runtime: put el_runtime.c on a ratchet, and actually run the guards

scripts/check-single-runtime.sh guards against el_runtime.c being COPIED — it
was written after a lagging fork shipped to prod and dropped learned hebb edges.
Nothing guarded against it GROWING. So it grew: 10,607 -> 20,527 lines, 94% in
3.5 months, the whole time under an explicit commit-message promise that it was
a temporary shim about to be deleted.

Worse, the copy guard was never wired in. Its own footer described the CI
wire-in as a TODO, and the TODO had never been done — the script existed but ran
nowhere, in no workflow and in no hook, so it had caught nothing for as long as
it has been in the tree. A guard that does not run is a comment.

This adds the missing guard and runs both.

  * lang/runtime/BUDGET — a RATCHET, not a limit. max_lines is set at the
    current 20,527 with NO headroom: the file cannot grow by one line. A second
    cap, max_engram_fns (279), counts top-level engram_/eg_/cog_ definitions in
    it — ~47.5% of the file is engram code and engram already owns six sibling
    .c files, so this is the scoreboard for moving it out. Both may only go DOWN.

  * scripts/check-runtime-growth.sh — enforces the ratchet, and three
    invariants that keep the multi-file runtime honest: every .c in
    lang/runtime/ is either in SOURCES or explicitly platform-optional (an
    unaccounted .c is compiled by nothing and is silently dead); install.sh's
    hardcoded download list matches SOURCES (it cannot call the helper — it
    runs where there is no checkout — so that copy is checked, not trusted);
    and an advisory nudge to lower the budget when you have earned it.

  * Both guards now run as early steps in ci-dev.yaml, ci-stage.yaml and
    sdk-release.yaml, and in .githooks/pre-commit.

The failure message is the point. The guard that existed said what was wrong but
not where the code should go, which makes it easy to "fix" by arguing with the
guard. This one names the destination: the concern-owning .c, or a new .c plus
one line in SOURCES, or c_source in a program's manifest.el — and it prints the
`nm` command that proves placement is link-time and that the shipped compiler
already links from ten translation units. Every runtime file except el_runtime.c
is deliberately uncapped, because that is where code is supposed to go.

Proven with negative controls, per lang/AGENTS.md step 5 — each shown FAILING:
  * +1 line to el_runtime.c                  -> FAIL (20528/20527)
  * +1 engram fn, net-zero lines             -> FAIL (280/279)
  * a new unaccounted lang/runtime/*.c       -> FAIL
  * engram_store.c removed from install.sh   -> FAIL, names the missing file
  * el_runtime.c truncated to 20,000 lines   -> PASS + "lower max_lines to 20000"
  * baseline, tree unmodified                -> OK, and both guards green

el_runtime.c is byte-identical after the controls; this commit changes zero
lines of it.

.gitea/workflows/ci-dev.yaml

@@ -19,6 +19,16 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      # Guards must run from the REPO ROOT — override the job's
+      # defaults.run.working-directory: lang
+      - name: Guard - single canonical runtime source
+        working-directory: ${{ github.workspace }}
+        run: bash scripts/check-single-runtime.sh
+
+      - name: Guard - el_runtime.c growth budget
+        working-directory: ${{ github.workspace }}
+        run: bash scripts/check-runtime-growth.sh
+
       - name: Install build dependencies
         run: |
           apt-get update -qq
@@ -41,7 +51,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elc-gen2.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/platform/elc
           chmod +x dist/platform/elc
@@ -56,7 +66,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elb.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/bin/elb
           chmod +x dist/bin/elb
@@ -87,14 +97,20 @@ jobs:
           bash tests/html_sanitizer/run.sh
 
       # Native El test suites (elc --test, compile-link-run)
-      # el_runtime.c is precompiled to .o once and reused by all 8 modules.
-      - name: Precompile el_runtime.o
+      # The runtime is MULTI-FILE (see lang/runtime/SOURCES). Every .c is compiled
+      # once into /tmp/libel.a and reused by all 8 test modules — compile-once,
+      # link-many, as prescribed in DESIGN.md. Linking el_runtime.c alone fails
+      # at `ld`: it calls into all six engram sibling TUs.
+      - name: Precompile runtime into libel.a
         run: |
           set -euo pipefail
           RUNTIME="$(pwd)/runtime"
-          gcc -O2 -c -I "$RUNTIME" "$RUNTIME/el_runtime.c" \
-            -o /tmp/el_runtime.o
-          echo "el_runtime.o compiled"
+          rm -rf /tmp/elrt && mkdir -p /tmp/elrt
+          for src in $(../scripts/el-runtime-sources.sh --check "$RUNTIME"); do
+            gcc -O2 -c -I "$RUNTIME" "$src" -o "/tmp/elrt/$(basename "${src%.c}").o"
+          done
+          ar rcs /tmp/libel.a /tmp/elrt/*.o
+          echo "libel.a built from $(ls /tmp/elrt/*.o | wc -l) translation units"
 
       - name: Run tests - native (core)
         run: |
@@ -102,7 +118,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_core.el > /tmp/el_native_core.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_core.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_core.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_core
           /tmp/el_native_core
 
@@ -112,7 +128,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_text.el > /tmp/el_native_text.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_text.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_text.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_text
           /tmp/el_native_text
 
@@ -122,7 +138,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_string.el > /tmp/el_native_string.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_string.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_string.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_string
           /tmp/el_native_string
 
@@ -132,7 +148,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_math.el > /tmp/el_native_math.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_math.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_math.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_math
           /tmp/el_native_math
 
@@ -142,7 +158,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_state.el > /tmp/el_native_state.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_state.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_state.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_state
           /tmp/el_native_state
 
@@ -152,7 +168,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_time.el > /tmp/el_native_time.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_time.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_time.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_time
           /tmp/el_native_time
 
@@ -162,7 +178,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_json.el > /tmp/el_native_json.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_json.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_json.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_json
           /tmp/el_native_json
 
@@ -172,7 +188,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_env.el > /tmp/el_native_env.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_env.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_env.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_env
           /tmp/el_native_env
 
@@ -182,7 +198,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_fs.el > /tmp/el_native_fs.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_fs.c /tmp/el_runtime.o \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_fs.c /tmp/libel.a \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_fs
           /tmp/el_native_fs
 
@@ -306,8 +322,9 @@ jobs:
           FROM ${BASE}
           COPY dist/platform/elc                 /opt/el/dist/platform/elc
           COPY dist/bin/elb                       /opt/el/dist/bin/elb
-          COPY runtime/el_runtime.c  /opt/el/runtime/el_runtime.c
-          COPY runtime/el_runtime.h  /opt/el/runtime/el_runtime.h
+          # Whole runtime link set — el_runtime.c alone does not link (it calls
+          # into the six engram sibling TUs). See lang/runtime/SOURCES.
+          COPY runtime/ /opt/el/runtime/
           COPY runtime/el_runtime.js /opt/el/runtime/el_runtime.js
           RUN chmod +x /opt/el/dist/platform/elc /opt/el/dist/bin/elb
           EOF

.gitea/workflows/ci-stage.yaml

@@ -29,6 +29,16 @@ jobs:
           fi
           echo "Source branch check passed: ${SOURCE} -> stage"
 
+      # Guards must run from the REPO ROOT — override the job's
+      # defaults.run.working-directory: lang
+      - name: Guard - single canonical runtime source
+        working-directory: ${{ github.workspace }}
+        run: bash scripts/check-single-runtime.sh
+
+      - name: Guard - el_runtime.c growth budget
+        working-directory: ${{ github.workspace }}
+        run: bash scripts/check-runtime-growth.sh
+
       - name: Install build dependencies
         run: |
           apt-get update -qq
@@ -48,7 +58,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elc-gen2.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/platform/elc
           chmod +x dist/platform/elc
@@ -86,7 +96,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_core.el > /tmp/el_native_core.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_core.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_core.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_core
           /tmp/el_native_core
 
@@ -96,7 +106,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_text.el > /tmp/el_native_text.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_text.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_text.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_text
           /tmp/el_native_text
 
@@ -106,7 +116,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_string.el > /tmp/el_native_string.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_string.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_string.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_string
           /tmp/el_native_string
 
@@ -116,7 +126,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_math.el > /tmp/el_native_math.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_math.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_math.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_math
           /tmp/el_native_math
 
@@ -126,7 +136,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_state.el > /tmp/el_native_state.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_state.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_state.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_state
           /tmp/el_native_state
 
@@ -136,7 +146,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_time.el > /tmp/el_native_time.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_time.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_time.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_time
           /tmp/el_native_time
 
@@ -146,7 +156,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_json.el > /tmp/el_native_json.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_json.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_json.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_json
           /tmp/el_native_json
 
@@ -156,7 +166,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_env.el > /tmp/el_native_env.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_env.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_env.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_env
           /tmp/el_native_env
 
@@ -166,7 +176,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_fs.el > /tmp/el_native_fs.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_fs.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_fs.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_fs
           /tmp/el_native_fs
 
@@ -178,7 +188,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elb.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/bin/elb
           chmod +x dist/bin/elb
@@ -290,8 +300,9 @@ jobs:
           FROM ${BASE}
           COPY dist/platform/elc                 /opt/el/dist/platform/elc
           COPY dist/bin/elb                       /opt/el/dist/bin/elb
-          COPY runtime/el_runtime.c  /opt/el/runtime/el_runtime.c
-          COPY runtime/el_runtime.h  /opt/el/runtime/el_runtime.h
+          # Whole runtime link set — el_runtime.c alone does not link (it calls
+          # into the six engram sibling TUs). See lang/runtime/SOURCES.
+          COPY runtime/ /opt/el/runtime/
           COPY runtime/el_runtime.js /opt/el/runtime/el_runtime.js
           RUN chmod +x /opt/el/dist/platform/elc /opt/el/dist/bin/elb
           EOF

.gitea/workflows/sdk-release.yaml

@@ -29,6 +29,16 @@ jobs:
           fi
           echo "Source branch check passed: ${SOURCE} -> main"
 
+      # Guards must run from the REPO ROOT — override the job's
+      # defaults.run.working-directory: lang
+      - name: Guard - single canonical runtime source
+        working-directory: ${{ github.workspace }}
+        run: bash scripts/check-single-runtime.sh
+
+      - name: Guard - el_runtime.c growth budget
+        working-directory: ${{ github.workspace }}
+        run: bash scripts/check-runtime-growth.sh
+
       - name: Install build dependencies
         run: |
           apt-get update -qq
@@ -49,7 +59,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elc-gen2.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/platform/elc
           chmod +x dist/platform/elc
@@ -64,7 +74,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elb.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/bin/elb
           chmod +x dist/bin/elb
@@ -123,7 +133,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_core.el > /tmp/el_native_core.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_core.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_core.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_core
           /tmp/el_native_core
 
@@ -133,7 +143,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_text.el > /tmp/el_native_text.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_text.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_text.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_text
           /tmp/el_native_text
 
@@ -143,7 +153,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_string.el > /tmp/el_native_string.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_string.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_string.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_string
           /tmp/el_native_string
 
@@ -153,7 +163,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_math.el > /tmp/el_native_math.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_math.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_math.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_math
           /tmp/el_native_math
 
@@ -163,7 +173,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_state.el > /tmp/el_native_state.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_state.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_state.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_state
           /tmp/el_native_state
 
@@ -173,7 +183,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_time.el > /tmp/el_native_time.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_time.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_time.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_time
           /tmp/el_native_time
 
@@ -183,7 +193,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_json.el > /tmp/el_native_json.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_json.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_json.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_json
           /tmp/el_native_json
 
@@ -193,7 +203,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_env.el > /tmp/el_native_env.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_env.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_env.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_env
           /tmp/el_native_env
 
@@ -203,7 +213,7 @@ jobs:
           ELC="$(pwd)/dist/platform/elc"
           RUNTIME="$(pwd)/runtime"
           "$ELC" --test tests/native/test_fs.el > /tmp/el_native_fs.c
-          gcc -O2 -I "$RUNTIME" /tmp/el_native_fs.c "$RUNTIME/el_runtime.c" \
+          gcc -O2 -I "$RUNTIME" /tmp/el_native_fs.c $(../scripts/el-runtime-sources.sh "$RUNTIME") \
             -lcurl -lssl -lcrypto -lpthread -lm -o /tmp/el_native_fs
           /tmp/el_native_fs
 
@@ -216,10 +226,17 @@ jobs:
           cp lang/dist/platform/elc          dist/sdk/bin/elc
           cp lang/dist/bin/elb               dist/sdk/bin/elb
           cp lang/dist/bin/epm               dist/sdk/bin/epm
-          cp lang/runtime/el_runtime.c  dist/sdk/runtime/
-          cp lang/runtime/el_runtime.h  dist/sdk/runtime/
-          cp lang/runtime/engram_store.c dist/sdk/runtime/
-          cp lang/runtime/engram_store.h dist/sdk/runtime/
+          # Ship the WHOLE runtime link set, not el_runtime.c alone. el_runtime.c
+          # #includes six engram headers and calls into all six sibling .c files,
+          # so an SDK carrying only el_runtime.c{,.h} + engram_store.c{,.h} cannot
+          # link — downstream `ld` fails on engram_ground_json, eg_find_relation,
+          # cog_assert_two_axis and friends. lang/runtime/SOURCES is the source of
+          # truth; --check makes a missing file fail the release loudly.
+          for f in $(scripts/el-runtime-sources.sh --check) \
+                   $(scripts/el-runtime-sources.sh --headers --check); do
+            cp "lang/runtime/${f}" dist/sdk/runtime/
+          done
+          cp lang/runtime/SOURCES            dist/sdk/runtime/
           cp lang/runtime/*.el               dist/sdk/runtime/
           tar -czf dist/el-sdk-latest.tar.gz -C dist/sdk .
           echo "SDK tarball bundled: dist/el-sdk-latest.tar.gz"
@@ -274,12 +291,16 @@ jobs:
               "${GITEA_API}/repos/${REPO}/releases/${RELEASE_ID}/assets"
           }
 
-          # Per-file assets (downstream CI needs these individually)
+          # Per-file assets (downstream CI needs these individually).
+          # lang/install.sh downloads every one of these by name — the list is
+          # lang/runtime/SOURCES. Shipping el_runtime.c alone produced a lib/
+          # that could not link; that is the bug this loop closes.
           upload_asset lang/dist/platform/elc                elc
-          upload_asset lang/runtime/el_runtime.c el_runtime.c
-          upload_asset lang/runtime/el_runtime.h el_runtime.h
-          upload_asset lang/runtime/engram_store.c engram_store.c
-          upload_asset lang/runtime/engram_store.h engram_store.h
+          for f in $(scripts/el-runtime-sources.sh --check) \
+                   $(scripts/el-runtime-sources.sh --headers --check); do
+            upload_asset "lang/runtime/${f}" "${f}"
+          done
+          upload_asset lang/runtime/SOURCES SOURCES
 
           # SDK bundle and installer binary
           upload_asset dist/el-sdk-latest.tar.gz             el-sdk-latest.tar.gz
@@ -350,6 +371,26 @@ jobs:
             --version="${VERSION}" \
             --source=runtime/el_runtime.js
 
+          # el-runtime-src — the COMPLETE runtime link set as one tarball.
+          #
+          # The el-runtime-c / el-runtime-h packages above are single files and are
+          # kept for backward compatibility with consumers that already pull them,
+          # but they are NOT sufficient to link: el_runtime.c calls into six engram
+          # sibling translation units. New consumers should pull el-runtime-src and
+          # link everything named in its SOURCES file.
+          tar -czf /tmp/el-runtime-src.tar.gz \
+            -C runtime SOURCES \
+            $(../scripts/el-runtime-sources.sh --check) \
+            $(../scripts/el-runtime-sources.sh --headers --check)
+
+          gcloud artifacts generic upload \
+            --repository=foundation-prod \
+            --location=us-central1 \
+            --project=neuron-785695 \
+            --package=el-runtime-src \
+            --version="${VERSION}" \
+            --source=/tmp/el-runtime-src.tar.gz
+
           echo "Published El SDK version=${VERSION} to foundation-prod"
           # Keep key alive for the ci-base rebuild step below
           # (deleted in that step after docker push)
@@ -386,8 +427,9 @@ jobs:
           FROM ${BASE}
           COPY dist/platform/elc                 /opt/el/dist/platform/elc
           COPY dist/bin/elb                       /opt/el/dist/bin/elb
-          COPY runtime/el_runtime.c  /opt/el/runtime/el_runtime.c
-          COPY runtime/el_runtime.h  /opt/el/runtime/el_runtime.h
+          # Whole runtime link set — el_runtime.c alone does not link (it calls
+          # into the six engram sibling TUs). See lang/runtime/SOURCES.
+          COPY runtime/ /opt/el/runtime/
           COPY runtime/el_runtime.js /opt/el/runtime/el_runtime.js
           RUN chmod +x /opt/el/dist/platform/elc /opt/el/dist/bin/elb
           EOF

.githooks/pre-commit

@@ -9,13 +9,52 @@ LANG_DIR="$ROOT/lang"
 RUNTIME="$LANG_DIR/runtime"
 ELC="$LANG_DIR/dist/platform/elc"
 
+# Runtime guards — catch drift and growth before they are committed, not in CI.
+#   check-single-runtime.sh : el_runtime.c must not be FORKED (a lagging copy
+#                             shipped to prod and dropped learned hebb edges).
+#   check-runtime-growth.sh : el_runtime.c must not GROW (it is a 2026-05-03
+#                             build shim that was never retired; see BUDGET).
+echo "→ Runtime guards..."
+bash "$ROOT/scripts/check-single-runtime.sh"
+bash "$ROOT/scripts/check-runtime-growth.sh"
+
 # If elc isn't built yet, skip with a warning rather than blocking
 if [ ! -x "$ELC" ]; then
   echo "⚠  elc not found at lang/dist/platform/elc — skipping pre-commit tests"
-  echo "   Build it first: cd lang && gcc -O2 -I runtime dist/elc-bootstrap.c runtime/el_runtime.c -lcurl -lpthread -o dist/elc-gen2 && ./dist/elc-gen2 el-compiler/src/compiler.el > /tmp/elc.c && gcc -O2 -I runtime /tmp/elc.c runtime/el_runtime.c -lcurl -lpthread -o dist/platform/elc"
+  echo "   Build it first: see 'Rebuilding the Compiler' in lang/AGENTS.md"
+  echo "   (link \$($ROOT/scripts/el-runtime-sources.sh $RUNTIME) — NOT el_runtime.c alone)"
   exit 0
 fi
 
+# The runtime is MULTI-FILE (lang/runtime/SOURCES). This hook used to link
+# "$RUNTIME/el_runtime.c" alone with stderr sent to /dev/null — so once
+# el_runtime.c started calling into the engram siblings, every native test
+# reported as FAILED with the real `ld` error invisible. Build the whole set
+# once into an archive, then link each test against it.
+
+# macOS: Homebrew openssl@3 is not on the default include/lib search path, so
+# without these the link fails on -lssl/-lcrypto. Empty on Linux/CI.
+SSL_INC=""
+SSL_LIB=""
+if command -v brew >/dev/null 2>&1 && OSSL="$(brew --prefix openssl@3 2>/dev/null)" && [ -n "$OSSL" ]; then
+  SSL_INC="-I$OSSL/include"
+  SSL_LIB="-L$OSSL/lib"
+fi
+
+echo "→ Building runtime (compile-once, link-many)..."
+HOOK_LIB="/tmp/el_hook_libel.a"
+HOOK_OBJ="/tmp/el_hook_obj"
+rm -rf "$HOOK_OBJ" && mkdir -p "$HOOK_OBJ"
+if ! for src in $("$ROOT/scripts/el-runtime-sources.sh" --check "$RUNTIME"); do
+       gcc -O2 -c -I "$RUNTIME" $SSL_INC "$src" -o "$HOOK_OBJ/$(basename "${src%.c}").o" || exit 1
+     done; then
+  echo "✗ Pre-commit failed: the runtime does not compile."
+  echo "  Re-run without 2>/dev/null to see the error:"
+  echo "    gcc -O2 -c -I $RUNTIME \$($ROOT/scripts/el-runtime-sources.sh $RUNTIME)"
+  exit 1
+fi
+ar rcs "$HOOK_LIB" "$HOOK_OBJ"/*.o
+
 echo "→ Running El native tests..."
 PASS=0
 FAIL=0
@@ -27,8 +66,8 @@ for test_file in "$LANG_DIR"/tests/native/test_*.el; do
   tmp_bin="/tmp/el_hook_${name}"
 
   if "$ELC" --test "$test_file" > "$tmp_c" 2>/dev/null \
-     && gcc -O2 -I "$RUNTIME" "$tmp_c" "$RUNTIME/el_runtime.c" \
-          -lcurl -lpthread -lm -o "$tmp_bin" 2>/dev/null \
+     && gcc -O2 -I "$RUNTIME" $SSL_INC $SSL_LIB "$tmp_c" "$HOOK_LIB" \
+          -lcurl -lssl -lcrypto -lpthread -lm -o "$tmp_bin" 2>/dev/null \
      && "$tmp_bin" 2>/dev/null; then
     PASS=$((PASS + 1))
   else

AGENTS.md

@@ -199,21 +199,35 @@ wrong, say so with a measurement rather than editing it.
 
 All build/test commands run from `lang/` unless noted. Grounded in `.gitea/workflows/sdk-release.yaml`, `lang/install.sh`, and `lang/AGENTS.md`.
 
+> ### The runtime is MULTI-FILE — never link `el_runtime.c` alone
+>
+> `lang/runtime/el_runtime.c` `#include`s six engram headers and makes hard cross-TU calls into all six sibling `.c` files. **Linking it by itself fails at `ld`** (undefined `engram_ground_json`, `engram_activate_inner`, `eg_find_relation`, `cog_assert_two_axis`, …). The canonical link set lives in exactly one place — **`lang/runtime/SOURCES`** — and is printed by `scripts/el-runtime-sources.sh`:
+>
+> ```bash
+> scripts/el-runtime-sources.sh lang/runtime   # ten .c files, in link order
+> ```
+>
+> Use `$(scripts/el-runtime-sources.sh <runtime-dir>)` in every link line. Do not spell the list out longhand — it was written out in ~8 places, every copy drifted, and that is why the one-file link line below shipped broken for months. *(Corrected 2026-08-16.)*
+
 **Self-host the compiler** (seed binary → gen2 elc):
 ```bash
 cd lang
 dist/platform/elc-linux-amd64 elc-cli.el > dist/elc-gen2.c   # seed is the committed linux-amd64 binary
-gcc -O2 -I el-compiler/runtime dist/elc-gen2.c \
-    el-compiler/runtime/el_runtime.c \
+gcc -O2 -I runtime dist/elc-gen2.c \
+    $(../scripts/el-runtime-sources.sh runtime) \
     -lcurl -lssl -lcrypto -lpthread -lm \
     -o dist/platform/elc
 ```
-On macOS/arm64 the canonical local binary is `dist/platform/elc`; verify self-hosting by recompiling and `diff`ing the emitted `.c` (see `lang/AGENTS.md`). Note: `lang/AGENTS.md` says `el_seed.c` supersedes `el_runtime.c`, but the release workflow still links `el_runtime.c`/`.h` — treat `el_runtime.c` as the published runtime; reconcile which is canonical **(verify)**.
+On macOS/arm64 the canonical local binary is `dist/platform/elc`; verify self-hosting by recompiling and `diff`ing the emitted `.c` (see `lang/AGENTS.md`).
+
+*(Corrected 2026-08-16: this recipe compiled `el-compiler/runtime/el_runtime.c`. That path is a **lagging fork** — the "DO NOT EDIT" list at the top of this file names it as such. Building the canonical compiler from a known-stale fork was a live defect. It now uses `lang/runtime/`, the canonical source.)*
+
+**Which runtime file is canonical — resolved.** *(This note previously read "`lang/AGENTS.md` says `el_seed.c` supersedes `el_runtime.c`, but the release workflow still links `el_runtime.c`/`.h` — reconcile which is canonical **(verify)**." It is now reconciled.)* **Neither supersedes the other; both ship, together with eight more.** `el_runtime.c` was created on 2026-05-03 as an explicitly temporary build shim — deleted that afternoon, restored 25 minutes later "UNTIL the compiler is updated to emit `#include el_seed.h`" — and the `until` never happened, so it grew to 20.5k lines. The end state remains a seed-only boundary (`elc` emitting `#include "el_seed.h"`, `elb` dropping its hardcoded runtime path); until that lands, **the canonical unit is the set in `lang/runtime/SOURCES`, not any one file.**
 
 **Build `elb`** (build coordinator, the `.NET`-style incremental linker — compiles each module independently, no monolithic blobs):
 ```bash
 dist/platform/elc elb.el > dist/elb.c
-gcc -O2 -I el-compiler/runtime dist/elb.c el-compiler/runtime/el_runtime.c \
+gcc -O2 -I runtime dist/elb.c $(../scripts/el-runtime-sources.sh runtime) \
     -lcurl -lssl -lcrypto -lpthread -lm -o dist/bin/elb
 ```
 `epm` and `el-install` are then built via `elb --clean --elc=… --runtime=… --out=…`.
@@ -221,10 +235,16 @@ gcc -O2 -I el-compiler/runtime dist/elb.c el-compiler/runtime/el_runtime.c \
 **Compile + run an El program:**
 ```bash
 elc src/app.el > dist/app.c
-cc -std=c11 -O2 -I <lib>/el_runtime -o dist/app dist/app.c <lib>/el_runtime.c -lcurl -lpthread
+cc -std=c11 -O2 -I <lib> -o dist/app dist/app.c \
+   <lib>/el_runtime.c <lib>/el_seed.c \
+   <lib>/engram_store.c <lib>/engram_vindex.c <lib>/engram_geometry.c \
+   <lib>/engram_reason.c <lib>/engram_verify.c <lib>/engram_cognition.c \
+   <lib>/eg_cosine_batch.c <lib>/eg_cosine_batch_strategy_cpu.c \
+   -lcurl -lssl -lcrypto -lpthread -lm
 ```
+(Inside this repo, replace the file list with `$(scripts/el-runtime-sources.sh lang/runtime)`. `install.sh` installs all of these into `<lib>`.)
 
-**Tests** — shell suites `bash tests/{text,calendar,time,html_sanitizer}/run.sh` (with `ELC=$(pwd)/dist/platform/elc EL_HOME=$(pwd)`), plus native suites via `elc --test tests/native/test_*.el` (core, text, string, math, state, time, json, env, fs) compiled and run against `el_runtime.c`.
+**Tests** — shell suites `bash tests/{text,calendar,time,html_sanitizer}/run.sh` (with `ELC=$(pwd)/dist/platform/elc EL_HOME=$(pwd)`), plus native suites via `elc --test tests/native/test_*.el` (core, text, string, math, state, time, json, env, fs) compiled and run against the full runtime set.
 
 **Publishing — how downstream gets the SDK.** On push to `main`, `sdk-release.yaml`:
 1. Publishes a Gitea `latest` release with per-file assets `elc`, `el_runtime.c`, `el_runtime.h`, the SDK tarball, and `el-install`.

DESIGN.md

@@ -548,9 +548,13 @@ before `main` does anything. That is the dividend of discovery-precedes-executio
 
 ```
 # once, ever (or when the runtime/framework changes):
-cc -c el_runtime.c        -o el_runtime.o
-elc eltest.el > eltest.c && cc -c eltest.c -o eltest.o
-ar rcs libeltest.a el_runtime.o eltest.o
+# The runtime is MULTI-FILE — compile every .c named in lang/runtime/SOURCES.
+# Linking el_runtime.c alone fails: it calls into the six engram sibling TUs.
+for src in $(scripts/el-runtime-sources.sh lang/runtime); do
+  cc -c "$src" -o "obj/$(basename "${src%.c}").o"
+done
+elc eltest.el > eltest.c && cc -c eltest.c -o obj/eltest.o
+ar rcs libeltest.a obj/*.o
 
 # per suite:
 elc --test foo_test.el > foo_test.c     # registry + bodies only

lang/AGENTS.md

@@ -77,14 +77,30 @@ This is where almost all work belongs. El programs are source files that get com
 
 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 runtime is native El (`runtime/*.el`) over a C OS-boundary. **Status (verified 2026-08-15):** the migration to a seed-only boundary is *in progress, not done*. Two files exist:
-- `runtime/el_runtime.c` (~860 KB) — **LIVE**. Holds the engram store (`EngramStore engram_global`) plus the `http_*`/`json_*`/`state_*`/`engram_*` impls. It is the authoritative single-file link target for the compiler, and `tools/install.sh` compiles it into `libel.a`. This is where a new C builtin's *implementation* must currently live to be linkable.
-- `runtime/el_seed.c` — the intended hand-maintained `__`-prefixed seed (thin wrappers over the above). It is compiled alongside `el_runtime.c` by `tools/install.sh`, but does **not** compile standalone yet (see the build-path caveat under "Rebuilding the Compiler").
+The runtime is native El (`runtime/*.el`) over a C OS-boundary. **Status (verified 2026-08-16):** the migration to a seed-only boundary is *in progress, not done*.
+
+**The runtime is MULTI-FILE. There is no single-file link target and there has not been one for months.** The canonical link set is listed once, in **`runtime/SOURCES`**, and printed by `scripts/el-runtime-sources.sh`. It currently holds ten translation units: `el_runtime.c`, `el_seed.c`, the six `engram_*.c` concern files, and `eg_cosine_batch{,_strategy_cpu}.c`.
+
+- `runtime/el_runtime.c` (~940 KB, 20.5k lines) — **LIVE, and oversized.** It began life on 2026-05-03 as a temporary build shim: it was deleted that afternoon ("runtime is 100% native El") and restored 25 minutes later, explicitly "UNTIL the compiler is updated to emit `#include el_seed.h`". That `until` never arrived, and in the 3.5 months since, the file doubled. **It is not a volatility unit — it is a dumping ground.** ~47.5% of it is engram code that belongs in the six sibling files that already exist. Do not add to it. See "Where a new C builtin goes" below.
+- `runtime/el_seed.c` — the intended hand-maintained `__`-prefixed seed (thin wrappers over the above).
+- `runtime/engram_{store,vindex,geometry,reason,verify,cognition}.c` — the engram concerns, each with its own header. `el_runtime.c` `#include`s all six headers and makes hard cross-TU calls into all six.
+
+> **Linking `el_runtime.c` alone does not work and has not for months.** It fails at `ld` with undefined symbols (`engram_ground_json`, `engram_activate_inner`, `eg_find_relation`, `cog_assert_two_axis`, …). Any recipe, script, or CI step that names `el_runtime.c` by itself is stale — replace it with `$(scripts/el-runtime-sources.sh lang/runtime)`.
 
 **Only edit these when you genuinely need OS-level access** (raw sockets, GPU calls, new libcurl features, a new engram store op). For everything else, write El.
 
+#### Where a new C builtin goes
+
+**Put it in the `.c` that owns the concern — NOT in `el_runtime.c`.**
+
+*Placement is a link-time concern. The compiler cannot tell which `.c` a symbol came from, and never could.* `builtin_arity` in `el-compiler/src/codegen.el` maps NAME → ARITY INT and nothing else (~413 entries); the El name is emitted as the exact C symbol and resolved by `ld`. Proof, if you want it: `nm lang/dist/platform/elc` on the *shipped* compiler shows `T _engram_geo_reify_index_new` (defined in `engram_geometry.c`), `T _vindex_insert` (`engram_vindex.c`), `T _engram_think` (`engram_cognition.c`), `T _engram_reason_abduce` (`engram_reason.c`). **The shipped compiler is already linked from ten translation units.** A builtin defined in a sibling `.c` is exactly as linkable as one defined in `el_runtime.c`.
+
+Choose the file by concern: engram store ops → `engram_store.c`; index → `engram_vindex.c`; geometry/priming → `engram_geometry.c`; reasoning → `engram_reason.c`; grounding/consistency → `engram_verify.c`; think/stance → `engram_cognition.c`. **If no existing file owns it, create one** — add the `.c` to `runtime/SOURCES` (one line) and every build path picks it up. For a builtin that belongs to a downstream program rather than the runtime, declare `c_source "path/to/file.c"` in that program's `manifest.el`; `elb` already links it (`parse_manifest_c_sources`, `lang/elb.el:82`).
+
+> **`el_runtime.c` is on a ratchet and will reject your commit.** `runtime/BUDGET` caps it at its current line count *with no headroom*, and separately caps the number of `engram_*`/`eg_*`/`cog_*` function definitions in it. `scripts/check-runtime-growth.sh` enforces both in CI and in `.githooks/pre-commit`. **The numbers may only ever go down — do not raise them.** Every other runtime file is deliberately uncapped, because that is where the code is supposed to go. When you move code *out*, lower the numbers in the same commit; the guard tells you the new values.
+
 When you add a C builtin (verbatim-emit recipe — the El name is emitted as the exact C symbol; `builtin_arity` is an arity guard only, not a dispatch table):
-1. Implement the C function in `el_runtime.c` (and declare it in `el_runtime.h`).
+1. Implement the C function in the **concern-owning `.c`** (and declare it in that file's `.h`). Add the file to `runtime/SOURCES` if it is new. Only put it in `el_runtime.c` if it is genuinely EL core (val/str/map/list/arena) — that is ~8% of what is in there today.
 2. Add a `__`-prefixed thin wrapper in `el_seed.c` and declare it in `el_seed.h`.
 3. Add the name to `builtin_arity` in `el-compiler/src/codegen.el` — add **both** the plain and `__`-prefixed spellings.
 4. Rebuild the elc binary (see below) and confirm the self-host fixpoint is byte-identical.
@@ -125,7 +141,9 @@ diff elc-new.c elc-verify.c   # must be identical
 mv dist/platform/elc-new dist/platform/elc
 ```
 
-> **Build-path caveat (verified 2026-08-15).** `el_seed.c` is the intended hand-maintained OS-boundary seed, but it does **not** compile standalone under modern clang: it wraps ~16 unprefixed `el_runtime.c` symbols (`http_serve`, `json_*`, `state_*`, `http_response`) without prototypes, and clang treats implicit declarations as errors (C99+). The productionised install (`tools/install.sh`) builds `libel.a` from **both** `el_seed.o` + `el_runtime.o` together, which is why linking succeeds there. To make `el_seed.c` build on its own, add prototypes for those symbols (or `#include "el_runtime.h"`, reconciling the `__http_serve` return-type mismatch first). Until then, `el_runtime.c` is the authoritative single-file link target for the compiler.
+> **Build-path caveat (verified 2026-08-15).** `el_seed.c` is the intended hand-maintained OS-boundary seed, but it does **not** compile standalone under modern clang: it wraps ~16 unprefixed `el_runtime.c` symbols (`http_serve`, `json_*`, `state_*`, `http_response`) without prototypes, and clang treats implicit declarations as errors (C99+). The productionised install (`tools/install.sh`) builds `libel.a` from **both** `el_seed.o` + `el_runtime.o` together, which is why linking succeeds there. To make `el_seed.c` build on its own, add prototypes for those symbols (or `#include "el_runtime.h"`, reconciling the `__http_serve` return-type mismatch first).
+>
+> **There is no single-file link target.** *(Corrected 2026-08-16 — this paragraph previously ended "`el_runtime.c` is the authoritative single-file link target for the compiler". Measured: that is false. Linking `elc-new.c` against `runtime/el_runtime.c` alone fails at `ld` with undefined `engram_ground_json`, `engram_activate_inner`, `eg_find_relation`, `cog_assert_two_axis`, and others, because `el_runtime.c` `#include`s six engram headers and calls into all six sibling `.c` files.)* Link the set in `runtime/SOURCES` via `$(../scripts/el-runtime-sources.sh runtime)`.
 
 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.
 

lang/install.sh

@@ -49,21 +49,47 @@ download() {
 TMP_DIR="$(mktemp -d)"
 trap 'rm -rf "${TMP_DIR}"' EXIT
 
-download "${RELEASE_BASE}/elc"          "${TMP_DIR}/elc"
-download "${RELEASE_BASE}/el_runtime.c" "${TMP_DIR}/el_runtime.c"
-download "${RELEASE_BASE}/el_runtime.h" "${TMP_DIR}/el_runtime.h"
+# The runtime is MULTI-FILE. el_runtime.c #includes six engram headers and makes
+# hard cross-TU calls into all six sibling .c files, so installing el_runtime.c
+# alone produces a lib/ that CANNOT LINK — `ld` fails with undefined
+# engram_ground_json / engram_activate_inner / eg_find_relation / cog_assert_two_axis.
+# This list mirrors lang/runtime/SOURCES (the in-repo source of truth); keep them
+# in step. install.sh is standalone by design — it runs on machines with no repo
+# checkout — so it cannot call scripts/el-runtime-sources.sh.
+RUNTIME_SOURCES=(
+    el_runtime.c el_seed.c
+    engram_store.c engram_vindex.c engram_geometry.c
+    engram_reason.c engram_verify.c engram_cognition.c
+    eg_cosine_batch.c eg_cosine_batch_strategy_cpu.c
+)
+RUNTIME_HEADERS=(
+    el_runtime.h el_seed.h
+    engram_store.h engram_vindex.h engram_geometry.h
+    engram_reason.h engram_verify.h engram_cognition.h
+    eg_cosine_batch.h eg_cosine_batch_strategy.h
+)
+
+download "${RELEASE_BASE}/elc" "${TMP_DIR}/elc"
+for f in "${RUNTIME_SOURCES[@]}" "${RUNTIME_HEADERS[@]}"; do
+    download "${RELEASE_BASE}/${f}" "${TMP_DIR}/${f}"
+done
 
 # Install
-install -m 755 "${TMP_DIR}/elc"          "${BIN_DIR}/elc"
-install -m 644 "${TMP_DIR}/el_runtime.c" "${LIB_DIR}/el_runtime.c"
-install -m 644 "${TMP_DIR}/el_runtime.h" "${LIB_DIR}/el_runtime.h"
+install -m 755 "${TMP_DIR}/elc" "${BIN_DIR}/elc"
+for f in "${RUNTIME_SOURCES[@]}" "${RUNTIME_HEADERS[@]}"; do
+    install -m 644 "${TMP_DIR}/${f}" "${LIB_DIR}/${f}"
+done
+
+# Record the link set so downstream Makefiles can read it instead of hardcoding.
+printf '%s\n' "${RUNTIME_SOURCES[@]}" > "${TMP_DIR}/SOURCES"
+install -m 644 "${TMP_DIR}/SOURCES" "${LIB_DIR}/SOURCES"
 
 echo
 echo "==> El SDK installed successfully"
 echo
 echo "    elc binary : ${BIN_DIR}/elc"
-echo "    runtime    : ${LIB_DIR}/el_runtime.c"
-echo "    header     : ${LIB_DIR}/el_runtime.h"
+echo "    runtime    : ${LIB_DIR}/ (${#RUNTIME_SOURCES[@]} .c files, ${#RUNTIME_HEADERS[@]} headers)"
+echo "    link set   : ${LIB_DIR}/SOURCES"
 echo
 echo "Add the following to your Makefile to build El programs:"
 echo
@@ -71,10 +97,14 @@ echo "    EL_LIB := ${LIB_DIR}"
 echo "    ELC    := elc"
 echo "    CC     := cc"
 echo "    CFLAGS := -std=c11 -O2 -I\$(EL_LIB)"
+echo "    LDLIBS := -lcurl -lssl -lcrypto -lpthread -lm"
+echo
+echo "    # The runtime is multi-file — link the whole set, not el_runtime.c alone."
+echo "    EL_RUNTIME := \$(addprefix \$(EL_LIB)/,\$(shell cat \$(EL_LIB)/SOURCES))"
 echo
 echo "    dist/myapp.c: src/myapp.el"
 echo "    \t\$(ELC) src/myapp.el > dist/myapp.c"
 echo
 echo "    dist/myapp: dist/myapp.c"
-echo "    \t\$(CC) \$(CFLAGS) -o dist/myapp dist/myapp.c \$(EL_LIB)/el_runtime.c -lcurl -lpthread"
+echo "    \t\$(CC) \$(CFLAGS) -o dist/myapp dist/myapp.c \$(EL_RUNTIME) \$(LDLIBS)"
 echo

lang/runtime/BUDGET

@@ -0,0 +1,39 @@
+# BUDGET — a RATCHET on lang/runtime/el_runtime.c. Enforced by
+# scripts/check-runtime-growth.sh. These numbers may only ever go DOWN.
+#
+# WHY THIS FILE EXISTS
+# --------------------
+# scripts/check-single-runtime.sh guards against el_runtime.c being COPIED.
+# Nothing guarded against it GROWING. It grew from 10,607 lines to 20,527 —
+# 94% — in 3.5 months, while under an explicit commit-message promise that it
+# was a temporary shim about to be deleted.
+#
+# It grew because lang/AGENTS.md told every agent to grow it: it claimed
+# el_runtime.c was "the authoritative single-file link target" and that a new
+# C builtin "must live there to be linkable". That is false — placement is a
+# link-time concern, `builtin_arity` is an arity guard not a dispatch table,
+# and the shipped elc already links from ten translation units. The claim is
+# corrected, and this file is the mechanism that keeps it corrected.
+#
+# THIS IS A RATCHET, NOT A LIMIT
+# ------------------------------
+# The budget is set at the CURRENT size. There is no headroom, deliberately.
+# The file cannot grow by even one line. Any new code goes in the .c that owns
+# the concern — that is the whole point, and every other runtime file is
+# deliberately UNCAPPED.
+#
+# When you move code OUT, lower the number in the same commit. The guard tells
+# you to when you have earned it.
+#
+# FORMAT: <key> <value>   — `#` comments and blank lines ignored.
+
+# Maximum lines in lang/runtime/el_runtime.c.
+# 2026-08-16: 20,527 — the high-water mark, ratcheted from here.
+max_lines 20527
+
+# Maximum top-level engram/eg_/cog_ function definitions in el_runtime.c.
+# ~47.5% of the file is engram code, and engram already owns six dedicated
+# sibling files (engram_{store,vindex,geometry,reason,verify,cognition}.c).
+# Every one of these belongs in one of them. This is the Stage 3 scoreboard.
+# 2026-08-16: 279.
+max_engram_fns 279

lang/runtime/SOURCES

@@ -0,0 +1,52 @@
+# SOURCES — the canonical El runtime link set.
+#
+# THIS FILE IS THE SINGLE SOURCE OF TRUTH for "what do I compile and link to
+# get the El runtime". Every build path — CI, install.sh, the SDK release, the
+# docs, elb, the engram test harnesses — reads it via scripts/el-runtime-sources.sh
+# instead of hardcoding its own list.
+#
+# WHY THIS FILE EXISTS
+# --------------------
+# The runtime has been multi-translation-unit since the engram siblings landed:
+# el_runtime.c #includes engram_{store,vindex,geometry,reason,verify,cognition}.h
+# and makes hard cross-TU calls into all six. Linking el_runtime.c ALONE has been
+# broken since then — `ld` fails with undefined symbols (engram_ground_json,
+# engram_activate_inner, eg_find_relation, cog_assert_two_axis, ...).
+#
+# It stayed broken because the link set was written out longhand in ~8 different
+# places, each of which drifted independently. A list copied 8 times is a list
+# that is wrong in 8 places. It is now written once, here.
+#
+# HOW TO USE IT
+# -------------
+#   scripts/el-runtime-sources.sh                      # bare names, one per line
+#   scripts/el-runtime-sources.sh lang/runtime         # prefixed with a directory
+#   cc ... $(scripts/el-runtime-sources.sh lang/runtime) -lcurl -lssl -lcrypto -lpthread -lm
+#
+# ADDING A FILE
+# -------------
+# Add the .c here and it is picked up by every build path at once. That is the
+# point: a new concern gets its own translation unit and costs one line, instead
+# of being appended to el_runtime.c because appending was the cheaper edit.
+#
+# Order is link order. Blank lines and `#` comments are ignored.
+
+# --- EL core language runtime -------------------------------------------------
+el_runtime.c
+el_seed.c
+
+# --- Engram: store, index, geometry, reasoning, verification, cognition -------
+# These are the six concern-owned translation units el_runtime.c calls into.
+engram_store.c
+engram_vindex.c
+engram_geometry.c
+engram_reason.c
+engram_verify.c
+engram_cognition.c
+
+# --- Vector math: batch cosine + its CPU strategy ----------------------------
+# The ggml strategy (eg_cosine_batch_strategy_ggml.c) is an OPTIONAL swap-in and
+# is deliberately NOT in the default set — it needs ggml headers. Link it in
+# place of the cpu strategy when you have them.
+eg_cosine_batch.c
+eg_cosine_batch_strategy_cpu.c

lang/spec/language.md

@@ -697,12 +697,22 @@ Every compiled program links against:
 - `el_runtime.h` — declaration header
 - `el_runtime.c` — implementation
 
+The runtime is **multi-file**: `el_runtime.c` `#include`s the six `engram_*.h`
+headers and calls into all six sibling translation units, so linking it alone
+fails at `ld`. The canonical link set is `<runtime-dir>/SOURCES`.
+
 Compile command:
 
 ```
-cc -std=c11 -I<runtime-dir> -o <prog> <prog>.c el_runtime.c
+cc -std=c11 -I<runtime-dir> -o <prog> <prog>.c \
+   $(sed 's|^|<runtime-dir>/|' <runtime-dir>/SOURCES) \
+   -lcurl -lssl -lcrypto -lpthread -lm
 ```
 
+Inside this repo, `scripts/el-runtime-sources.sh <runtime-dir>` prints that list
+(it strips comments; the raw `sed` above works against an installed SDK's
+`SOURCES`, which `install.sh` writes comment-free).
+
 ### 13.4 Output Format
 
 ```c

scripts/check-runtime-growth.sh

@@ -0,0 +1,161 @@
+#!/usr/bin/env bash
+# check-runtime-growth.sh — GROWTH guard for lang/runtime/el_runtime.c.
+#
+# Sibling to scripts/check-single-runtime.sh. That one guards against the file
+# being COPIED (a lagging fork shipped to prod and dropped learned hebb edges).
+# Nothing guarded against it GROWING — so it grew from 10,607 to 20,527 lines in
+# 3.5 months, while under an explicit commit-message promise that it was a
+# temporary shim about to be deleted.
+#
+# This enforces the RATCHET in lang/runtime/BUDGET: the numbers may only go down.
+#
+# It also checks two invariants that keep the multi-file runtime honest:
+#   * every .c in lang/runtime/ is either in SOURCES or explicitly optional
+#   * lang/install.sh's hardcoded download list matches SOURCES
+#
+# Exits non-zero on any violation. Run from anywhere; resolves the repo root.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
+
+RUNTIME_DIR="lang/runtime"
+TARGET="$RUNTIME_DIR/el_runtime.c"
+BUDGET_FILE="$RUNTIME_DIR/BUDGET"
+SOURCES_FILE="$RUNTIME_DIR/SOURCES"
+
+FAIL=0
+
+for f in "$TARGET" "$BUDGET_FILE" "$SOURCES_FILE"; do
+  if [ ! -f "$f" ]; then
+    echo "FATAL: required file missing: $f" >&2
+    exit 1
+  fi
+done
+
+budget() {
+  local key="$1"
+  sed -e 's/#.*//' "$BUDGET_FILE" | awk -v k="$key" '$1==k {print $2; found=1} END{if(!found) exit 1}'
+}
+
+MAX_LINES="$(budget max_lines)"       || { echo "FATAL: no 'max_lines' in $BUDGET_FILE" >&2; exit 1; }
+MAX_ENGRAM="$(budget max_engram_fns)" || { echo "FATAL: no 'max_engram_fns' in $BUDGET_FILE" >&2; exit 1; }
+
+# ---------------------------------------------------------------------------
+# The message every failure prints. The guard that existed before this one told
+# you what was wrong but not where the code should go — so it was easy to
+# "fix" by arguing with the guard. This one names the destination.
+# ---------------------------------------------------------------------------
+where_it_goes() {
+  cat >&2 <<'MSG'
+
+  WHERE THE CODE ACTUALLY GOES
+  ----------------------------
+  Placement is a LINK-TIME concern. The compiler cannot tell which .c a symbol
+  came from: `builtin_arity` in el-compiler/src/codegen.el maps NAME -> ARITY
+  INT only, the El name is emitted as the exact C symbol, and `ld` resolves it.
+  The SHIPPED compiler already links from ten translation units — check it:
+
+      nm lang/dist/platform/elc | grep -E 'T _(engram_think|vindex_insert)'
+
+  So a builtin defined in a sibling .c is EXACTLY as linkable as one defined in
+  el_runtime.c. Pick the file that owns the concern:
+
+      engram store ops ......... lang/runtime/engram_store.c
+      ANN / vector index ....... lang/runtime/engram_vindex.c
+      geometry, priming ........ lang/runtime/engram_geometry.c
+      reasoning operators ...... lang/runtime/engram_reason.c
+      grounding, consistency ... lang/runtime/engram_verify.c
+      think, stance ............ lang/runtime/engram_cognition.c
+
+  No existing file owns it?  Create one, add ONE line to lang/runtime/SOURCES,
+  and every build path picks it up. Every runtime file EXCEPT el_runtime.c is
+  deliberately uncapped.
+
+  Belongs to a downstream program, not the runtime?  Declare
+  `c_source "path/to/file.c"` in that program's manifest.el — elb already links
+  it (parse_manifest_c_sources, lang/elb.el:82).
+
+  See lang/AGENTS.md "Where a new C builtin goes".
+MSG
+}
+
+# --- 1. Line-count ratchet ---------------------------------------------------
+LINES="$(wc -l < "$TARGET" | tr -d ' ')"
+if [ "$LINES" -gt "$MAX_LINES" ]; then
+  echo "FAIL: $TARGET grew past its budget." >&2
+  echo "      now:    $LINES lines" >&2
+  echo "      budget: $MAX_LINES lines (lang/runtime/BUDGET: max_lines)" >&2
+  echo "      over by: $((LINES - MAX_LINES))" >&2
+  echo "" >&2
+  echo "This file is a 2026-05-03 build shim that was scheduled for deletion and" >&2
+  echo "never retired. It does not get to grow. Do NOT raise the budget." >&2
+  where_it_goes
+  FAIL=1
+fi
+
+# --- 2. Engram-concern ratchet ----------------------------------------------
+# ~47.5% of el_runtime.c is engram code, and engram already owns six sibling
+# files. This count is the Stage 3 scoreboard: it may only go down.
+ENGRAM_FNS="$(grep -cE '^(static +)?[A-Za-z_][A-Za-z0-9_ *]*\b(engram|eg|cog)_[a-z0-9_]+\(' "$TARGET" || true)"
+if [ "$ENGRAM_FNS" -gt "$MAX_ENGRAM" ]; then
+  echo "FAIL: new engram/eg_/cog_ function(s) added to $TARGET." >&2
+  echo "      now:    $ENGRAM_FNS definitions" >&2
+  echo "      budget: $MAX_ENGRAM (lang/runtime/BUDGET: max_engram_fns)" >&2
+  echo "" >&2
+  echo "Engram code belongs in the six engram_*.c files that already exist." >&2
+  where_it_goes
+  FAIL=1
+fi
+
+# --- 3. Ratchet-down nudge (advisory, never fails) ---------------------------
+if [ "$LINES" -lt "$MAX_LINES" ]; then
+  echo "NOTE: $TARGET is $((MAX_LINES - LINES)) lines under budget — lower" >&2
+  echo "      'max_lines' to $LINES in $BUDGET_FILE in this same commit, so the" >&2
+  echo "      ground you gained cannot be quietly given back." >&2
+fi
+if [ "$ENGRAM_FNS" -lt "$MAX_ENGRAM" ]; then
+  echo "NOTE: $((MAX_ENGRAM - ENGRAM_FNS)) engram fn(s) moved out — lower" >&2
+  echo "      'max_engram_fns' to $ENGRAM_FNS in $BUDGET_FILE in this same commit." >&2
+fi
+
+# --- 4. Every runtime .c is accounted for ------------------------------------
+# A new .c that is in neither SOURCES nor the optional list will not be
+# compiled by any build path — it would be silently dead. Catch that here.
+OPTIONAL_RE='^(el_android|el_gtk4|el_lvgl|el_sdl2|el_win32|el_runtime_win32|eg_cosine_batch_strategy_ggml|vindex_bench)\.c$'
+mapfile -t IN_SOURCES < <(scripts/el-runtime-sources.sh)
+for path in "$RUNTIME_DIR"/*.c; do
+  base="$(basename "$path")"
+  if printf '%s\n' "${IN_SOURCES[@]}" | grep -qxF "$base"; then continue; fi
+  if [[ "$base" =~ $OPTIONAL_RE ]]; then continue; fi
+  echo "FAIL: $path is in neither lang/runtime/SOURCES nor the platform-optional" >&2
+  echo "      list in this guard. It will not be compiled by any build path." >&2
+  echo "      Add it to SOURCES (one line), or add it to OPTIONAL_RE here if it" >&2
+  echo "      is a platform/strategy variant that is linked in deliberately." >&2
+  FAIL=1
+done
+
+# --- 5. install.sh must not drift from SOURCES -------------------------------
+# install.sh runs on machines with no repo checkout, so it cannot call
+# el-runtime-sources.sh and has to hardcode the list. That copy is exactly the
+# kind of duplicate that silently drifted before — so it is checked, not trusted.
+INSTALL_SH="lang/install.sh"
+if [ -f "$INSTALL_SH" ]; then
+  EXPECTED="$(scripts/el-runtime-sources.sh | sort)"
+  ACTUAL="$(sed -n '/^RUNTIME_SOURCES=(/,/^)/p' "$INSTALL_SH" \
+            | grep -oE '[a-z_0-9]+\.c' | sort)"
+  if [ "$EXPECTED" != "$ACTUAL" ]; then
+    echo "FAIL: $INSTALL_SH RUNTIME_SOURCES has drifted from $SOURCES_FILE." >&2
+    echo "      Only in SOURCES:    $(comm -23 <(echo "$EXPECTED") <(echo "$ACTUAL") | tr '\n' ' ')" >&2
+    echo "      Only in install.sh: $(comm -13 <(echo "$EXPECTED") <(echo "$ACTUAL") | tr '\n' ' ')" >&2
+    echo "      An SDK that ships the wrong set produces a lib/ that cannot link." >&2
+    FAIL=1
+  fi
+fi
+
+if [ "$FAIL" -ne 0 ]; then
+  exit 1
+fi
+
+echo "OK: el_runtime.c within budget ($LINES/$MAX_LINES lines, $ENGRAM_FNS/$MAX_ENGRAM engram fns);"
+echo "    runtime sources accounted for; install.sh in step with SOURCES."

scripts/check-single-runtime.sh

@@ -81,14 +81,14 @@ fi
 echo "OK: single canonical runtime source — $CANONICAL (no un-allowlisted forks)."
 
 # ---------------------------------------------------------------------------
-# CI wire-in:
-#   foundation/el .gitea/workflows/ci-dev.yaml, ci-stage.yaml, sdk-release.yaml
-#   Add an early step (before the build/publish steps). It must run from the
-#   REPO ROOT, so override the job's `defaults.run.working-directory: lang`:
+# CI wire-in — DONE (2026-08-16). This block used to describe the wire-in as a
+# TODO, and it had never been done: the guard existed but ran nowhere, so it
+# caught nothing for as long as it has been in the tree. It is now an early step
+# in ci-dev.yaml, ci-stage.yaml and sdk-release.yaml (each with
+# `working-directory: ${{ github.workspace }}`, since the jobs default to lang/),
+# and it runs in .githooks/pre-commit.
 #
-#     - name: Guard - single canonical runtime source
-#       working-directory: ${{ github.workspace }}
-#       run: bash scripts/check-single-runtime.sh
-#
-#   Also add to .githooks/pre-commit so drift is caught before it is committed.
+# Its sibling scripts/check-runtime-growth.sh is wired in at the same points and
+# guards the other half of the problem: this script stops el_runtime.c being
+# COPIED, that one stops it GROWING.
 # ---------------------------------------------------------------------------

scripts/el-runtime-sources.sh

@@ -0,0 +1,73 @@
+#!/usr/bin/env bash
+# el-runtime-sources.sh — print the canonical El runtime link set.
+#
+# Reads lang/runtime/SOURCES (the single source of truth) and prints one path
+# per line, optionally prefixed with a directory. Use it anywhere a link line
+# would otherwise spell the runtime .c files out longhand:
+#
+#   cc -std=c11 -O2 -I lang/runtime -o app app.c \
+#      $(scripts/el-runtime-sources.sh lang/runtime) \
+#      -lcurl -lssl -lcrypto -lpthread -lm
+#
+# Options:
+#   --headers   print the shipped headers instead of the .c sources
+#   --check     verify every listed file exists; exit non-zero if any is missing
+#
+# WHY: linking el_runtime.c alone has been broken since el_runtime.c started
+# calling into the engram siblings. The list was duplicated across ~8 build
+# paths and drifted. It lives in exactly one place now — see lang/runtime/SOURCES.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+SOURCES="${ROOT}/lang/runtime/SOURCES"
+
+if [ ! -f "$SOURCES" ]; then
+  echo "FATAL: canonical runtime source list missing: $SOURCES" >&2
+  exit 1
+fi
+
+MODE="sources"
+PREFIX=""
+CHECK=0
+
+for arg in "$@"; do
+  case "$arg" in
+    --headers) MODE="headers" ;;
+    --check)   CHECK=1 ;;
+    -*)        echo "el-runtime-sources.sh: unknown option: $arg" >&2; exit 2 ;;
+    *)         PREFIX="${arg%/}/" ;;
+  esac
+done
+
+# Strip comments and blank lines. Order is preserved — it is link order.
+mapfile -t FILES < <(sed -e 's/#.*//' -e 's/[[:space:]]*$//' "$SOURCES" | grep -v '^$')
+
+if [ "${#FILES[@]}" -eq 0 ]; then
+  echo "FATAL: $SOURCES lists no sources" >&2
+  exit 1
+fi
+
+if [ "$MODE" = "headers" ]; then
+  # Every .c's matching .h, plus the headers that carry no .c of their own.
+  HDRS=()
+  for f in "${FILES[@]}"; do
+    h="${f%.c}.h"
+    [ -f "${ROOT}/lang/runtime/${h}" ] && HDRS+=("$h")
+  done
+  # Interface-only headers: no matching .c, but required to compile against.
+  for h in eg_cosine_batch_strategy.h el_native_target.h el_platform_win.h; do
+    [ -f "${ROOT}/lang/runtime/${h}" ] && HDRS+=("$h")
+  done
+  FILES=("${HDRS[@]}")
+fi
+
+RC=0
+for f in "${FILES[@]}"; do
+  if [ "$CHECK" -eq 1 ] && [ ! -f "${ROOT}/lang/runtime/${f}" ]; then
+    echo "MISSING: lang/runtime/${f} (listed in lang/runtime/SOURCES)" >&2
+    RC=1
+  fi
+  printf '%s%s\n' "$PREFIX" "$f"
+done
+
+exit $RC