"id\":1,\"name\":\"alice\"},{\"id\":2,\"name\":\"bob\"}]"
+    assert_int_eq(json_array_len(arr), 2, "array of objects: length 2")
+    let first: String = json_array_get(arr, 0)
+    let second: String = json_array_get(arr, 1)
+    assert_eq(json_get(first, "name"), "alice", "first object name")
+    assert_eq(json_get(second, "name"), "bob", "second object name")
+    assert_eq(json_get(first, "id"), "1", "first object id")
+    assert_eq(json_get(second, "id"), "2", "second object id")
+    return ""
+}

tests/suite/src/test_math.el

@@ -0,0 +1,229 @@
+// tests/suite/test_math.el — comprehensive tests for runtime/math.el
+//
+// Covers every public function in math.el: integer utilities, float math,
+// conversions, and rounding.  Import after runtime modules and test.el.
+
+// ── el_abs ────────────────────────────────────────────────────────────────────
+
+fn test_el_abs_basic(_: String) -> String {
+    assert_int_eq(el_abs(5), 5, "positive stays positive")
+    assert_int_eq(el_abs(-5), 5, "negative becomes positive")
+    assert_int_eq(el_abs(0), 0, "zero stays zero")
+    assert_int_eq(el_abs(-1), 1, "negative one becomes one")
+    assert_int_eq(el_abs(1000000), 1000000, "large positive unchanged")
+    assert_int_eq(el_abs(-1000000), 1000000, "large negative becomes positive")
+    return ""
+}
+
+// ── el_max ────────────────────────────────────────────────────────────────────
+
+fn test_el_max_basic(_: String) -> String {
+    assert_int_eq(el_max(3, 5), 5, "5 is larger than 3")
+    assert_int_eq(el_max(5, 3), 5, "5 is larger than 3 (reversed args)")
+    assert_int_eq(el_max(4, 4), 4, "equal values returns the value")
+    assert_int_eq(el_max(-1, -5), -1, "larger of two negatives")
+    assert_int_eq(el_max(0, -1), 0, "zero is larger than negative")
+    assert_int_eq(el_max(-1, 0), 0, "zero is larger than negative (reversed)")
+    return ""
+}
+
+fn test_el_max_edge(_: String) -> String {
+    assert_int_eq(el_max(0, 0), 0, "max of zeros is zero")
+    assert_int_eq(el_max(1000000, 999999), 1000000, "large values")
+    assert_int_eq(el_max(-1000000, 1000000), 1000000, "mixed sign large values")
+    assert_int_eq(el_max(1, 2), 2, "sequential integers")
+    return ""
+}
+
+// ── el_min ────────────────────────────────────────────────────────────────────
+
+fn test_el_min_basic(_: String) -> String {
+    assert_int_eq(el_min(3, 5), 3, "3 is smaller than 5")
+    assert_int_eq(el_min(5, 3), 3, "3 is smaller than 5 (reversed args)")
+    assert_int_eq(el_min(4, 4), 4, "equal values returns the value")
+    assert_int_eq(el_min(-1, -5), -5, "smaller of two negatives")
+    assert_int_eq(el_min(0, -1), -1, "negative is smaller than zero")
+    assert_int_eq(el_min(-1, 0), -1, "negative is smaller than zero (reversed)")
+    return ""
+}
+
+fn test_el_min_edge(_: String) -> String {
+    assert_int_eq(el_min(0, 0), 0, "min of zeros is zero")
+    assert_int_eq(el_min(1000000, 999999), 999999, "large values")
+    assert_int_eq(el_min(-1000000, 1000000), -1000000, "mixed sign large values")
+    assert_int_eq(el_min(1, 2), 1, "sequential integers")
+    return ""
+}
+
+// ── math_sqrt ─────────────────────────────────────────────────────────────────
+
+fn test_math_sqrt_basic(_: String) -> String {
+    let r: Float = math_sqrt(4.0)
+    assert_true(r > 1.99, "sqrt(4) > 1.99")
+    assert_true(r < 2.01, "sqrt(4) < 2.01")
+
+    let r9: Float = math_sqrt(9.0)
+    assert_true(r9 > 2.99, "sqrt(9) > 2.99")
+    assert_true(r9 < 3.01, "sqrt(9) < 3.01")
+
+    let r1: Float = math_sqrt(1.0)
+    assert_true(r1 > 0.99, "sqrt(1) is close to 1")
+    assert_true(r1 < 1.01, "sqrt(1) is close to 1")
+
+    let r0: Float = math_sqrt(0.0)
+    assert_true(r0 >= 0.0, "sqrt(0) is non-negative")
+    assert_true(r0 < 0.001, "sqrt(0) is close to 0")
+    return ""
+}
+
+fn test_math_sqrt_larger(_: String) -> String {
+    let r25: Float = math_sqrt(25.0)
+    assert_true(r25 > 4.99, "sqrt(25) > 4.99")
+    assert_true(r25 < 5.01, "sqrt(25) < 5.01")
+
+    let r100: Float = math_sqrt(100.0)
+    assert_true(r100 > 9.99, "sqrt(100) > 9.99")
+    assert_true(r100 < 10.01, "sqrt(100) < 10.01")
+
+    let r2: Float = math_sqrt(2.0)
+    assert_true(r2 > 1.41, "sqrt(2) > 1.41")
+    assert_true(r2 < 1.43, "sqrt(2) < 1.43")
+    return ""
+}
+
+// ── math_log / math_ln ───────────────────────────────────────────────────────
+
+fn test_math_log_basic(_: String) -> String {
+    let log10: Float = math_log(10.0)
+    assert_true(log10 > 0.99, "log(10) > 0.99")
+    assert_true(log10 < 1.01, "log(10) < 1.01")
+
+    let log1: Float = math_log(1.0)
+    assert_true(log1 > -0.001, "log(1) is close to 0")
+    assert_true(log1 < 0.001, "log(1) is close to 0")
+
+    let log100: Float = math_log(100.0)
+    assert_true(log100 > 1.99, "log(100) > 1.99")
+    assert_true(log100 < 2.01, "log(100) < 2.01")
+    return ""
+}
+
+fn test_math_ln_basic(_: String) -> String {
+    let lne: Float = math_ln(2.718281828)
+    assert_true(lne > 0.99, "ln(e) is close to 1")
+    assert_true(lne < 1.01, "ln(e) is close to 1")
+
+    let ln1: Float = math_ln(1.0)
+    assert_true(ln1 > -0.001, "ln(1) is close to 0")
+    assert_true(ln1 < 0.001, "ln(1) is close to 0")
+
+    let ln10: Float = math_ln(10.0)
+    assert_true(ln10 > 2.30, "ln(10) > 2.30")
+    assert_true(ln10 < 2.31, "ln(10) < 2.31")
+    return ""
+}
+
+// ── math_sin / math_cos / math_pi ────────────────────────────────────────────
+
+fn test_math_pi_basic(_: String) -> String {
+    let pi: Float = math_pi()
+    assert_true(pi > 3.14, "pi > 3.14")
+    assert_true(pi < 3.15, "pi < 3.15")
+    assert_true(pi > 0.0, "pi is positive")
+    assert_true(pi == math_pi(), "pi is constant across calls")
+    return ""
+}
+
+fn test_math_sin_basic(_: String) -> String {
+    let sin0: Float = math_sin(0.0)
+    assert_true(sin0 > -0.001, "sin(0) is close to 0")
+    assert_true(sin0 < 0.001, "sin(0) is close to 0")
+
+    let pi: Float = math_pi()
+    let sin_half_pi: Float = math_sin(pi / 2.0)
+    assert_true(sin_half_pi > 0.99, "sin(pi/2) is close to 1")
+    assert_true(sin_half_pi < 1.01, "sin(pi/2) is close to 1")
+    return ""
+}
+
+fn test_math_cos_basic(_: String) -> String {
+    let cos0: Float = math_cos(0.0)
+    assert_true(cos0 > 0.99, "cos(0) is close to 1")
+    assert_true(cos0 < 1.01, "cos(0) is close to 1")
+
+    let pi: Float = math_pi()
+    let cos_pi: Float = math_cos(pi)
+    assert_true(cos_pi < -0.99, "cos(pi) is close to -1")
+    assert_true(cos_pi > -1.01, "cos(pi) is close to -1")
+    return ""
+}
+
+// ── int_to_float / float_to_int ──────────────────────────────────────────────
+//
+// NOTE: int_to_float, float_to_int, format_float, and decimal_round use seed
+// primitives (__int_to_float, __float_to_int, __format_float) that are not yet
+// implemented in el_seed.c on the runtime/integrate branch. These tests are
+// omitted until those seed primitives are available. The float arithmetic and
+// comparison tests below exercise the float type via language builtins instead.
+
+// ── Integer arithmetic (language built-ins) ───────────────────────────────────
+
+fn test_int_arithmetic_basic(_: String) -> String {
+    assert_int_eq(2 + 3, 5, "addition")
+    assert_int_eq(10 - 4, 6, "subtraction")
+    assert_int_eq(3 * 4, 12, "multiplication")
+    assert_int_eq(10 / 3, 3, "integer division truncates")
+    assert_int_eq(10 % 3, 1, "modulo")
+    assert_int_eq(0 - 5, -5, "negation via subtraction")
+    return ""
+}
+
+fn test_int_arithmetic_edge(_: String) -> String {
+    assert_int_eq(0 + 0, 0, "zero plus zero")
+    assert_int_eq(0 * 100, 0, "zero times anything")
+    assert_int_eq(1 * 1, 1, "one times one")
+    assert_int_eq(100 / 100, 1, "divide by self")
+    assert_int_eq(7 % 7, 0, "self modulo is zero")
+    assert_int_eq(-5 + 5, 0, "additive inverse")
+    return ""
+}
+
+fn test_int_arithmetic_negative(_: String) -> String {
+    assert_int_eq(-3 + -2, -5, "negative addition")
+    assert_int_eq(-3 * 4, -12, "negative times positive")
+    assert_int_eq(-10 / 3, -3, "negative division truncates toward zero")
+    assert_int_eq(0 - 1000, -1000, "large negative")
+    assert_int_eq(-1 * -1, 1, "negative times negative is positive")
+    return ""
+}
+
+// ── Float arithmetic (language built-ins) ────────────────────────────────────
+
+fn test_float_arithmetic_basic(_: String) -> String {
+    let a: Float = 1.5 + 2.5
+    assert_true(a > 3.99, "1.5 + 2.5 = 4.0")
+    assert_true(a < 4.01, "1.5 + 2.5 = 4.0")
+
+    let b: Float = 5.0 - 2.5
+    assert_true(b > 2.49, "5.0 - 2.5 = 2.5")
+    assert_true(b < 2.51, "5.0 - 2.5 = 2.5")
+
+    let c: Float = 2.0 * 3.0
+    assert_true(c > 5.99, "2.0 * 3.0 = 6.0")
+    assert_true(c < 6.01, "2.0 * 3.0 = 6.0")
+
+    let d: Float = 9.0 / 3.0
+    assert_true(d > 2.99, "9.0 / 3.0 = 3.0")
+    assert_true(d < 3.01, "9.0 / 3.0 = 3.0")
+    return ""
+}
+
+fn test_float_comparison_basic(_: String) -> String {
+    assert_true(1.0 < 2.0, "1.0 < 2.0")
+    assert_true(2.0 > 1.0, "2.0 > 1.0")
+    assert_false(1.0 > 2.0, "1.0 not > 2.0")
+    assert_false(2.0 < 1.0, "2.0 not < 1.0")
+    assert_true(1.5 >= 1.5, "1.5 >= 1.5")
+    assert_true(1.5 <= 1.5, "1.5 <= 1.5")
+    return ""
+}

tests/suite/src/test_state.el

@@ -0,0 +1,168 @@
+// tests/suite/test_state.el — comprehensive tests for runtime/state.el
+//
+// Covers state_set, state_get, state_del, state_keys, state_has, state_get_or.
+// Uses unique key prefixes to avoid interference with the test framework's
+// own state keys (which use _test_ prefix).
+
+// ── state_set / state_get roundtrip ───────────────────────────────────────────
+
+fn test_state_set_get_basic(_: String) -> String {
+    state_set("suite_key1", "hello")
+    assert_eq(state_get("suite_key1"), "hello", "get back what was set")
+
+    state_set("suite_key2", "world")
+    assert_eq(state_get("suite_key2"), "world", "second key independent")
+
+    state_set("suite_num", "42")
+    assert_eq(state_get("suite_num"), "42", "numeric string value")
+
+    state_set("suite_empty", "")
+    // empty value and missing key both return "" — that's by design per the docs
+    let v: String = state_get("suite_empty")
+    assert_true(str_eq(v, "") || str_eq(v, ""), "empty value stored or treated as absent")
+
+    state_set("suite_long", str_repeat("a", 100))
+    assert_int_eq(str_len(state_get("suite_long")), 100, "long value preserved")
+    return ""
+}
+
+fn test_state_overwrite(_: String) -> String {
+    state_set("suite_over", "first")
+    assert_eq(state_get("suite_over"), "first", "initial value")
+    state_set("suite_over", "second")
+    assert_eq(state_get("suite_over"), "second", "value overwritten")
+    state_set("suite_over", "third")
+    assert_eq(state_get("suite_over"), "third", "value overwritten again")
+    return ""
+}
+
+fn test_state_multiple_keys(_: String) -> String {
+    state_set("suite_mk_a", "alpha")
+    state_set("suite_mk_b", "beta")
+    state_set("suite_mk_c", "gamma")
+    assert_eq(state_get("suite_mk_a"), "alpha", "key a is alpha")
+    assert_eq(state_get("suite_mk_b"), "beta", "key b is beta")
+    assert_eq(state_get("suite_mk_c"), "gamma", "key c is gamma")
+    // Mutate one, others unchanged
+    state_set("suite_mk_b", "BETA")
+    assert_eq(state_get("suite_mk_a"), "alpha", "a unchanged after b mutated")
+    assert_eq(state_get("suite_mk_b"), "BETA", "b updated")
+    assert_eq(state_get("suite_mk_c"), "gamma", "c unchanged after b mutated")
+    return ""
+}
+
+// ── missing keys ──────────────────────────────────────────────────────────────
+
+fn test_state_missing_key(_: String) -> String {
+    assert_eq(state_get("suite_definitely_not_set_xyz_123"), "", "missing key returns empty string")
+    assert_eq(state_get("suite_another_missing_key_abc"), "", "another missing key returns empty string")
+    return ""
+}
+
+// ── state_del ─────────────────────────────────────────────────────────────────
+
+fn test_state_del_basic(_: String) -> String {
+    state_set("suite_del1", "value_to_delete")
+    assert_eq(state_get("suite_del1"), "value_to_delete", "key present before delete")
+    state_del("suite_del1")
+    assert_eq(state_get("suite_del1"), "", "key absent after delete")
+
+    // Delete a non-existent key should not error
+    state_del("suite_never_existed_key_xyz")
+    assert_eq(state_get("suite_never_existed_key_xyz"), "", "delete non-existent is no-op")
+    return ""
+}
+
+fn test_state_del_and_reset(_: String) -> String {
+    state_set("suite_reuse", "original")
+    assert_eq(state_get("suite_reuse"), "original", "original value")
+    state_del("suite_reuse")
+    assert_eq(state_get("suite_reuse"), "", "deleted")
+    state_set("suite_reuse", "new_value")
+    assert_eq(state_get("suite_reuse"), "new_value", "key reused after delete")
+    return ""
+}
+
+// ── state_has ─────────────────────────────────────────────────────────────────
+
+fn test_state_has_basic(_: String) -> String {
+    state_set("suite_has1", "something")
+    assert_true(state_has("suite_has1"), "key with value is present")
+    assert_false(state_has("suite_definitely_absent_xyz_999"), "absent key returns false")
+
+    state_del("suite_has1")
+    assert_false(state_has("suite_has1"), "deleted key is not present")
+    return ""
+}
+
+// ── state_get_or ──────────────────────────────────────────────────────────────
+
+fn test_state_get_or_basic(_: String) -> String {
+    state_set("suite_gor1", "present")
+    assert_eq(state_get_or("suite_gor1", "default"), "present", "returns value when key exists")
+    assert_eq(state_get_or("suite_gor_missing_xyz", "fallback"), "fallback", "returns default when key missing")
+    assert_eq(state_get_or("suite_gor_missing_xyz", ""), "", "returns empty default when key missing")
+    return ""
+}
+
+// ── state persists across function calls ──────────────────────────────────────
+
+fn _suite_state_helper_write() {
+    state_set("suite_persist_test", "written_by_helper")
+}
+
+fn _suite_state_helper_increment() {
+    let n: Int = str_to_int(state_get("suite_counter"))
+    state_set("suite_counter", int_to_str(n + 1))
+}
+
+fn test_state_cross_function(_: String) -> String {
+    _suite_state_helper_write()
+    assert_eq(state_get("suite_persist_test"), "written_by_helper", "value written by helper function is readable")
+
+    state_set("suite_counter", "0")
+    _suite_state_helper_increment()
+    assert_eq(state_get("suite_counter"), "1", "counter after 1 increment")
+    _suite_state_helper_increment()
+    assert_eq(state_get("suite_counter"), "2", "counter after 2 increments")
+    _suite_state_helper_increment()
+    assert_eq(state_get("suite_counter"), "3", "counter after 3 increments")
+    return ""
+}
+
+// ── state_keys ────────────────────────────────────────────────────────────────
+
+fn test_state_keys_basic(_: String) -> String {
+    state_set("suite_sk_x", "1")
+    state_set("suite_sk_y", "2")
+    let keys: String = state_keys()
+    // keys is a JSON array of all state keys — must contain our test keys
+    assert_true(str_contains(keys, "suite_sk_x"), "keys includes suite_sk_x")
+    assert_true(str_contains(keys, "suite_sk_y"), "keys includes suite_sk_y")
+    assert_true(str_starts_with(keys, "["), "keys is a JSON array")
+    assert_true(str_ends_with(keys, "]"), "keys is a JSON array")
+    assert_true(json_array_len(keys) > 0, "keys array is non-empty")
+    return ""
+}
+
+// ── value type storage ────────────────────────────────────────────────────────
+
+fn test_state_value_types(_: String) -> String {
+    // JSON object as value
+    let json_val: String = "{\"name\":\"alice\",\"age\":30}"
+    state_set("suite_json_val", json_val)
+    let retrieved: String = state_get("suite_json_val")
+    assert_eq(json_get(retrieved, "name"), "alice", "JSON object stored and retrieved")
+
+    // JSON array as value
+    let arr_val: String = "[1,2,3]"
+    state_set("suite_arr_val", arr_val)
+    let retrieved_arr: String = state_get("suite_arr_val")
+    assert_int_eq(json_array_len(retrieved_arr), 3, "JSON array stored and retrieved")
+
+    // Large value
+    let big: String = str_repeat("x", 500)
+    state_set("suite_big_val", big)
+    assert_int_eq(str_len(state_get("suite_big_val")), 500, "large value stored correctly")
+    return ""
+}

tests/suite/src/test_string.el

@@ -0,0 +1,575 @@
+// tests/suite/test_string.el — comprehensive tests for runtime/string.el
+//
+// Covers every public function in string.el.  Import this file after all
+// runtime modules and runtime/test.el have been concatenated in.
+
+// ── str_eq ────────────────────────────────────────────────────────────────────
+
+fn test_str_eq_basic(_: String) -> String {
+    assert_true(str_eq("hello", "hello"), "identical strings are equal")
+    assert_false(str_eq("hello", "world"), "different strings are not equal")
+    assert_true(str_eq("", ""), "empty strings are equal")
+    assert_false(str_eq("a", ""), "non-empty vs empty is not equal")
+    assert_false(str_eq("", "a"), "empty vs non-empty is not equal")
+    assert_false(str_eq("Hello", "hello"), "comparison is case-sensitive")
+    return ""
+}
+
+fn test_str_eq_symbols(_: String) -> String {
+    assert_true(str_eq("!@#$", "!@#$"), "symbols are equal")
+    assert_true(str_eq("  ", "  "), "spaces match")
+    assert_false(str_eq(" a", "a "), "leading vs trailing space differ")
+    assert_false(str_eq("abc", "ab"), "prefix not equal to full string")
+    assert_false(str_eq("ab", "abc"), "shorter not equal to longer")
+    return ""
+}
+
+// ── str_len ───────────────────────────────────────────────────────────────────
+
+fn test_str_len_basic(_: String) -> String {
+    assert_int_eq(str_len(""), 0, "empty string has length 0")
+    assert_int_eq(str_len("a"), 1, "single char has length 1")
+    assert_int_eq(str_len("hello"), 5, "hello has length 5")
+    assert_int_eq(str_len("hello world"), 11, "space counted in length")
+    assert_int_eq(str_len("12345"), 5, "digits counted correctly")
+    assert_int_eq(str_len("!@#$%"), 5, "punctuation counted correctly")
+    return ""
+}
+
+fn test_str_len_longer(_: String) -> String {
+    let s: String = str_repeat("ab", 50)
+    assert_int_eq(str_len(s), 100, "repeated string has correct length")
+    assert_int_eq(str_len("abcdefghij"), 10, "10-char string")
+    return ""
+}
+
+// ── str_concat / + operator ───────────────────────────────────────────────────
+
+fn test_str_concat_basic(_: String) -> String {
+    assert_eq(str_concat("hello", " world"), "hello world", "basic concat")
+    assert_eq(str_concat("", "world"), "world", "empty prefix")
+    assert_eq(str_concat("hello", ""), "hello", "empty suffix")
+    assert_eq(str_concat("", ""), "", "both empty")
+    assert_eq("foo" + "bar", "foobar", "operator + concat")
+    return ""
+}
+
+fn test_str_concat_chaining(_: String) -> String {
+    let a: String = "hello"
+    let b: String = " "
+    let c: String = "world"
+    assert_eq(a + b + c, "hello world", "chained concat")
+    assert_eq(str_concat(str_concat("a", "b"), "c"), "abc", "nested concat")
+    assert_int_eq(str_len(str_concat("abc", "def")), 6, "length after concat")
+    return ""
+}
+
+// ── str_slice ─────────────────────────────────────────────────────────────────
+
+fn test_str_slice_basic(_: String) -> String {
+    assert_eq(str_slice("hello world", 0, 5), "hello", "slice from start")
+    assert_eq(str_slice("hello world", 6, 11), "world", "slice from middle")
+    assert_eq(str_slice("hello world", 0, 0), "", "zero-length slice")
+    assert_eq(str_slice("hello", 0, 100), "hello", "end clamped to length")
+    assert_eq(str_slice("hello", 3, 3), "", "start == end is empty")
+    assert_eq(str_slice("hello world", 2, 7), "llo w", "interior slice")
+    return ""
+}
+
+fn test_str_slice_edge(_: String) -> String {
+    assert_eq(str_slice("", 0, 0), "", "empty string slice")
+    assert_eq(str_slice("abc", 1, 2), "b", "single char slice")
+    assert_eq(str_slice("abc", 0, 3), "abc", "full string slice")
+    assert_eq(str_slice("abc", 2, 1), "", "inverted range is empty")
+    assert_eq(str_slice("hello", 5, 5), "", "slice at end is empty")
+    return ""
+}
+
+// ── str_starts_with ───────────────────────────────────────────────────────────
+
+fn test_str_starts_with_basic(_: String) -> String {
+    assert_true(str_starts_with("hello world", "hello"), "prefix present")
+    assert_false(str_starts_with("hello world", "world"), "not a prefix")
+    assert_true(str_starts_with("hello", "hello"), "string is its own prefix")
+    assert_true(str_starts_with("hello", ""), "empty prefix always true")
+    assert_false(str_starts_with("", "a"), "empty string has no non-empty prefix")
+    assert_false(str_starts_with("hi", "hello"), "prefix longer than string")
+    return ""
+}
+
+fn test_str_starts_with_edge(_: String) -> String {
+    assert_true(str_starts_with("abc", "a"), "single-char prefix")
+    assert_false(str_starts_with("abc", "b"), "wrong single-char prefix")
+    assert_true(str_starts_with("", ""), "empty starts with empty")
+    assert_true(str_starts_with("hello world", "hello world"), "full string is prefix")
+    assert_false(str_starts_with("hello", "HELLO"), "case-sensitive prefix")
+    return ""
+}
+
+// ── str_ends_with ─────────────────────────────────────────────────────────────
+
+fn test_str_ends_with_basic(_: String) -> String {
+    assert_true(str_ends_with("hello world", "world"), "suffix present")
+    assert_false(str_ends_with("hello world", "hello"), "not a suffix")
+    assert_true(str_ends_with("hello", "hello"), "string is its own suffix")
+    assert_true(str_ends_with("hello", ""), "empty suffix always true")
+    assert_false(str_ends_with("", "a"), "empty string has no non-empty suffix")
+    assert_false(str_ends_with("hi", "world"), "suffix longer than string")
+    return ""
+}
+
+fn test_str_ends_with_edge(_: String) -> String {
+    assert_true(str_ends_with("abc", "c"), "single-char suffix")
+    assert_false(str_ends_with("abc", "b"), "wrong single-char suffix")
+    assert_true(str_ends_with("", ""), "empty ends with empty")
+    assert_false(str_ends_with("hello", "HELLO"), "case-sensitive suffix")
+    assert_true(str_ends_with("file.txt", ".txt"), "common file extension case")
+    return ""
+}
+
+// ── str_contains ─────────────────────────────────────────────────────────────
+
+fn test_str_contains_basic(_: String) -> String {
+    assert_true(str_contains("hello world", "world"), "contains at end")
+    assert_true(str_contains("hello world", "hello"), "contains at start")
+    assert_true(str_contains("hello world", "lo wo"), "contains in middle")
+    assert_false(str_contains("hello world", "xyz"), "not contained")
+    assert_true(str_contains("hello", ""), "empty sub always contained")
+    assert_false(str_contains("", "a"), "empty string contains nothing")
+    return ""
+}
+
+fn test_str_contains_edge(_: String) -> String {
+    assert_true(str_contains("hello", "hello"), "string contains itself")
+    assert_false(str_contains("hello", "helloo"), "longer sub not contained")
+    assert_true(str_contains("aaa", "a"), "single char in repeated chars")
+    assert_true(str_contains("aaa", "aa"), "two-char sub in repeated chars")
+    assert_false(str_contains("abc", "ABC"), "case-sensitive")
+    return ""
+}
+
+// ── str_index_of ─────────────────────────────────────────────────────────────
+
+fn test_str_index_of_basic(_: String) -> String {
+    assert_int_eq(str_index_of("hello world", "world"), 6, "index of suffix")
+    assert_int_eq(str_index_of("hello world", "hello"), 0, "index of prefix")
+    assert_int_eq(str_index_of("hello world", "o"), 4, "index of first occurrence")
+    assert_int_eq(str_index_of("hello world", "xyz"), -1, "not found returns -1")
+    assert_int_eq(str_index_of("hello", ""), 0, "empty sub returns 0")
+    assert_int_eq(str_index_of("", "a"), -1, "search in empty string")
+    return ""
+}
+
+fn test_str_index_of_duplicates(_: String) -> String {
+    assert_int_eq(str_index_of("aababc", "ab"), 1, "finds first of two occurrences")
+    assert_int_eq(str_index_of("abab", "ab"), 0, "finds first at position 0")
+    assert_int_eq(str_index_of("xabab", "ab"), 1, "finds first after leading char")
+    assert_int_eq(str_index_of("hello hello", "hello"), 0, "finds first hello")
+    assert_int_eq(str_index_of("hello", "hello"), 0, "exact match at 0")
+    return ""
+}
+
+// ── str_last_index_of ─────────────────────────────────────────────────────────
+
+fn test_str_last_index_of_basic(_: String) -> String {
+    assert_int_eq(str_last_index_of("hello hello", "hello"), 6, "last occurrence index")
+    assert_int_eq(str_last_index_of("hello", "hello"), 0, "only one occurrence")
+    assert_int_eq(str_last_index_of("hello", "xyz"), -1, "not found returns -1")
+    assert_int_eq(str_last_index_of("aababc", "ab"), 3, "last ab in aababc")
+    assert_int_eq(str_last_index_of("abcabc", "abc"), 3, "last abc")
+    return ""
+}
+
+// ── str_replace ───────────────────────────────────────────────────────────────
+
+fn test_str_replace_basic(_: String) -> String {
+    assert_eq(str_replace("hello world", "world", "there"), "hello there", "basic replace")
+    assert_eq(str_replace("aaa", "a", "b"), "bbb", "replaces all occurrences")
+    assert_eq(str_replace("hello", "xyz", "abc"), "hello", "no match is identity")
+    assert_eq(str_replace("", "a", "b"), "", "empty string unchanged")
+    assert_eq(str_replace("hello", "", "x"), "hello", "empty from is identity")
+    return ""
+}
+
+fn test_str_replace_multiple(_: String) -> String {
+    assert_eq(str_replace("hello hello", "hello", "bye"), "bye bye", "replace multiple")
+    assert_eq(str_replace("aXbXc", "X", "-"), "a-b-c", "single-char delimiter")
+    assert_eq(str_replace("abcabc", "abc", "X"), "XX", "multi-char replaced twice")
+    assert_eq(str_replace("aabbcc", "bb", ""), "aacc", "replace with empty")
+    assert_eq(str_replace("hello", "hello", "world"), "world", "replace whole string")
+    return ""
+}
+
+// ── str_to_upper / str_to_lower ──────────────────────────────────────────────
+
+fn test_str_to_upper_basic(_: String) -> String {
+    assert_eq(str_to_upper("hello"), "HELLO", "lowercase to uppercase")
+    assert_eq(str_to_upper("HELLO"), "HELLO", "already uppercase unchanged")
+    assert_eq(str_to_upper("Hello World"), "HELLO WORLD", "mixed case")
+    assert_eq(str_to_upper(""), "", "empty string unchanged")
+    assert_eq(str_to_upper("hello123"), "HELLO123", "digits unchanged")
+    assert_eq(str_to_upper("abc-def"), "ABC-DEF", "punctuation unchanged")
+    return ""
+}
+
+fn test_str_to_lower_basic(_: String) -> String {
+    assert_eq(str_to_lower("HELLO"), "hello", "uppercase to lowercase")
+    assert_eq(str_to_lower("hello"), "hello", "already lowercase unchanged")
+    assert_eq(str_to_lower("Hello World"), "hello world", "mixed case")
+    assert_eq(str_to_lower(""), "", "empty string unchanged")
+    assert_eq(str_to_lower("HELLO123"), "hello123", "digits unchanged")
+    assert_eq(str_to_lower("ABC-DEF"), "abc-def", "punctuation unchanged")
+    return ""
+}
+
+fn test_str_upper_lower_roundtrip(_: String) -> String {
+    let s: String = "Hello, World!"
+    assert_eq(str_to_lower(str_to_upper(s)), "hello, world!", "upper then lower")
+    assert_eq(str_to_upper(str_to_lower(s)), "HELLO, WORLD!", "lower then upper")
+    assert_eq(str_to_upper(str_to_lower("ABC")), "ABC", "ABC roundtrip")
+    return ""
+}
+
+// ── str_trim / str_lstrip / str_rstrip ───────────────────────────────────────
+
+fn test_str_trim_basic(_: String) -> String {
+    assert_eq(str_trim("  hello  "), "hello", "trims spaces both sides")
+    assert_eq(str_trim("hello"), "hello", "no whitespace unchanged")
+    assert_eq(str_trim("   "), "", "all-space string becomes empty")
+    assert_eq(str_trim(""), "", "empty string unchanged")
+    assert_eq(str_trim("\t hello \n"), "hello", "trims tabs and newlines")
+    assert_eq(str_trim("  hello world  "), "hello world", "internal spaces preserved")
+    return ""
+}
+
+fn test_str_lstrip_rstrip(_: String) -> String {
+    assert_eq(str_lstrip("  hello  "), "hello  ", "lstrip removes leading spaces")
+    assert_eq(str_rstrip("  hello  "), "  hello", "rstrip removes trailing spaces")
+    assert_eq(str_lstrip("hello"), "hello", "lstrip no-op on clean string")
+    assert_eq(str_rstrip("hello"), "hello", "rstrip no-op on clean string")
+    assert_eq(str_lstrip(""), "", "lstrip empty string")
+    assert_eq(str_rstrip(""), "", "rstrip empty string")
+    return ""
+}
+
+// ── str_split ─────────────────────────────────────────────────────────────────
+
+fn test_str_split_basic(_: String) -> String {
+    let parts: [String] = str_split("a,b,c", ",")
+    assert_int_eq(el_list_len(parts), 3, "split yields 3 parts")
+    assert_eq(el_list_get(parts, 0), "a", "first part is a")
+    assert_eq(el_list_get(parts, 1), "b", "second part is b")
+    assert_eq(el_list_get(parts, 2), "c", "third part is c")
+    return ""
+}
+
+fn test_str_split_edge(_: String) -> String {
+    let single: [String] = str_split("hello", ",")
+    assert_int_eq(el_list_len(single), 1, "no sep found yields 1 part")
+    assert_eq(el_list_get(single, 0), "hello", "single part is the full string")
+
+    let trailing: [String] = str_split("a,b,", ",")
+    assert_int_eq(el_list_len(trailing), 3, "trailing sep yields empty last element")
+    assert_eq(el_list_get(trailing, 2), "", "last element is empty")
+
+    let multi: [String] = str_split("one::two::three", "::")
+    assert_int_eq(el_list_len(multi), 3, "multi-char separator works")
+    assert_eq(el_list_get(multi, 1), "two", "middle element correct")
+    return ""
+}
+
+// ── str_join ─────────────────────────────────────────────────────────────────
+
+fn test_str_join_basic(_: String) -> String {
+    let parts: [String] = el_list_empty()
+    let parts = el_list_append(parts, "a")
+    let parts = el_list_append(parts, "b")
+    let parts = el_list_append(parts, "c")
+    assert_eq(str_join(parts, ","), "a,b,c", "basic join with comma")
+    assert_eq(str_join(parts, ""), "abc", "join with empty separator")
+    assert_eq(str_join(parts, " | "), "a | b | c", "join with multi-char sep")
+    return ""
+}
+
+fn test_str_join_edge(_: String) -> String {
+    let empty_list: [String] = el_list_empty()
+    assert_eq(str_join(empty_list, ","), "", "joining empty list yields empty")
+
+    let one: [String] = el_list_empty()
+    let one = el_list_append(one, "solo")
+    assert_eq(str_join(one, ","), "solo", "joining single element yields that element")
+    assert_eq(str_join(one, "---"), "solo", "single element: no sep inserted")
+
+    let two: [String] = el_list_empty()
+    let two = el_list_append(two, "alpha")
+    let two = el_list_append(two, "beta")
+    assert_eq(str_join(two, ", "), "alpha, beta", "two elements join correctly")
+    return ""
+}
+
+// ── int_to_str / str_to_int ──────────────────────────────────────────────────
+
+fn test_int_to_str_basic(_: String) -> String {
+    assert_eq(int_to_str(0), "0", "zero")
+    assert_eq(int_to_str(42), "42", "positive integer")
+    assert_eq(int_to_str(-1), "-1", "negative integer")
+    assert_eq(int_to_str(1000000), "1000000", "large integer")
+    assert_eq(int_to_str(-999), "-999", "negative large")
+    assert_int_eq(str_len(int_to_str(12345)), 5, "correct digit count")
+    return ""
+}
+
+fn test_str_to_int_basic(_: String) -> String {
+    assert_int_eq(str_to_int("0"), 0, "zero")
+    assert_int_eq(str_to_int("42"), 42, "positive integer")
+    assert_int_eq(str_to_int("-1"), -1, "negative integer")
+    assert_int_eq(str_to_int("1000000"), 1000000, "large integer")
+    assert_int_eq(str_to_int("-999"), -999, "negative large")
+    assert_int_eq(str_to_int(int_to_str(12345)), 12345, "roundtrip")
+    return ""
+}
+
+// ── float_to_str / str_to_float ──────────────────────────────────────────────
+
+fn test_float_to_str_basic(_: String) -> String {
+    assert_eq(float_to_str(0.0), "0", "zero float to str")
+    assert_eq(float_to_str(1.5), "1.5", "basic float")
+    assert_eq(float_to_str(-3.14), "-3.14", "negative float")
+    assert_true(str_len(float_to_str(1.0)) > 0, "float_to_str produces output")
+    assert_contains(float_to_str(100.0), "100", "100.0 contains 100")
+    return ""
+}
+
+fn test_str_to_float_basic(_: String) -> String {
+    let f: Float = str_to_float("1.5")
+    let s: String = float_to_str(f)
+    assert_eq(s, "1.5", "roundtrip 1.5")
+
+    let f2: Float = str_to_float("0.0")
+    let s2: String = float_to_str(f2)
+    assert_eq(s2, "0", "roundtrip 0.0")
+
+    assert_true(str_to_float("3.14") > 3.13, "3.14 > 3.13")
+    assert_true(str_to_float("3.14") < 3.15, "3.14 < 3.15")
+    assert_true(str_to_float("-1.0") < 0.0, "negative float is negative")
+    return ""
+}
+
+// ── str_repeat / str_reverse ─────────────────────────────────────────────────
+
+fn test_str_repeat_basic(_: String) -> String {
+    assert_eq(str_repeat("ab", 3), "ababab", "repeat 3 times")
+    assert_eq(str_repeat("x", 1), "x", "repeat once")
+    assert_eq(str_repeat("x", 0), "", "repeat zero times yields empty")
+    assert_eq(str_repeat("", 5), "", "repeating empty string yields empty")
+    assert_eq(str_repeat("-", 4), "----", "single char repeat")
+    assert_int_eq(str_len(str_repeat("abc", 10)), 30, "length is n * len")
+    return ""
+}
+
+fn test_str_reverse_basic(_: String) -> String {
+    assert_eq(str_reverse("hello"), "olleh", "basic reverse")
+    assert_eq(str_reverse("a"), "a", "single char is its own reverse")
+    assert_eq(str_reverse(""), "", "empty string reverses to empty")
+    assert_eq(str_reverse("abcd"), "dcba", "even-length reverse")
+    assert_eq(str_reverse("racecar"), "racecar", "palindrome unchanged")
+    assert_eq(str_reverse("abc"), "cba", "three-char reverse")
+    return ""
+}
+
+// ── str_count ─────────────────────────────────────────────────────────────────
+
+fn test_str_count_basic(_: String) -> String {
+    assert_int_eq(str_count("hello world hello", "hello"), 2, "two occurrences")
+    assert_int_eq(str_count("aaa", "a"), 3, "adjacent single chars")
+    assert_int_eq(str_count("aaa", "aa"), 1, "non-overlapping: one match")
+    assert_int_eq(str_count("hello", "xyz"), 0, "no match")
+    assert_int_eq(str_count("", "a"), 0, "empty string has no occurrences")
+    assert_int_eq(str_count("hello", ""), 0, "empty sub returns 0")
+    return ""
+}
+
+// ── str_strip_prefix / str_strip_suffix ──────────────────────────────────────
+
+fn test_str_strip_prefix_basic(_: String) -> String {
+    assert_eq(str_strip_prefix("foobar", "foo"), "bar", "strips matching prefix")
+    assert_eq(str_strip_prefix("foobar", "baz"), "foobar", "no-match is identity")
+    assert_eq(str_strip_prefix("hello", ""), "hello", "empty prefix is identity")
+    assert_eq(str_strip_prefix("hello", "hello"), "", "full match yields empty")
+    assert_eq(str_strip_prefix("hello", "HELLO"), "hello", "case-sensitive no-match")
+    return ""
+}
+
+fn test_str_strip_suffix_basic(_: String) -> String {
+    assert_eq(str_strip_suffix("hello.md", ".md"), "hello", "strips matching suffix")
+    assert_eq(str_strip_suffix("hello.md", ".txt"), "hello.md", "no-match is identity")
+    assert_eq(str_strip_suffix("hello", ""), "hello", "empty suffix is identity")
+    assert_eq(str_strip_suffix("hello", "hello"), "", "full match yields empty")
+    assert_eq(str_strip_suffix("hello", "HELLO"), "hello", "case-sensitive no-match")
+    return ""
+}
+
+// ── str_find_chars ────────────────────────────────────────────────────────────
+
+fn test_str_find_chars_basic(_: String) -> String {
+    assert_int_eq(str_find_chars("hello world", " "), 5, "finds space at index 5")
+    assert_int_eq(str_find_chars("hello", "xyz"), -1, "not found returns -1")
+    assert_int_eq(str_find_chars("hello", ""), -1, "empty charset returns -1")
+    assert_int_eq(str_find_chars("hello", "aeiou"), 1, "finds first vowel at index 1")
+    assert_int_eq(str_find_chars("", "a"), -1, "search in empty string returns -1")
+    assert_int_eq(str_find_chars("abc", "c"), 2, "finds last char of string")
+    return ""
+}
+
+// ── str_char_at / str_char_code ───────────────────────────────────────────────
+
+fn test_str_char_at_basic(_: String) -> String {
+    assert_eq(str_char_at("hello", 0), "h", "first char")
+    assert_eq(str_char_at("hello", 4), "o", "last char")
+    assert_eq(str_char_at("hello", 2), "l", "middle char")
+    assert_eq(str_char_at("hello", -1), "", "negative index yields empty")
+    assert_eq(str_char_at("hello", 5), "", "out-of-bounds yields empty")
+    assert_eq(str_char_at("", 0), "", "empty string yields empty")
+    return ""
+}
+
+fn test_str_char_code_basic(_: String) -> String {
+    assert_int_eq(str_char_code("A", 0), 65, "A has code 65")
+    assert_int_eq(str_char_code("a", 0), 97, "a has code 97")
+    assert_int_eq(str_char_code("0", 0), 48, "0 has code 48")
+    assert_int_eq(str_char_code("hello", 0), 104, "h has code 104")
+    assert_int_eq(str_char_code("", 0), 0, "empty string yields 0")
+    assert_int_eq(str_char_code("a", 5), 0, "out-of-bounds yields 0")
+    return ""
+}
+
+// ── str_pad_left / str_pad_right ─────────────────────────────────────────────
+
+fn test_str_pad_left_basic(_: String) -> String {
+    assert_eq(str_pad_left("hi", 5, " "), "   hi", "pads to width 5")
+    assert_eq(str_pad_left("hi", 2, " "), "hi", "already at width is unchanged")
+    assert_eq(str_pad_left("hi", 1, " "), "hi", "wider than width is unchanged")
+    assert_eq(str_pad_left("5", 3, "0"), "005", "zero-pad a number")
+    assert_int_eq(str_len(str_pad_left("ab", 7, "x")), 7, "padded to exact width")
+    return ""
+}
+
+fn test_str_pad_right_basic(_: String) -> String {
+    assert_eq(str_pad_right("hi", 5, " "), "hi   ", "pads to width 5")
+    assert_eq(str_pad_right("hi", 2, " "), "hi", "already at width is unchanged")
+    assert_eq(str_pad_right("hi", 1, " "), "hi", "wider than width is unchanged")
+    assert_int_eq(str_len(str_pad_right("ab", 7, "-")), 7, "padded to exact width")
+    assert_starts_with(str_pad_right("ab", 7, "-"), "ab", "original string at start")
+    return ""
+}
+
+// ── Character classification ──────────────────────────────────────────────────
+
+fn test_is_letter_basic(_: String) -> String {
+    assert_true(is_letter("a"), "a is a letter")
+    assert_true(is_letter("Z"), "Z is a letter")
+    assert_true(is_letter("abc"), "abc all letters")
+    assert_false(is_letter("1"), "1 is not a letter")
+    assert_false(is_letter(""), "empty string is not a letter")
+    assert_false(is_letter("a1"), "a1 has non-letter")
+    return ""
+}
+
+fn test_is_digit_basic(_: String) -> String {
+    assert_true(is_digit("0"), "0 is a digit")
+    assert_true(is_digit("9"), "9 is a digit")
+    assert_true(is_digit("123"), "123 all digits")
+    assert_false(is_digit("a"), "a is not a digit")
+    assert_false(is_digit(""), "empty is not a digit")
+    assert_false(is_digit("1a"), "1a has non-digit")
+    return ""
+}
+
+fn test_is_whitespace_basic(_: String) -> String {
+    assert_true(is_whitespace(" "), "space is whitespace")
+    assert_true(is_whitespace("   "), "multiple spaces")
+    assert_false(is_whitespace("a"), "a is not whitespace")
+    assert_false(is_whitespace(""), "empty string is not whitespace")
+    assert_false(is_whitespace(" a"), "mixed is not all whitespace")
+    return ""
+}
+
+// ── str_count_lines / str_count_words ────────────────────────────────────────
+
+fn test_str_count_lines_basic(_: String) -> String {
+    assert_int_eq(str_count_lines(""), 0, "empty string has 0 lines")
+    assert_int_eq(str_count_lines("hello"), 1, "single line no newline")
+    assert_int_eq(str_count_lines("a\nb"), 2, "two lines with newline")
+    assert_int_eq(str_count_lines("a\nb\nc"), 3, "three lines")
+    assert_int_eq(str_count_lines("a\n"), 1, "trailing newline not counted as extra line")
+    return ""
+}
+
+fn test_str_count_words_basic(_: String) -> String {
+    assert_int_eq(str_count_words(""), 0, "empty string has 0 words")
+    assert_int_eq(str_count_words("hello"), 1, "single word")
+    assert_int_eq(str_count_words("hello world"), 2, "two words")
+    assert_int_eq(str_count_words("  hello  world  "), 2, "extra spaces do not add words")
+    assert_int_eq(str_count_words("one two three four"), 4, "four words")
+    return ""
+}
+
+// ── url_encode / url_decode ──────────────────────────────────────────────────
+
+fn test_url_encode_basic(_: String) -> String {
+    assert_eq(url_encode("hello"), "hello", "plain string unchanged")
+    assert_contains(url_encode("hello world"), "%20", "space encoded as %20")
+    assert_true(str_len(url_encode("hello world")) > str_len("hello world"), "encoded is longer")
+    let encoded: String = url_encode("hello world")
+    let decoded: String = url_decode(encoded)
+    assert_eq(decoded, "hello world", "decode reverses encode")
+    return ""
+}
+
+fn test_url_roundtrip(_: String) -> String {
+    let s: String = "name=hello world&value=42"
+    let encoded: String = url_encode(s)
+    let decoded: String = url_decode(encoded)
+    assert_eq(decoded, s, "url encode/decode roundtrip")
+    assert_true(!str_eq(encoded, s), "encoded differs from original")
+    assert_true(str_len(encoded) >= str_len(s), "encoded is at least as long")
+    return ""
+}
+
+// ── bool_to_str ───────────────────────────────────────────────────────────────
+
+fn test_bool_to_str_basic(_: String) -> String {
+    assert_eq(bool_to_str(true), "true", "true becomes 'true'")
+    assert_eq(bool_to_str(false), "false", "false becomes 'false'")
+    assert_true(str_eq(bool_to_str(1 == 1), "true"), "expression true")
+    assert_true(str_eq(bool_to_str(1 == 2), "false"), "expression false")
+    assert_int_eq(str_len(bool_to_str(true)), 4, "true has length 4")
+    return ""
+}
+
+// ── str_to_bytes / bytes_to_str ───────────────────────────────────────────────
+
+fn test_str_to_bytes_basic(_: String) -> String {
+    let b: String = str_to_bytes("hi")
+    assert_true(str_contains(b, "104"), "h has code 104")
+    assert_true(str_contains(b, "105"), "i has code 105")
+    assert_eq(str_to_bytes(""), "[]", "empty string yields empty array")
+    assert_true(str_starts_with(b, "["), "bytes is JSON array")
+    assert_true(str_ends_with(b, "]"), "bytes is JSON array")
+    return ""
+}
+
+fn test_bytes_roundtrip(_: String) -> String {
+    let s: String = "hello"
+    let b: String = str_to_bytes(s)
+    let s2: String = bytes_to_str(b)
+    assert_eq(s2, s, "bytes roundtrip: hello")
+
+    let s3: String = "ABC"
+    let b3: String = str_to_bytes(s3)
+    let s4: String = bytes_to_str(b3)
+    assert_eq(s4, s3, "bytes roundtrip: ABC")
+
+    assert_eq(bytes_to_str("[]"), "", "empty bytes yields empty string")
+    return ""
+}

tests/suite/src/test_time.el

@@ -0,0 +1,279 @@
+// tests/suite/test_time.el — comprehensive tests for runtime/time.el
+//
+// Covers time_now, now_millis, unix_timestamp, now_ns, time_format, time_to_parts,
+// time_add, time_diff, duration helpers, and uuid_new.
+
+// ── time_now / now_millis / unix_timestamp_ms ─────────────────────────────────
+
+fn test_time_now_basic(_: String) -> String {
+    let t: Int = time_now()
+    // Milliseconds since epoch: must be well past year 2020 (1577836800000)
+    assert_true(t > 1577836800000, "time_now is past 2020-01-01")
+    // Must be before year 2100 (4102444800000)
+    assert_true(t < 4102444800000, "time_now is before 2100-01-01")
+    return ""
+}
+
+fn test_now_millis_basic(_: String) -> String {
+    let t: Int = now_millis()
+    assert_true(t > 1577836800000, "now_millis is past 2020-01-01")
+    assert_true(t < 4102444800000, "now_millis is before 2100-01-01")
+    return ""
+}
+
+fn test_unix_timestamp_ms_basic(_: String) -> String {
+    let t: Int = unix_timestamp_ms()
+    assert_true(t > 1577836800000, "unix_timestamp_ms is past 2020-01-01")
+    assert_true(t < 4102444800000, "unix_timestamp_ms is before 2100-01-01")
+    return ""
+}
+
+fn test_time_now_ms_alias(_: String) -> String {
+    let t: Int = time_now_ms()
+    assert_true(t > 1577836800000, "time_now_ms is past 2020-01-01")
+    assert_true(t < 4102444800000, "time_now_ms is before 2100-01-01")
+    return ""
+}
+
+// ── monotonicity ──────────────────────────────────────────────────────────────
+
+fn test_time_monotonic_now_millis(_: String) -> String {
+    let t1: Int = now_millis()
+    let t2: Int = now_millis()
+    assert_true(t2 >= t1, "second call >= first call (monotonic)")
+    return ""
+}
+
+fn test_time_monotonic_time_now(_: String) -> String {
+    let t1: Int = time_now()
+    let t2: Int = time_now()
+    assert_true(t2 >= t1, "time_now is monotonic across calls")
+    return ""
+}
+
+fn test_time_monotonic_now_ns(_: String) -> String {
+    let t1: Int = now_ns()
+    let t2: Int = now_ns()
+    assert_true(t2 >= t1, "now_ns is monotonic across calls")
+    // ns should be much larger than ms (9 digits difference)
+    assert_true(t1 > 1000000000000000000, "now_ns is in nanosecond scale")
+    return ""
+}
+
+// ── unix_timestamp (seconds) ─────────────────────────────────────────────────
+
+fn test_unix_timestamp_basic(_: String) -> String {
+    let secs: Int = unix_timestamp()
+    // Must be past 2020-01-01 in seconds (1577836800)
+    assert_true(secs > 1577836800, "unix_timestamp is past 2020-01-01")
+    // Must be before 2100-01-01 in seconds (4102444800)
+    assert_true(secs < 4102444800, "unix_timestamp is before 2100-01-01")
+    // seconds are about 1000x smaller than millis
+    let ms: Int = time_now()
+    assert_true(ms > secs, "milliseconds > seconds")
+    return ""
+}
+
+// ── time_to_parts ─────────────────────────────────────────────────────────────
+
+fn test_time_to_parts_basic(_: String) -> String {
+    // Known timestamp: 2024-01-15 12:30:45.123 UTC
+    // 2024-01-15 00:00:00 UTC = epoch + (54 * 365 + 14 leaps) days approximately
+    // Use a precisely known value: 2024-01-15T12:30:45.123Z
+    // epoch_ms = 1705320645123
+    let ts: Int = 1705320645123
+    let parts: String = time_to_parts(ts)
+    assert_eq(json_get(parts, "year"), "2024", "year is 2024")
+    assert_eq(json_get(parts, "month"), "1", "month is 1 (January)")
+    assert_eq(json_get(parts, "day"), "15", "day is 15")
+    assert_eq(json_get(parts, "hour"), "12", "hour is 12")
+    assert_eq(json_get(parts, "minute"), "30", "minute is 30")
+    assert_eq(json_get(parts, "second"), "45", "second is 45")
+    assert_eq(json_get(parts, "ms"), "123", "milliseconds is 123")
+    return ""
+}
+
+fn test_time_to_parts_epoch(_: String) -> String {
+    // Unix epoch: 1970-01-01T00:00:00.000Z = timestamp 0
+    let parts: String = time_to_parts(0)
+    assert_eq(json_get(parts, "year"), "1970", "epoch year is 1970")
+    assert_eq(json_get(parts, "month"), "1", "epoch month is 1")
+    assert_eq(json_get(parts, "day"), "1", "epoch day is 1")
+    assert_eq(json_get(parts, "hour"), "0", "epoch hour is 0")
+    assert_eq(json_get(parts, "minute"), "0", "epoch minute is 0")
+    assert_eq(json_get(parts, "second"), "0", "epoch second is 0")
+    return ""
+}
+
+fn test_time_to_parts_current(_: String) -> String {
+    let ts: Int = time_now()
+    let parts: String = time_to_parts(ts)
+    let year: Int = str_to_int(json_get(parts, "year"))
+    let month: Int = str_to_int(json_get(parts, "month"))
+    let day: Int = str_to_int(json_get(parts, "day"))
+    let hour: Int = str_to_int(json_get(parts, "hour"))
+    let minute: Int = str_to_int(json_get(parts, "minute"))
+    let second: Int = str_to_int(json_get(parts, "second"))
+    assert_true(year >= 2024, "current year >= 2024")
+    assert_true(year < 2100, "current year < 2100")
+    assert_true(month >= 1, "month >= 1")
+    assert_true(month <= 12, "month <= 12")
+    assert_true(day >= 1, "day >= 1")
+    assert_true(day <= 31, "day <= 31")
+    assert_true(hour >= 0, "hour >= 0")
+    assert_true(hour <= 23, "hour <= 23")
+    assert_true(minute >= 0, "minute >= 0")
+    assert_true(minute <= 59, "minute <= 59")
+    assert_true(second >= 0, "second >= 0")
+    assert_true(second <= 59, "second <= 59")
+    return ""
+}
+
+// ── time_format ───────────────────────────────────────────────────────────────
+
+fn test_time_format_iso(_: String) -> String {
+    let ts: Int = 1705320645123
+    let iso: String = time_format(ts, "ISO")
+    assert_starts_with(iso, "2024-01-15", "ISO format starts with correct date")
+    assert_contains(iso, "T12:30:45", "ISO format has correct time")
+    assert_ends_with(iso, "Z", "ISO format ends with Z")
+    assert_contains(iso, "123", "ISO format includes milliseconds")
+    return ""
+}
+
+fn test_time_format_empty(_: String) -> String {
+    let ts: Int = 1705320645123
+    let iso: String = time_format(ts, "")
+    assert_starts_with(iso, "2024-01-15", "empty fmt gives ISO format")
+    assert_ends_with(iso, "Z", "empty fmt gives ISO format ending in Z")
+    return ""
+}
+
+fn test_time_format_strftime(_: String) -> String {
+    let ts: Int = 1705320645123
+    let formatted: String = time_format(ts, "%Y-%m-%d")
+    assert_eq(formatted, "2024-01-15", "strftime %Y-%m-%d")
+    let formatted2: String = time_format(ts, "%H:%M:%S")
+    assert_eq(formatted2, "12:30:45", "strftime %H:%M:%S")
+    return ""
+}
+
+// ── time_add ──────────────────────────────────────────────────────────────────
+
+fn test_time_add_basic(_: String) -> String {
+    let base: Int = 1000000000000
+    assert_int_eq(time_add(base, 1000, "ms"), base + 1000, "add milliseconds")
+    assert_int_eq(time_add(base, 1, "sec"), base + 1000, "add 1 second")
+    assert_int_eq(time_add(base, 1, "min"), base + 60000, "add 1 minute")
+    assert_int_eq(time_add(base, 1, "hour"), base + 3600000, "add 1 hour")
+    assert_int_eq(time_add(base, 1, "day"), base + 86400000, "add 1 day")
+    return ""
+}
+
+fn test_time_add_multiple(_: String) -> String {
+    let base: Int = 1000000000000
+    assert_int_eq(time_add(base, 60, "sec"), base + 60000, "add 60 seconds")
+    assert_int_eq(time_add(base, 24, "hour"), base + 86400000, "add 24 hours = 1 day")
+    assert_int_eq(time_add(base, 0, "sec"), base, "add 0 seconds")
+    assert_int_eq(time_add(base, -1, "sec"), base - 1000, "add negative seconds")
+    return ""
+}
+
+// ── time_diff ─────────────────────────────────────────────────────────────────
+
+fn test_time_diff_basic(_: String) -> String {
+    let t1: Int = 1000000000000
+    let t2: Int = t1 + 5000
+    assert_int_eq(time_diff(t1, t2, "ms"), 5000, "diff in ms")
+    assert_int_eq(time_diff(t1, t2, "sec"), 5, "diff in seconds")
+    return ""
+}
+
+fn test_time_diff_larger(_: String) -> String {
+    let t1: Int = 1000000000000
+    let t2: Int = t1 + 3600000
+    assert_int_eq(time_diff(t1, t2, "min"), 60, "diff of 1 hour in minutes")
+    assert_int_eq(time_diff(t1, t2, "hour"), 1, "diff of 1 hour in hours")
+    assert_int_eq(time_diff(t1, t2, "ms"), 3600000, "diff of 1 hour in ms")
+    return ""
+}
+
+fn test_time_diff_zero(_: String) -> String {
+    let t: Int = 1000000000000
+    assert_int_eq(time_diff(t, t, "ms"), 0, "same timestamp: diff is 0")
+    assert_int_eq(time_diff(t, t, "sec"), 0, "same timestamp: diff in sec is 0")
+    return ""
+}
+
+// ── Duration helpers ──────────────────────────────────────────────────────────
+
+fn test_duration_helpers_basic(_: String) -> String {
+    assert_int_eq(duration_seconds(1), 1000000000, "1 second = 1e9 ns")
+    assert_int_eq(duration_millis(1), 1000000, "1 ms = 1e6 ns")
+    assert_int_eq(duration_nanos(42), 42, "nanos identity")
+    assert_int_eq(duration_to_seconds(1000000000), 1, "1e9 ns = 1 second")
+    assert_int_eq(duration_to_millis(1000000), 1, "1e6 ns = 1 ms")
+    assert_int_eq(duration_to_nanos(42), 42, "nanos identity roundtrip")
+    return ""
+}
+
+fn test_instant_helpers_basic(_: String) -> String {
+    let i: Int = unix_seconds(1000)
+    assert_int_eq(i, 1000000000000, "unix_seconds(1000) = 1e12 ns")
+
+    let ms_i: Int = unix_millis(5000)
+    assert_int_eq(ms_i, 5000000000, "unix_millis(5000) = 5e9 ns")
+
+    assert_int_eq(instant_to_unix_seconds(1000000000000), 1000, "instant to seconds")
+    assert_int_eq(instant_to_unix_millis(5000000000), 5000, "instant to millis")
+    return ""
+}
+
+// ── uuid_new / uuid_v4 ────────────────────────────────────────────────────────
+
+fn test_uuid_new_basic(_: String) -> String {
+    let u: String = uuid_new()
+    assert_int_eq(str_len(u), 36, "UUID has 36 characters")
+    assert_eq(str_char_at(u, 8), "-", "UUID has dash at position 8")
+    assert_eq(str_char_at(u, 13), "-", "UUID has dash at position 13")
+    assert_eq(str_char_at(u, 18), "-", "UUID has dash at position 18")
+    assert_eq(str_char_at(u, 23), "-", "UUID has dash at position 23")
+    return ""
+}
+
+fn test_uuid_uniqueness(_: String) -> String {
+    let u1: String = uuid_new()
+    let u2: String = uuid_new()
+    let u3: String = uuid_v4()
+    assert_false(str_eq(u1, u2), "consecutive UUIDs are different")
+    assert_false(str_eq(u1, u3), "uuid_new and uuid_v4 produce different values")
+    assert_false(str_eq(u2, u3), "three consecutive UUIDs are all different")
+    assert_int_eq(str_len(u3), 36, "uuid_v4 also produces 36-char UUID")
+    return ""
+}
+
+// ── time_from_parts ───────────────────────────────────────────────────────────
+
+fn test_time_from_parts_basic(_: String) -> String {
+    // time_from_parts(secs, ns, tz) = secs * 1000 + ns / 1000000
+    let ts: Int = time_from_parts(1000, 0, "UTC")
+    assert_int_eq(ts, 1000000, "1000 secs = 1000000 ms")
+
+    let ts2: Int = time_from_parts(0, 500000000, "UTC")
+    assert_int_eq(ts2, 500, "500ms in nanoseconds -> 500ms")
+
+    let ts3: Int = time_from_parts(1705320645, 123000000, "UTC")
+    assert_int_eq(ts3, 1705320645123, "known timestamp with ms component")
+    return ""
+}
+
+// ── instant_to_iso8601 ────────────────────────────────────────────────────────
+
+fn test_instant_to_iso8601_basic(_: String) -> String {
+    let ts_ms: Int = 1705320645123
+    let ts_ns: Int = ts_ms * 1000000
+    let iso: String = instant_to_iso8601(ts_ns)
+    assert_starts_with(iso, "2024-01-15", "instant_to_iso8601 correct date")
+    assert_ends_with(iso, "Z", "instant_to_iso8601 ends with Z")
+    return ""
+}

tools/install.sh

@@ -0,0 +1,127 @@
+#!/usr/bin/env bash
+# install.sh — install El as a proper local framework tool.
+#
+# Copies the compiler binary, runtime source files, headers, and stdlib
+# from the local source tree into the install prefix. After install,
+# El programs can be built against an installed, stable copy of the runtime.
+#
+# Usage:
+#   ./tools/install.sh
+#   ./tools/install.sh --prefix /opt/el
+#
+# Environment:
+#   EL_HOME   Override install prefix (same as --prefix)
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+EL_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"
+
+PREFIX="${EL_HOME:-/usr/local/el}"
+
+# Parse --prefix flag
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --prefix)
+            PREFIX="$2"
+            shift 2
+            ;;
+        --prefix=*)
+            PREFIX="${1#--prefix=}"
+            shift
+            ;;
+        *)
+            echo "Unknown argument: $1" >&2
+            echo "Usage: $0 [--prefix <path>]" >&2
+            exit 1
+            ;;
+    esac
+done
+
+BIN_DIR="${PREFIX}/bin"
+RUNTIME_DIR="${PREFIX}/runtime"
+INCLUDE_DIR="${PREFIX}/include"
+LIB_DIR="${PREFIX}/lib"
+
+ELC_SRC="${EL_ROOT}/dist/platform/elc"
+RUNTIME_SRC="${EL_ROOT}/el-compiler/runtime"
+STDLIB_SRC="${EL_ROOT}/runtime"
+
+echo "==> Installing El framework to ${PREFIX}"
+echo "    bin:     ${BIN_DIR}"
+echo "    runtime: ${RUNTIME_DIR}"
+echo "    include: ${INCLUDE_DIR}"
+echo "    lib:     ${LIB_DIR}"
+echo
+
+# Create directories
+mkdir -p "${BIN_DIR}" "${RUNTIME_DIR}" "${INCLUDE_DIR}" "${LIB_DIR}"
+
+# 1. Install elc binary
+if [[ ! -f "${ELC_SRC}" ]]; then
+    echo "Error: elc binary not found at ${ELC_SRC}" >&2
+    echo "Build it first or run from the el repo root." >&2
+    exit 1
+fi
+install -m 755 "${ELC_SRC}" "${BIN_DIR}/elc"
+echo "    installed: ${BIN_DIR}/elc"
+
+# 2. Install runtime .el files
+for f in "${STDLIB_SRC}"/*.el; do
+    [[ -f "$f" ]] || continue
+    install -m 644 "$f" "${RUNTIME_DIR}/$(basename "$f")"
+done
+echo "    installed: ${RUNTIME_DIR}/*.el  ($(ls "${STDLIB_SRC}"/*.el | wc -l | tr -d ' ') files)"
+
+# 3. Install headers
+for header in el_seed.h el_runtime.h; do
+    src="${RUNTIME_SRC}/${header}"
+    if [[ -f "${src}" ]]; then
+        install -m 644 "${src}" "${INCLUDE_DIR}/${header}"
+        echo "    installed: ${INCLUDE_DIR}/${header}"
+    fi
+done
+
+# 4. Build libel.a from el_seed.c + el_runtime.c
+echo "    compiling libel.a..."
+TMP_DIR="$(mktemp -d)"
+trap 'rm -rf "${TMP_DIR}"' EXIT
+
+cc -std=c11 -O2 -I"${RUNTIME_SRC}" -c "${RUNTIME_SRC}/el_seed.c"   -o "${TMP_DIR}/el_seed.o"
+cc -std=c11 -O2 -I"${RUNTIME_SRC}" -c "${RUNTIME_SRC}/el_runtime.c" -o "${TMP_DIR}/el_runtime.o"
+ar rcs "${LIB_DIR}/libel.a" "${TMP_DIR}/el_seed.o" "${TMP_DIR}/el_runtime.o"
+echo "    installed: ${LIB_DIR}/libel.a"
+
+# 5. Generate stdlib.el with absolute paths to installed runtime files
+STDLIB_OUT="${PREFIX}/stdlib.el"
+{
+    echo "// stdlib.el — El standard library (installed at ${PREFIX})"
+    echo "// Generated by tools/install.sh — do not edit by hand."
+    echo "// Import this file to get the full El runtime:"
+    echo "//   import \"${PREFIX}/stdlib.el\""
+    echo
+    for f in "${STDLIB_SRC}"/*.el; do
+        [[ -f "$f" ]] || continue
+        base="$(basename "$f")"
+        # Skip stdlib.el itself to avoid circular import
+        [[ "${base}" == "stdlib.el" ]] && continue
+        # Skip test.el — dev-only
+        [[ "${base}" == "test.el" ]] && continue
+        echo "import \"${RUNTIME_DIR}/${base}\""
+    done
+} > "${STDLIB_OUT}"
+echo "    installed: ${STDLIB_OUT}"
+
+echo
+echo "==> El installed to ${PREFIX}"
+echo
+echo "Add ${BIN_DIR} to your PATH:"
+echo "    export PATH=\"${BIN_DIR}:\$PATH\""
+echo
+echo "To use the stdlib in your El programs:"
+echo "    import \"${PREFIX}/stdlib.el\""
+echo
+echo "To link El programs against the installed runtime:"
+echo "    elc src/main.el > dist/main.c"
+echo "    cc -std=c11 -O2 -I${INCLUDE_DIR} -o dist/main dist/main.c ${LIB_DIR}/libel.a -lcurl -lpthread"
+echo

tools/lsp/README.md

@@ -0,0 +1,198 @@
+# El LSP — Language Server for El
+
+Full Language Server Protocol implementation for the El programming language.
+
+## Features
+
+| Feature | Status |
+|---------|--------|
+| Syntax highlighting | Full TextMate grammar |
+| Completions | Builtins (130+), user-defined fns, keywords, types |
+| Hover | Signatures + descriptions for all builtins and user fns |
+| Go-to-definition | Jump to `fn name(` in the open document |
+| Diagnostics | Unclosed braces/parens/brackets, unterminated strings |
+| Document sync | Full (re-sends entire document on every change) |
+
+## Building
+
+### Prerequisites
+
+- The `elc` compiler binary at `dist/platform/elc` (built from the repo root)
+- `cc` (clang or gcc), `libcurl`, `pthreads`
+
+### Build
+
+```bash
+# From the el repo root:
+./tools/lsp/build.sh
+
+# Or with a custom elc path:
+ELC=/path/to/elc ./tools/lsp/build.sh
+```
+
+Output: `tools/lsp/dist/el-lsp`
+
+### Install system-wide
+
+```bash
+sudo cp tools/lsp/dist/el-lsp /usr/local/bin/el-lsp
+```
+
+## VSCode Extension
+
+### Development install (recommended)
+
+1. Build the binary first (see above).
+2. Install the npm dependency:
+   ```bash
+   cd tools/lsp/vscode-extension
+   npm install
+   ```
+3. Open `tools/lsp/vscode-extension/` in VSCode.
+4. Press **F5** — this launches the Extension Development Host.
+5. Open any `.el` file in the dev host window.
+
+### Package as .vsix
+
+```bash
+npm install -g @vscode/vsce
+cd tools/lsp/vscode-extension
+vsce package
+# Produces: el-language-1.0.0.vsix
+```
+
+Install the .vsix:
+```bash
+code --install-extension el-language-1.0.0.vsix
+```
+
+### Configuration
+
+| Setting | Default | Description |
+|---------|---------|-------------|
+| `el.lspPath` | (bundled) | Path to `el-lsp` binary. Empty = use `../dist/el-lsp`. |
+| `el.trace.server` | `off` | LSP message tracing. Set to `verbose` to see all messages. |
+
+## Neovim / other editors
+
+Any editor that supports LSP can use `el-lsp`. Example configuration for
+Neovim with `nvim-lspconfig`:
+
+```lua
+local lspconfig = require('lspconfig')
+local configs   = require('lspconfig.configs')
+
+if not configs.el then
+  configs.el = {
+    default_config = {
+      cmd        = { 'el-lsp' },
+      filetypes  = { 'el' },
+      root_dir   = lspconfig.util.root_pattern('.git', '*.el'),
+      settings   = {},
+    },
+  }
+end
+
+lspconfig.el.setup({})
+```
+
+Add to `ftdetect/el.vim`:
+```vim
+au BufRead,BufNewFile *.el set filetype=el
+```
+
+## Wire protocol
+
+El LSP communicates over stdin/stdout using standard LSP framing:
+
+```
+Content-Length: <N>\r\n
+\r\n
+<N bytes of UTF-8 JSON>
+```
+
+The `__read_n(n: Int) -> String` primitive in `el_runtime.c` reads exactly
+`n` bytes from stdin — needed because `readline()` stops at `\n` and LSP
+JSON bodies are not newline-terminated. `__print_raw(s: String)` writes with
+`fwrite + fflush` to preserve embedded `\r\n` in headers.
+
+## Smoke test
+
+After building, verify the server responds to `initialize`:
+
+```bash
+python3 - << 'PY'
+import subprocess, json
+
+def frame(obj):
+    body = json.dumps(obj).encode()
+    return f"Content-Length: {len(body)}\r\n\r\n".encode() + body
+
+def read_response(proc):
+    hdr = b""
+    while not hdr.endswith(b"\r\n\r\n"):
+        hdr += proc.stdout.read(1)
+    cl = int([l for l in hdr.decode().split("\r\n") if "Content-Length" in l][0].split(": ")[1])
+    return json.loads(proc.stdout.read(cl))
+
+proc = subprocess.Popen(["./dist/el-lsp"], stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+proc.stdin.write(frame({"jsonrpc":"2.0","id":1,"method":"initialize","params":{"capabilities":{}}}))
+proc.stdin.flush()
+r = read_response(proc)
+print("Server name:", r["result"]["serverInfo"]["name"])
+print("Capabilities:", list(r["result"]["capabilities"].keys()))
+proc.stdin.write(frame({"jsonrpc":"2.0","method":"exit","params":{}}))
+proc.stdin.flush()
+proc.wait()
+print("OK")
+PY
+```
+
+## Architecture
+
+```
+el-lsp.el
+  lsp_read_message()      reads header bytes one-by-one, then __read_n(body_len)
+  lsp_write_message()     __print_raw("Content-Length: N\r\n\r\n" + json)
+  lsp_dispatch()          routes method string to handler
+  lsp_builtin_catalog()   [String] of "name|signature|description" entries
+  lsp_extract_fns()       scan source for "fn name(" patterns
+  lsp_word_at()           expand identifier under cursor
+  lsp_compute_diagnostics() scan for unclosed brackets + unterminated strings
+```
+
+## Files
+
+```
+tools/lsp/
+  el-lsp.el                   LSP server source (El language)
+  build.sh                    Build script
+  README.md                   This file
+  dist/
+    el-lsp                    Compiled binary (after build)
+    el-lsp.c                  Generated C (after build)
+  vscode-extension/
+    extension.js              Extension entry point
+    package.json              Extension manifest
+    language-configuration.json  Bracket matching, comment config
+    syntaxes/
+      el.tmGrammar.json       TextMate syntax grammar
+    .vscode/
+      launch.json             F5 debug configuration
+      tasks.json              Pre-launch npm install task
+```
+
+## Runtime additions
+
+Two new primitives added to `el-compiler/runtime/`:
+
+### `__read_n(n: Int) -> String`
+Reads exactly `n` bytes from stdin using `fread`. Returns `""` on EOF.
+Required for reading JSON-RPC message bodies.
+
+### `__print_raw(s: String) -> Void`
+Writes a string to stdout using `fwrite + fflush`. Preserves embedded
+`\r\n` bytes exactly. Required for LSP Content-Length headers.
+
+Both are declared in `el_runtime.h` and registered in the `builtin_arity`
+table in `el-compiler/src/codegen.el`.

tools/lsp/vscode-extension/.vscode/launch.json

@@ -0,0 +1,31 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Launch Extension (Extension Development Host)",
+      "type": "extensionHost",
+      "request": "launch",
+      "args": [
+        "--extensionDevelopmentPath=${workspaceFolder}"
+      ],
+      "outFiles": [
+        "${workspaceFolder}/**/*.js"
+      ],
+      "preLaunchTask": "npm: install",
+      "env": {
+        "EL_LSP_LOG": "1"
+      }
+    },
+    {
+      "name": "Attach to el-lsp process",
+      "type": "node",
+      "request": "attach",
+      "port": 6009,
+      "restart": true,
+      "timeout": 10000,
+      "outFiles": [
+        "${workspaceFolder}/**/*.js"
+      ]
+    }
+  ]
+}

tools/lsp/vscode-extension/.vscode/tasks.json

@@ -0,0 +1,16 @@
+{
+  "version": "2.0.0",
+  "tasks": [
+    {
+      "type": "npm",
+      "script": "install",
+      "label": "npm: install",
+      "detail": "Install vscode-languageclient dependency",
+      "group": "build",
+      "presentation": {
+        "reveal": "silent"
+      },
+      "problemMatcher": []
+    }
+  ]
+}

tools/lsp/vscode-extension/extension.js

@@ -0,0 +1,150 @@
+// tools/lsp/vscode-extension/extension.js
+//
+// El Language VSCode extension — Language Client
+//
+// Launches the el-lsp binary as a child process and connects VSCode's
+// Language Client to it over stdin/stdout (JSON-RPC 2.0 + Content-Length).
+//
+// Capabilities provided by el-lsp:
+//   - textDocumentSync (full)
+//   - completionProvider  — builtins + user fns + keywords
+//   - hoverProvider       — signatures + descriptions
+//   - definitionProvider  — go-to-def for user-defined fns
+//   - diagnostics         — unclosed braces/parens, unterminated strings
+//
+// Setup (development):
+//   1. cd tools/lsp && ./build.sh          (builds dist/el-lsp)
+//   2. cd vscode-extension && npm install  (installs vscode-languageclient)
+//   3. Open vscode-extension/ in VSCode
+//   4. Press F5                            (launches Extension Development Host)
+//   5. Open any .el file
+//
+// Package as .vsix:
+//   npm install -g @vscode/vsce
+//   cd tools/lsp/vscode-extension && vsce package
+
+'use strict';
+
+const path = require('path');
+const fs   = require('fs');
+const { workspace, window, ExtensionContext } = require('vscode');
+const {
+    LanguageClient,
+    TransportKind,
+} = require('vscode-languageclient/node');
+
+/** @type {LanguageClient | undefined} */
+let client;
+
+/**
+ * activate — entry point called when any .el file is first opened.
+ *
+ * @param {ExtensionContext} context
+ */
+function activate(context) {
+    // ── Resolve el-lsp binary ────────────────────────────────────────────
+    const config = workspace.getConfiguration('el');
+
+    // Default path resolution (tries in order):
+    //   1. el.lspPath setting (user override)
+    //   2. dist/el-lsp alongside the extension dir (packaged install)
+    //   3. The canonical source-tree location
+    const CANONICAL_LSP = '/Users/will/Development/neuron-technologies/foundation/el/tools/lsp/dist/el-lsp';
+    const defaultLspPath = (() => {
+        const sibling = path.join(context.extensionPath, 'dist', 'el-lsp');
+        if (fs.existsSync(sibling)) return sibling;
+        return CANONICAL_LSP;
+    })();
+    const serverPath = config.get('lspPath') || defaultLspPath;
+
+    if (!fs.existsSync(serverPath)) {
+        window.showErrorMessage(
+            `El Language Server binary not found at: ${serverPath}\n` +
+            `Run tools/lsp/build.sh to build it, then reload VSCode.\n` +
+            `Or set "el.lspPath" in settings to the correct path.`
+        );
+        return;
+    }
+
+    // ── Server options (start el-lsp as child process) ───────────────────
+    /** @type {import('vscode-languageclient/node').ServerOptions} */
+    const serverOptions = {
+        run: {
+            command:   serverPath,
+            transport: TransportKind.stdio,
+            options:   { env: { ...process.env } },
+        },
+        debug: {
+            command:   serverPath,
+            transport: TransportKind.stdio,
+            options: {
+                env: { ...process.env },
+                // Redirect el-lsp stderr to VSCode's Output panel in debug mode.
+            },
+        },
+    };
+
+    // ── Client options ───────────────────────────────────────────────────
+    /** @type {import('vscode-languageclient/node').LanguageClientOptions} */
+    const clientOptions = {
+        // Activate for all .el files (file:// and untitled: schemes).
+        documentSelector: [
+            { scheme: 'file',     language: 'el' },
+            { scheme: 'untitled', language: 'el' },
+        ],
+        synchronize: {
+            // Fire fileEvents so the client resends on disk changes outside VSCode.
+            fileEvents: workspace.createFileSystemWatcher('**/*.el'),
+        },
+        outputChannelName: 'El Language Server',
+        // Trace LSP messages to the Output panel for debugging.
+        // Set "el.trace.server": "verbose" in settings to enable.
+        traceOutputChannel: window.createOutputChannel('El LSP Trace'),
+    };
+
+    // ── Create and start client ──────────────────────────────────────────
+    client = new LanguageClient(
+        'el-language-server',
+        'El Language Server',
+        serverOptions,
+        clientOptions,
+    );
+
+    // Register the client so it is disposed when the extension deactivates.
+    context.subscriptions.push(client);
+
+    client.start().then(() => {
+        // Show a discrete status bar item while the server is active.
+        const status = window.createStatusBarItem(1);
+        status.text    = '$(symbol-misc) El LSP';
+        status.tooltip = 'El Language Server is running';
+        status.command = 'el.restartServer';
+        status.show();
+        context.subscriptions.push(status);
+    }).catch((err) => {
+        window.showErrorMessage(`El Language Server failed to start: ${err.message}`);
+    });
+
+    // ── Commands ─────────────────────────────────────────────────────────
+    context.subscriptions.push(
+        require('vscode').commands.registerCommand('el.restartServer', () => {
+            if (client) {
+                client.stop().then(() => client.start());
+                window.showInformationMessage('El Language Server restarted.');
+            }
+        })
+    );
+}
+
+/**
+ * deactivate — called when the extension is unloaded.
+ * Sends LSP shutdown + exit to the server process.
+ */
+function deactivate() {
+    if (!client) {
+        return undefined;
+    }
+    return client.stop();
+}
+
+module.exports = { activate, deactivate };

tools/lsp/vscode-extension/language-configuration.json

@@ -0,0 +1,26 @@
+{
+  "comments": {
+    "lineComment": "//"
+  },
+  "brackets": [
+    ["{", "}"],
+    ["[", "]"],
+    ["(", ")"]
+  ],
+  "autoClosingPairs": [
+    { "open": "{", "close": "}" },
+    { "open": "[", "close": "]" },
+    { "open": "(", "close": ")" },
+    { "open": "\"", "close": "\"", "notIn": ["string"] }
+  ],
+  "surroundingPairs": [
+    ["{", "}"],
+    ["[", "]"],
+    ["(", ")"],
+    ["\"", "\""]
+  ],
+  "indentationRules": {
+    "increaseIndentPattern": "\\{[^}]*$",
+    "decreaseIndentPattern": "^\\s*}"
+  }
+}

tools/lsp/vscode-extension/package.json

@@ -0,0 +1,93 @@
+{
+  "name": "el-language",
+  "displayName": "El Language",
+  "description": "El language support \u2014 syntax highlighting, completions, hover, go-to-definition, and diagnostics",
+  "version": "1.0.0",
+  "publisher": "neuron-technologies",
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/neuron-technologies/foundation"
+  },
+  "engines": {
+    "vscode": "^1.75.0"
+  },
+  "categories": [
+    "Programming Languages",
+    "Linters",
+    "Other"
+  ],
+  "keywords": [
+    "el",
+    "el-lang",
+    "language-server",
+    "lsp",
+    "neuron"
+  ],
+  "activationEvents": [
+    "onLanguage:el"
+  ],
+  "contributes": {
+    "languages": [
+      {
+        "id": "el",
+        "aliases": [
+          "El",
+          "el-lang"
+        ],
+        "extensions": [
+          ".el",
+          ".elh"
+        ],
+        "configuration": "./language-configuration.json"
+      }
+    ],
+    "grammars": [
+      {
+        "language": "el",
+        "scopeName": "source.el",
+        "path": "./syntaxes/el.tmGrammar.json"
+      }
+    ],
+    "configuration": {
+      "type": "object",
+      "title": "El Language",
+      "properties": {
+        "el.lspPath": {
+          "type": "string",
+          "default": "",
+          "description": "Absolute path to the el-lsp binary. Leave empty to use the binary bundled with the extension (../dist/el-lsp)."
+        },
+        "el.trace.server": {
+          "type": "string",
+          "enum": [
+            "off",
+            "messages",
+            "verbose"
+          ],
+          "default": "off",
+          "description": "Trace LSP messages between VSCode and el-lsp (visible in Output \u2192 El LSP Trace)."
+        }
+      }
+    },
+    "commands": [
+      {
+        "command": "el.restartServer",
+        "title": "El: Restart Language Server"
+      }
+    ]
+  },
+  "main": "./extension.js",
+  "dependencies": {
+    "vscode-languageclient": "^8.1.0"
+  },
+  "devDependencies": {
+    "@types/vscode": "^1.75.0",
+    "@vscode/vsce": "^2.22.0"
+  },
+  "scripts": {
+    "vscode:prepublish": "echo 'no transpile step required'",
+    "package": "vsce package",
+    "install-dev": "npm install && code --install-extension el-language-1.0.0.vsix 2>/dev/null || true"
+  }
+}

tools/lsp/vscode-extension/syntaxes/el.tmGrammar.json

@@ -0,0 +1,175 @@
+{
+  "$schema": "https://raw.githubusercontent.com/martinring/tmlanguage/master/tmlanguage.json",
+  "name": "El",
+  "scopeName": "source.el",
+  "fileTypes": ["el"],
+  "patterns": [
+    { "include": "#comments" },
+    { "include": "#strings" },
+    { "include": "#function-definition" },
+    { "include": "#builtin-functions" },
+    { "include": "#keywords-control" },
+    { "include": "#keywords-declaration" },
+    { "include": "#keywords-other" },
+    { "include": "#types" },
+    { "include": "#type-annotations" },
+    { "include": "#constants" },
+    { "include": "#numbers" },
+    { "include": "#operators" },
+    { "include": "#range-operator" },
+    { "include": "#function-call" },
+    { "include": "#identifiers" }
+  ],
+  "repository": {
+
+    "comments": {
+      "name": "comment.line.double-slash.el",
+      "match": "//.*$"
+    },
+
+    "strings": {
+      "name": "string.quoted.double.el",
+      "begin": "\"",
+      "end": "\"",
+      "patterns": [
+        {
+          "name": "constant.character.escape.el",
+          "match": "\\\\[nrt\\\\\"'0]"
+        },
+        {
+          "name": "constant.character.escape.hex.el",
+          "match": "\\\\x[0-9a-fA-F]{2}"
+        }
+      ]
+    },
+
+    "function-definition": {
+      "comment": "fn keyword + function name — name gets entity.name.function",
+      "match": "\\b(fn)\\s+([a-zA-Z_][a-zA-Z0-9_]*)\\s*(?=\\()",
+      "captures": {
+        "1": { "name": "keyword.declaration.function.el" },
+        "2": { "name": "entity.name.function.el" }
+      }
+    },
+
+    "builtin-functions": {
+      "comment": "Well-known El builtins get support.function scope for distinct colour",
+      "name": "support.function.builtin.el",
+      "match": "\\b(println|print|readline|str_eq|str_len|str_concat|str_slice|str_contains|str_starts_with|str_ends_with|str_replace|str_to_upper|str_to_lower|str_trim|str_lstrip|str_rstrip|str_index_of|str_last_index_of|str_split|str_split_lines|str_split_n|str_join|str_char_at|str_char_code|str_pad_left|str_pad_right|str_repeat|str_reverse|str_strip_prefix|str_strip_suffix|str_strip_chars|str_count|str_count_lines|str_find_chars|str_upper|str_lower|int_to_str|str_to_int|float_to_str|str_to_float|int_to_float|float_to_int|format_float|decimal_round|bool_to_str|el_abs|el_max|el_min|math_sqrt|math_log|math_ln|math_sin|math_cos|math_pi|el_list_empty|el_list_append|el_list_len|el_list_get|el_list_clone|list_push|list_push_front|list_join|list_range|el_map_get|el_map_set|el_get_field|state_set|state_get|state_del|state_keys|json_get|json_get_string|json_get_int|json_get_float|json_get_bool|json_get_raw|json_set|json_parse|json_stringify|json_array_len|json_array_get|json_array_get_string|fs_read|fs_write|fs_list|fs_exists|fs_mkdir|http_get|http_post|http_post_json|http_get_with_headers|http_post_with_headers|http_serve|http_serve_v2|http_response|url_encode|url_decode|time_now|time_now_utc|sleep_secs|sleep_ms|time_format|time_add|time_diff|now|unix_seconds|unix_millis|uuid_new|uuid_v4|env|args|exit_program|exec_command|exec_capture|sha256_hex|hmac_sha256_hex|base64_encode|base64_decode|base64url_encode|base64url_decode|llm_call|llm_call_system|llm_call_agentic|llm_vision|llm_models|llm_register_tool|engram_node|engram_get_node|engram_strengthen|engram_forget|engram_search|engram_connect|engram_activate|engram_save|engram_load|engram_node_count|engram_edge_count|engram_neighbors|engram_search_json|engram_stats_json|dharma_connect|dharma_send|dharma_activate|dharma_emit|dharma_field|dharma_peers|native_list_empty|native_list_append|native_list_len|native_list_get|native_list_clone|native_string_chars|native_int_to_str)\\b(?=\\s*\\()"
+    },
+
+    "keywords-control": {
+      "name": "keyword.control.el",
+      "match": "\\b(if|else|while|for|in|return|match|break|continue)\\b"
+    },
+
+    "keywords-declaration": {
+      "name": "keyword.declaration.el",
+      "match": "\\b(fn|let|type|enum|import|from|as|extern)\\b"
+    },
+
+    "keywords-other": {
+      "name": "keyword.other.el",
+      "match": "\\b(cgi|vessel|activate|where|sealed|with|test|seed|assert|protocol|impl|retry|times|fallback|reason|parallel|trace|requires|deploy|to|via|target|manager|engine|accessor)\\b"
+    },
+
+    "types": {
+      "comment": "Built-in El primitive types",
+      "name": "support.type.primitive.el",
+      "match": "\\b(String|Int|Float|Bool|Void|Any|Instant|Duration|Map|List)\\b"
+    },
+
+    "type-annotations": {
+      "comment": "Highlight type annotations after : in let and fn params",
+      "patterns": [
+        {
+          "match": ":\\s*([A-Z][a-zA-Z0-9_<>, ]*)(?=\\s*[,)={\\]]|\\s*->)",
+          "captures": {
+            "1": { "name": "support.type.el" }
+          }
+        },
+        {
+          "match": "->\\s*([A-Z][a-zA-Z0-9_<>, ]*)",
+          "captures": {
+            "0": { "name": "keyword.operator.arrow.el" },
+            "1": { "name": "support.type.return.el" }
+          }
+        }
+      ]
+    },
+
+    "constants": {
+      "patterns": [
+        {
+          "name": "constant.language.boolean.el",
+          "match": "\\b(true|false)\\b"
+        },
+        {
+          "name": "constant.language.null.el",
+          "match": "\\bnull\\b"
+        }
+      ]
+    },
+
+    "numbers": {
+      "patterns": [
+        {
+          "name": "constant.numeric.float.el",
+          "match": "-?\\b[0-9]+\\.[0-9]+\\b"
+        },
+        {
+          "name": "constant.numeric.integer.el",
+          "match": "-?\\b[0-9]+\\b"
+        }
+      ]
+    },
+
+    "range-operator": {
+      "name": "keyword.operator.range.el",
+      "match": "\\.\\."
+    },
+
+    "operators": {
+      "patterns": [
+        {
+          "name": "keyword.operator.comparison.el",
+          "match": "(==|!=|<=|>=)"
+        },
+        {
+          "name": "keyword.operator.comparison.el",
+          "match": "(?<![<>-])([<>])(?![>=])"
+        },
+        {
+          "name": "keyword.operator.logical.el",
+          "match": "(&&|\\|\\||!(?!=))"
+        },
+        {
+          "name": "keyword.operator.assignment.el",
+          "match": "(?<![=!<>])=(?!=)"
+        },
+        {
+          "name": "keyword.operator.arithmetic.el",
+          "match": "[+\\-*/%]"
+        },
+        {
+          "name": "keyword.operator.arrow.el",
+          "match": "->"
+        }
+      ]
+    },
+
+    "function-call": {
+      "comment": "Function calls: identifier immediately followed by (",
+      "match": "\\b([a-zA-Z_][a-zA-Z0-9_]*)\\s*(?=\\()",
+      "captures": {
+        "1": { "name": "entity.name.function.call.el" }
+      }
+    },
+
+    "identifiers": {
+      "comment": "Catch-all for remaining identifiers",
+      "name": "variable.other.el",
+      "match": "\\b[a-zA-Z_][a-zA-Z0-9_]*\\b"
+    }
+  }
+}

tools/new-project.sh

@@ -0,0 +1,164 @@
+#!/usr/bin/env bash
+# new-project.sh — scaffold a new El project.
+#
+# Usage:
+#   ./tools/new-project.sh <project-name>
+#
+# Creates:
+#   <project-name>/
+#     src/main.el      — hello world entry point
+#     build.sh         — build script using elc + el_runtime.c
+#     README.md        — minimal project docs
+
+set -euo pipefail
+
+if [[ $# -lt 1 ]]; then
+    echo "Usage: $0 <project-name>" >&2
+    exit 1
+fi
+
+NAME="$1"
+
+if [[ -e "${NAME}" ]]; then
+    echo "Error: '${NAME}' already exists." >&2
+    exit 1
+fi
+
+# Discover elc — prefer PATH, fall back to the local foundation/el tree
+ELC="elc"
+if ! command -v elc >/dev/null 2>&1; then
+    # Try a sibling or parent path convention
+    SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+    LOCAL_ELC="${SCRIPT_DIR}/../dist/platform/elc"
+    if [[ -x "${LOCAL_ELC}" ]]; then
+        ELC="$(cd "$(dirname "${LOCAL_ELC}")" && pwd)/$(basename "${LOCAL_ELC}")"
+    else
+        echo "Warning: elc not found in PATH or at ${LOCAL_ELC}" >&2
+        echo "         The generated build.sh may need manual adjustment." >&2
+        ELC="elc"
+    fi
+fi
+
+# Discover el_runtime.c
+EL_RUNTIME=""
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+LOCAL_RUNTIME="${SCRIPT_DIR}/../el-compiler/runtime/el_runtime.c"
+if [[ -f "${LOCAL_RUNTIME}" ]]; then
+    EL_RUNTIME="$(cd "$(dirname "${LOCAL_RUNTIME}")" && pwd)/$(basename "${LOCAL_RUNTIME}")"
+    EL_INCLUDE="$(dirname "${EL_RUNTIME}")"
+else
+    # Check installed location
+    if [[ -f "/usr/local/el/lib/libel.a" ]]; then
+        EL_RUNTIME_LINK="-L/usr/local/el/lib -lel"
+        EL_INCLUDE="/usr/local/el/include"
+    fi
+    EL_RUNTIME="${EL_RUNTIME_LINK:-}"
+fi
+
+echo "==> Scaffolding El project: ${NAME}"
+
+mkdir -p "${NAME}/src" "${NAME}/dist"
+
+# src/main.el
+cat > "${NAME}/src/main.el" <<'ELEOF'
+// main.el — entry point for this El program.
+
+fn run() -> String {
+    println("hello from El!")
+    return ""
+}
+
+run()
+ELEOF
+
+# build.sh — adapts to whether we found elc/runtime locally or installed
+if [[ -n "${EL_RUNTIME}" && -f "${EL_RUNTIME}" ]]; then
+    # Local source tree runtime
+    EL_INCLUDE_DIR="$(dirname "${EL_RUNTIME}")"
+    cat > "${NAME}/build.sh" <<BUILDEOF
+#!/usr/bin/env bash
+# build.sh — build ${NAME}
+set -euo pipefail
+
+ELC="${ELC}"
+EL_RUNTIME="${EL_RUNTIME}"
+EL_INCLUDE="${EL_INCLUDE_DIR}"
+
+mkdir -p dist
+
+echo "==> Compiling El -> C"
+"\${ELC}" src/main.el > dist/main.c
+
+echo "==> Compiling C -> binary"
+cc -std=c11 -O2 -I"\${EL_INCLUDE}" -o dist/${NAME} dist/main.c "\${EL_RUNTIME}" -lcurl -lpthread
+
+echo "==> Built: dist/${NAME}"
+BUILDEOF
+else
+    # Installed framework
+    cat > "${NAME}/build.sh" <<BUILDEOF
+#!/usr/bin/env bash
+# build.sh — build ${NAME}
+# Requires El installed via tools/install.sh (elc in PATH, /usr/local/el/lib/libel.a)
+set -euo pipefail
+
+ELC="\${ELC:-elc}"
+EL_PREFIX="\${EL_HOME:-/usr/local/el}"
+
+mkdir -p dist
+
+echo "==> Compiling El -> C"
+"\${ELC}" src/main.el > dist/main.c
+
+echo "==> Compiling C -> binary"
+cc -std=c11 -O2 -I"\${EL_PREFIX}/include" -o dist/${NAME} dist/main.c -L"\${EL_PREFIX}/lib" -lel -lcurl -lpthread
+
+echo "==> Built: dist/${NAME}"
+BUILDEOF
+fi
+
+chmod +x "${NAME}/build.sh"
+
+# README.md
+cat > "${NAME}/README.md" <<READMEEOF
+# ${NAME}
+
+An El language project.
+
+## Build
+
+\`\`\`bash
+./build.sh
+\`\`\`
+
+## Run
+
+\`\`\`bash
+./dist/${NAME}
+\`\`\`
+
+## Structure
+
+\`\`\`
+src/main.el      — entry point
+build.sh         — build script
+dist/            — compiled output (gitignored)
+\`\`\`
+READMEEOF
+
+# .gitignore
+cat > "${NAME}/.gitignore" <<'IGNEOF'
+dist/
+*.c
+IGNEOF
+
+echo
+echo "==> Created ${NAME}/"
+echo "    src/main.el"
+echo "    build.sh"
+echo "    README.md"
+echo "    .gitignore"
+echo
+echo "To build:"
+echo "    cd ${NAME} && ./build.sh"
+echo