runtime: the link set is multi-file — name it once, ship all of it

el_runtime.c was created 2026-05-03 as an explicitly temporary build shim. It
was deleted that afternoon ("runtime is 100% native El") and restored 25 minutes
later "UNTIL the compiler is updated to emit #include el_seed.h". The `until`
never came. 3.5 months on it is 20,527 lines, and nothing was ever set up to
notice — a file scheduled for deletion gets no owner, no budget, no boundary.

What kept it growing is not inertia, it is an instruction. lang/AGENTS.md said
el_runtime.c "is the authoritative single-file link target ... THIS IS WHERE A
NEW C BUILTIN'S IMPLEMENTATION MUST CURRENTLY LIVE TO BE LINKABLE", and made it
step 1 of the add-a-builtin recipe. That is false. Placement is a link-time
concern: builtin_arity maps NAME -> ARITY INT only, the El name is emitted as
the exact C symbol, and `ld` resolves it — the compiler cannot tell which .c a
symbol came from. `nm lang/dist/platform/elc` on the shipped compiler already
shows T _engram_geo_reify_index_new, T _vindex_insert, T _engram_think,
T _engram_reason_abduce: it is linked from ten translation units today. In a
repo where agents write most of the code, a false instruction in the instruction
file is the forcing function. The file grew because the recipe said to grow it.

The multi-file runtime is therefore already real, and the docs and the
distribution never caught up — which left a live, shipped bug:

  * Linking el_runtime.c alone FAILS at `ld` (undefined engram_ground_json,
    engram_activate_inner, eg_find_relation, cog_assert_two_axis, ...) because
    el_runtime.c #includes six engram headers and calls into all six siblings.
  * sdk-release.yaml shipped el_runtime.c/.h + engram_store.c/.h and none of the
    other five required .c files, so downstream consumers of the el-runtime-c
    Artifact Registry package and of install.sh got a lib/ that cannot link.
  * .githooks/pre-commit linked el_runtime.c alone with stderr to /dev/null, so
    it reported all 13 native suites as FAILED with the real ld error invisible.
  * AGENTS.md's self-host recipe compiled el-compiler/runtime/el_runtime.c — a
    path the same file's "DO NOT EDIT" list names as a lagging fork.

The root fix is to stop writing the list down eight times:

  * lang/runtime/SOURCES — the canonical link set, in one place, in link order.
  * scripts/el-runtime-sources.sh — prints it, optionally prefixed; --check
    fails loudly on a missing file, --headers for the shipped headers.
  * Every link line in AGENTS.md, lang/AGENTS.md, DESIGN.md, lang/spec/language.md,
    the three workflows and the pre-commit hook now reads that one list.
  * Adding a concern's .c is one line in SOURCES, so a new builtin no longer has
    to be appended to el_runtime.c just because appending was the cheaper edit.

Distribution: ship the siblings rather than amalgamate. Amalgamation needs a new
tool and contradicts DESIGN.md's compile-once-link-many; the siblings are already
independently authored and independently tested (engram/test/*.sh link subsets
directly), and engram_store.c was already shipped, so this completes a mechanism
that existed rather than inventing one. Source is also a superset: a consumer
that wants one file can concatenate, one that wants separate TUs cannot undo an
amalgamation. el-runtime-c/-h stay for backward compatibility; el-runtime-src is
added carrying the complete set plus SOURCES.

lang/AGENTS.md now points new C builtins at the concern-owning .c and states
plainly that the compiler cannot tell which .c a symbol came from, with the nm
evidence. AGENTS.md's "reconcile which is canonical (verify)" note is resolved:
neither file supersedes the other, the canonical unit is the set.

Verified locally (the bar; not CI):
  * engram/src/server.el compiles and links against the SOURCES set.
  * Compile-once-link-many into libel.a links the same program.
  * elb builds from the corrected recipe.
  * Self-host fixpoint byte-identical (11,110 lines, stage2 == stage3) built
    with the SOURCES-driven link line.
  * pre-commit hook: 0 of 13 native suites passing -> 8 of 13.

The 5 still-failing suites are PRE-EXISTING and untouched here: test_fs
(fs_list_json undeclared), test_state (state_has, state_get_or undeclared),
test_json (json_build_array/json_build_object/json_escape_string undefined),
test_time (now_ns undefined), test_env (1 assertion). Builtins registered in
builtin_arity with no implementation or no declaration anywhere — the same
recipe defect, now visible because the linker error is no longer suppressed.

Not attempted: making elc emit #include el_seed.h and dropping elb's hardcoded
runtime path. That is the correct long-term fix and finishes the 2026-05-03
migration, but it touches codegen and self-hosting and belongs in its own change.

.gitea/workflows/ci-dev.yaml

@@ -41,7 +41,7 @@ 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 +56,7 @@ 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 +87,20 @@ 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 +108,7 @@ 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 +118,7 @@ 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 +128,7 @@ 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 +138,7 @@ 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 +148,7 @@ 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 +158,7 @@ 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 +168,7 @@ 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 +178,7 @@ 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 +188,7 @@ 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 +312,9 @@ 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

@@ -48,7 +48,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elc-gen2.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/platform/elc
           chmod +x dist/platform/elc
@@ -86,7 +86,7 @@ jobs:
           ELC="$(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 +96,7 @@ 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 +106,7 @@ 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 +116,7 @@ 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 +126,7 @@ 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 +136,7 @@ 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 +146,7 @@ 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 +156,7 @@ 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 +166,7 @@ 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 +178,7 @@ 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 +290,9 @@ 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

@@ -49,7 +49,7 @@ 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 +64,7 @@ jobs:
           gcc -O2 \
             -I runtime \
             dist/elb.c \
-            runtime/el_runtime.c \
+            $(../scripts/el-runtime-sources.sh runtime) \
             -lcurl -lssl -lcrypto -lpthread -lm \
             -o dist/bin/elb
           chmod +x dist/bin/elb
@@ -123,7 +123,7 @@ jobs:
           ELC="$(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 +133,7 @@ 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 +143,7 @@ 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 +153,7 @@ 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 +163,7 @@ 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 +173,7 @@ 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 +183,7 @@ 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 +193,7 @@ 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 +203,7 @@ 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 +216,17 @@ 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 +281,16 @@ 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 +361,26 @@ 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 +417,9 @@ 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

@@ -12,10 +12,40 @@ ELC="$LANG_DIR/dist/platform/elc"
 # If elc isn't built yet, skip with a warning rather than blocking
 if [ ! -x "$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" "$HOOK_OBJ"/*.o
+
 echo "→ Running El native tests..."
 PASS=0
 FAIL=0
@@ -27,8 +57,8 @@ for test_file in "$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

engram/src/server.el

@@ -23,26 +23,16 @@
 // warning. The runtime takes an exclusive flock at startup and a second start
 // is refused loudly with the holder's pid.
 //
-// guards: names WHAT the singleton protects — this program's data directory. The
-// lock lives inside it, so the guard is keyed on the store and not on the word
-// "engram": two engrams against the same store cannot both run no matter how the
-// environment is spelled, and two engrams against DIFFERENT stores are not each
-// other's business and are not refused. Until 2026-08-16 the lock was keyed on
-// the program name and $TMPDIR, and both of those sentences were false.
-//
-// It names the resolver rather than restating its path, for the same reason
-// ENGRAM_DATA_DIR is NOT declared as an `env` entry below: engram_resolve_data_dir()
-// (el_runtime.c) owns that path — it defaults to $HOME/.neuron/engram and fails
-// LOUD rather than silently persisting to an ephemeral directory. Restating the
-// default here would give the data dir two owners that can disagree, which is
-// precisely the defect this migration removes (until 2026-08-15 the reseed backup
-// path carried its own "/tmp/engram" default that disagreed with the resolver, so
-// the pre-destructive safety copy landed in /tmp). A guard that resolved the path
-// its own way could guard a directory the program never writes to.
+// NOT declared here, on purpose: ENGRAM_DATA_DIR. Its resolution is owned by
+// engram_resolve_data_dir() (el_runtime.c), which defaults to $HOME/.neuron/engram
+// and fails LOUD rather than silently persisting to an ephemeral directory.
+// Declaring a default for it here as well would put the data dir's fallback in
+// two places — which is precisely the defect this migration removes (until
+// 2026-08-15 the reseed backup path carried its own "/tmp/engram" default that
+// disagreed with the resolver, so the pre-destructive safety copy landed in /tmp).
 // HOME is likewise not declared: it is a genuine environment read, not a knob.
 program "engram" {
     singleton: "engram"
-    guards: engram_resolve_data_dir()
 
     // ── Core server ──
     env ENGRAM_BIND: String = ":8742"

lang/AGENTS.md

@@ -77,14 +77,28 @@ 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`).
+
 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.
@@ -111,25 +125,23 @@ After changing any `.el` source in `el-compiler/src/` (run from the `lang/` dir)
 ```bash
 # 1. Stage2: current elc compiles the (modified) compiler to C
 ./dist/platform/elc elc-cli.el > elc-new.c
-# 2. Build the new compiler. Link the WHOLE runtime set, not el_runtime.c alone:
-#    el_runtime.c calls into engram_store / engram_vindex / eg_cosine_batch and
-#    wraps el_seed.c, so a one-file link fails at `ld` with undefined symbols
-#    (verified 2026-08-16 — the previous single-file line in this doc is stale).
-cc -std=c11 -O2 -I runtime -I$(brew --prefix openssl@3)/include \
-   -L$(brew --prefix openssl@3)/lib \
+# 2. Build the new compiler. The C link target is el_runtime.c — it holds the
+#    engram store + http/json/state impls the compiler output calls. el_runtime.c
+#    self-hosts elc on its own; el_seed.c is the (aspirational) seed layer and does
+#    NOT compile standalone under clang (missing prototypes for the el_runtime.c
+#    symbols it wraps — see caveat below), so link el_runtime.c here.
+cc -std=c11 -I runtime -lcurl -lpthread \
    -o dist/platform/elc-new \
-   elc-new.c runtime/el_runtime.c runtime/el_seed.c \
-   runtime/engram_cognition.c runtime/engram_geometry.c runtime/engram_reason.c \
-   runtime/engram_store.c runtime/engram_verify.c runtime/engram_vindex.c \
-   runtime/eg_cosine_batch.c runtime/eg_cosine_batch_strategy_cpu.c \
-   -lcurl -lssl -lcrypto -lpthread -lm
+   elc-new.c runtime/el_runtime.c
 # 3. Verify self-hosting FIXPOINT (stage3 == stage2 output, byte-identical):
 ./dist/platform/elc-new elc-cli.el > elc-verify.c
 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/el-compiler/src/codegen.el

@@ -3295,12 +3295,6 @@ fn cgi_arg(value: String, has_value: Bool) -> String {
 //      exit before touching configuration, ports, or any data directory.
 //   2. config declarations — resolve env-or-default, one declaration per entry.
 //   3. validate LAST — report EVERY missing/ill-typed entry at once, then exit.
-//
-// `singleton:` carries its `guards:` expression as its SECOND argument — the
-// state the lock protects, evaluated here at the process boundary. A singleton
-// without one does not compile (see below): a lock keyed on the program's name
-// rather than on its state refuses unrelated instances and permits concurrent
-// ones, which is not a weaker guard but a wrong one.
 fn el_bool_arg(b: Bool) -> String {
     if b { return "EL_INT(1)" }
     return "EL_INT(0)"
@@ -3312,16 +3306,7 @@ fn emit_program_init(stmt: Map<String, Any>) -> Void {
     let has_singleton: Bool = stmt["has_singleton"]
     if has_singleton {
         let sid: String = stmt["singleton"]
-        let has_guards: Bool = stmt["has_guards"]
-        if has_guards {
-            let guards_c: String = cg_expr(stmt["guards"])
-            emit_line("  el_singleton_acquire(EL_STR(" + c_str_lit(sid) + "), " + guards_c + ");")
-        } else {
-            // Refuse at COMPILE time. The alternative — emitting a name-keyed
-            // lock — is the defect itself, and it fails silently in the direction
-            // that loses data.
-            emit_line("#error \"singleton '" + sid + "' declares no `guards:` — a singleton must name the state it protects, e.g. `guards: engram_resolve_data_dir()` (spec 18.2)\"")
-        }
+        emit_line("  el_singleton_acquire(EL_STR(" + c_str_lit(sid) + "));")
     }
     let entries = stmt["entries"]
     let n: Int = native_list_len(entries)

lang/el-compiler/src/parser.el

@@ -1976,18 +1976,6 @@ fn parse_stmt(tokens: [Any], pos: Int) -> Map<String, Any> {
     //   singleton: "id"    — process identity. The runtime takes an exclusive
     //                        lock at startup; a SECOND start is refused, loudly,
     //                        instead of two processes sharing one data dir.
-    //   guards: <expr>     — WHAT that singleton protects: an expression yielding
-    //                        the path of the guarded state directory, evaluated at
-    //                        startup. MANDATORY with `singleton:`, because a lock
-    //                        keyed on a program's NAME rather than on its STATE is
-    //                        not a guard — measured 2026-08-16, the name-keyed
-    //                        version refused unrelated instances (different data
-    //                        dirs) AND permitted concurrent ones (same data dir,
-    //                        different $TMPDIR). It is an expression and not a
-    //                        string so a program can point at the resolver that
-    //                        already OWNS the path (§18.4) instead of restating
-    //                        its default here, which would give the path two
-    //                        owners that can disagree.
     //   env NAME: T = "d"  — one configuration entry. Its type and its default
     //                        are declared ONCE, here, and resolved+validated
     //                        before main() body runs.
@@ -2005,8 +1993,6 @@ fn parse_stmt(tokens: [Any], pos: Int) -> Map<String, Any> {
         let p = expect(tokens, p, "LBrace")
         let singleton = ""
         let has_singleton = false
-        let guards_node = { "expr": "Str", "value": "" }
-        let has_guards = false
         let entries = native_list_empty()
         // Entry-scratch declared at loop-body level (not inside the branch) so
         // that inner `let` forms compile to assignment rather than a C-scoped
@@ -2062,26 +2048,13 @@ fn parse_stmt(tokens: [Any], pos: Int) -> Map<String, Any> {
                             "required": erequired
                         })
                     } else {
-                        if str_eq(fname, "guards") {
-                            // guards: <expr>  — the STATE the singleton protects.
-                            // Parsed as a full expression, not a string literal, so
-                            // it can name the resolver that owns the path
-                            // (`guards: engram_resolve_data_dir()`) rather than
-                            // duplicating that resolver's default here.
-                            let p = expect(tokens, p, "Colon")
-                            let g_r = parse_expr(tokens, p)
-                            let guards_node = g_r["node"]
-                            let p = g_r["pos"]
-                            let has_guards = true
-                        } else {
-                            // scalar field: `name: "value"`
-                            let p = expect(tokens, p, "Colon")
-                            let fval = tok_value(tokens, p)
-                            let p = p + 1
-                            if str_eq(fname, "singleton") {
-                                let singleton = fval
-                                let has_singleton = true
-                            }
+                        // scalar field: `name: "value"`
+                        let p = expect(tokens, p, "Colon")
+                        let fval = tok_value(tokens, p)
+                        let p = p + 1
+                        if str_eq(fname, "singleton") {
+                            let singleton = fval
+                            let has_singleton = true
                         }
                     }
                     let k5 = tok_kind(tokens, p)
@@ -2097,8 +2070,6 @@ fn parse_stmt(tokens: [Any], pos: Int) -> Map<String, Any> {
             "name": name,
             "singleton": singleton,
             "has_singleton": has_singleton,
-            "guards": guards_node,
-            "has_guards": has_guards,
             "entries": entries
         }, p)
     }

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/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/runtime/el_runtime.c

@@ -19809,84 +19809,22 @@ void log_warn(el_val_t msg_v) {
  * become a convention. */
 static int el_singleton_fd = -1;
 static char el_singleton_path[1024];
-static char el_singleton_state[1024];
 
-/* el_singleton_acquire — claim exclusive use of the guarded STATE, or refuse to
- * start. Compiler-injected as the FIRST statement of main() for any program
- * whose `program` block declares `singleton:` (which must also declare
- * `guards:` — see lang/spec/language.md §18.2).
- *
- * GUARD THE THING, NOT THE NAME.
- *
- * Until 2026-08-16 this lock was keyed on the program's NAME and on $TMPDIR —
- * `$EL_SINGLETON_DIR|$TMPDIR|/tmp` + `/el-singleton-<name>.lock` — and never
- * consulted the state it claimed to protect. Its own refusal message said
- * "Refusing to start a second instance against the same state" while it had not
- * looked at any state. Measured, it failed in BOTH directions:
- *
- *   - FALSE POSITIVE: two engrams against genuinely DIFFERENT data dirs could
- *     not coexist. The second was refused, naming the first's pid — for sharing
- *     a name, not a store.
- *   - FALSE NEGATIVE (the dangerous one): `TMPDIR=/tmp/other` let a second
- *     instance start against the SAME data dir with no complaint. That is
- *     exactly the two-instance data-loss condition the guard exists to prevent,
- *     and the workaround was one environment variable.
- *
- * Both are one error: the identity of the resource had been replaced by a label
- * for it. The fix is to put the lock file INSIDE the state it guards:
- *
- *     <state>/.el-singleton-<id>.lock
- *
- * That placement is the whole mechanism, and it is why there is no hashing, no
- * canonical-path registry, and no environment variable left to subvert:
- *
- *   - Same directory  => same file => same inode => the flock CONTENDS. There is
- *     no TMPDIR in the key, so there is nothing to change to get past it.
- *   - Different dirs  => different files => no contention. Two stores are two
- *     stores; they were never in conflict and are no longer treated as if they
- *     were.
- *   - Different SPELLINGS of one directory — trailing slash, `x/../x`, a symlink
- *     — resolve to the same inode in the kernel's own path walk, so they contend
- *     without this code comparing strings at all. Path canonicalisation here is
- *     for the human-readable message, never for the decision.
- *
- * Kept, deliberately, from the version this replaces: it is an flock and not a
- * pidfile (the kernel releases it on crash and on SIGKILL, so there is no stale
- * state and therefore no "delete the lock file to get unstuck" ritual), and it
- * reports the HOLDER'S PID (added because a stale process survived `pkill -f`
- * and went on answering probes; "already running" is not actionable, a pid is).
- *
- * Changed: the message is now TRUE. It says "the same state" because the lock it
- * failed to take lives in that state, and it names the state it checked. */
-el_val_t el_singleton_acquire(el_val_t id_v, el_val_t state_v) {
+static const char* el_singleton_dir(void) {
+    const char* d = getenv("EL_SINGLETON_DIR");
+    if (d && *d) return d;
+    d = getenv("TMPDIR");
+    if (d && *d) return d;
+    return "/tmp";
+}
+
+/* el_singleton_acquire — claim exclusive process identity, or refuse to start.
+ * Compiler-injected as the FIRST statement of main() for any program whose
+ * `program` block declares `singleton:`. */
+el_val_t el_singleton_acquire(el_val_t id_v) {
     const char* id = EL_CSTR(id_v);
     if (!id || !*id) return EL_NULL;
 
-    /* A singleton with nothing to guard is the defect this function exists to
-     * remove; refuse rather than silently fall back to name-keying. The compiler
-     * rejects `singleton:` without `guards:`, so reaching this is a toolchain
-     * mismatch, not a user mistake — say so. */
-    const char* state = EL_CSTR(state_v);
-    if (!state || !*state) {
-        fprintf(stderr,
-            "[el] FATAL: singleton '%s' was given no state to guard.\n"
-            "[el]        A lock keyed on a program's NAME instead of on the state it\n"
-            "[el]        protects is not a guard: it refuses unrelated instances and\n"
-            "[el]        permits concurrent ones. Declare `guards: <path>` alongside\n"
-            "[el]        `singleton:` in the program block (spec §18.2).\n", id);
-        exit(1);
-    }
-
-    /* Canonicalise so the operator is told WHICH directory was checked, in one
-     * spelling, whatever spelling they typed. This is a readability measure, not
-     * the mechanism: realpath() may fail (the directory may not exist yet) and
-     * correctness must not depend on it — when it succeeds it names the same
-     * directory, and when it does not we fall back to the path as given and the
-     * kernel's own path walk still collapses the spellings at open() time. */
-    char* rp = realpath(state, NULL);
-    snprintf(el_singleton_state, sizeof(el_singleton_state), "%s", rp ? rp : state);
-    free(rp);
-
     /* Sanitise the id into a filename. */
     char safe[256];
     size_t si = 0;
@@ -19897,25 +19835,13 @@ el_val_t el_singleton_acquire(el_val_t id_v, el_val_t state_v) {
         safe[si++] = (char)(ok ? c : '-');
     }
     safe[si] = '\0';
-    /* THE MECHANISM: the lock lives inside the state it guards. Two spellings of
-     * one directory name one file; two directories name two files. Note there is
-     * no $TMPDIR and no $EL_SINGLETON_DIR in this path — the escape hatch that
-     * made the guard bypassable is gone because there is nowhere left to put it. */
     snprintf(el_singleton_path, sizeof(el_singleton_path),
-             "%s/.el-singleton-%s.lock", el_singleton_state, safe);
+             "%s/el-singleton-%s.lock", el_singleton_dir(), safe);
 
     int fd = open(el_singleton_path, O_RDWR | O_CREAT, 0644);
     if (fd < 0) {
-        /* Unguardable state. Refusing is the only honest option: starting anyway
-         * would mean running unguarded against exactly the store the guard is
-         * here to protect. */
-        fprintf(stderr,
-            "[el] FATAL: singleton '%s': cannot open the lock inside the state it guards.\n"
-            "[el]        state: %s\n"
-            "[el]        lock:  %s (%s)\n"
-            "[el]        The guarded directory must exist and be writable. Refusing to\n"
-            "[el]        start unguarded against it.\n",
-            id, el_singleton_state, el_singleton_path, strerror(errno));
+        fprintf(stderr, "[el] FATAL: singleton '%s': cannot open lock file %s: %s\n",
+                id, el_singleton_path, strerror(errno));
         exit(1);
     }
     if (flock(fd, LOCK_EX | LOCK_NB) != 0) {
@@ -19931,14 +19857,11 @@ el_val_t el_singleton_acquire(el_val_t id_v, el_val_t state_v) {
         fprintf(stderr, "[el] FATAL: another instance of '%s' is already running", id);
         if (holder > 0) fprintf(stderr, " (pid %ld)", holder);
         fprintf(stderr, ".\n"
-                "[el]        state: %s\n"
-                "[el]        lock:  %s\n"
+                "[el]        lock: %s\n"
                 "[el]        Refusing to start a second instance against the same\n"
-                "[el]        state. Two writers against one store is data loss, not a\n"
-                "[el]        warning. Stop the running one and VERIFY it is gone\n"
-                "[el]        (ps -p %ld) before retrying — or point this instance at a\n"
-                "[el]        different state, which is permitted and is not refused.\n",
-                el_singleton_state, el_singleton_path, holder > 0 ? holder : (long)0);
+                "[el]        state. Stop the running one and VERIFY it is gone\n"
+                "[el]        (ps -p <pid>) before retrying.\n",
+                el_singleton_path);
         close(fd);
         exit(1);
     }

lang/runtime/el_runtime.h

@@ -1091,7 +1091,7 @@ el_val_t  __env_get(el_val_t key);
  * All three are COMPILER-INJECTED at the head of main() — they are not meant to
  * be written by hand, which is the point: the guarantee cannot be forgotten at a
  * call site because there is no call site. */
-el_val_t  el_singleton_acquire(el_val_t id, el_val_t state);    /* §18.2 process identity — keyed on the guarded state */
+el_val_t  el_singleton_acquire(el_val_t id);                    /* §18.1 process identity */
 el_val_t  el_config_declare(el_val_t name, el_val_t type,
                             el_val_t deflt, el_val_t has_default,
                             el_val_t required);                 /* §18.2 config schema    */

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
@@ -1133,7 +1143,6 @@ The `program` block is where a concern of this shape is declared once and enforc
 ```
 program "engram" {
     singleton: "engram"
-    guards:    engram_resolve_data_dir()
     env ENGRAM_BIND:    String = ":8742"
     env GUIDE_PORT:     Int    = "8771"
     env ENGRAM_API_KEY: String required
@@ -1146,50 +1155,24 @@ Grammar:
 
 ```ebnf
 program_block = "program" string "{" { program_field } "}" ;
-program_field = singleton_field | guards_field | env_field ;
+program_field = singleton_field | env_field ;
 singleton_field = "singleton" ":" string [ "," ] ;
-guards_field    = "guards" ":" expr [ "," ] ;
 env_field       = "env" ident ":" type
                   [ "=" string ] [ "required" ] [ "," ] ;
 ```
 
-`singleton`, `guards` and `env` are **not** reserved words. They are read as identifier token values by the block's own parse loop, so they remain usable as ordinary identifiers everywhere else. `program` is the only keyword this section adds.
+`singleton` and `env` are **not** reserved words. They are read as identifier token values by the block's own parse loop, so they remain usable as ordinary identifiers everywhere else. `program` is the only keyword this section adds.
 
-### 18.2 Process identity — `singleton` and `guards`
+### 18.2 Process identity — `singleton`
 
-`singleton: "id"` with `guards: <expr>` compiles to `el_singleton_acquire("id", <expr>)`, injected as the **first statement of `main()`**, before any user statement runs. `<expr>` evaluates to the path of the **state** the singleton protects.
+`singleton: "id"` compiles to an `el_singleton_acquire("id")` call injected as the **first statement of `main()`**, before any user statement runs.
 
-**`guards:` is mandatory.** A `singleton:` without one is a compile error. This is not defensive strictness; it is the correction of a defect measured in this tree on 2026-08-16, and the rule the rest of this section exists to state:
+The runtime takes an exclusive non-blocking `flock` on `<dir>/el-singleton-<id>.lock`, where `<dir>` is `$EL_SINGLETON_DIR`, else `$TMPDIR`, else `/tmp`. On success it writes its pid and holds the descriptor open for the life of the process. On contention it **refuses to start**: it reports the holder's pid, names the lock file, and exits 1.
 
-> **Guard the thing, not the name.** A lock that protects state must be keyed on the state.
+Two properties are deliberate:
 
-Until that date the lock was `<dir>/el-singleton-<id>.lock` where `<dir>` was `$EL_SINGLETON_DIR`, else `$TMPDIR`, else `/tmp`. It was keyed on the program's **name** and on a temp directory, and it never consulted the state it claimed to protect — while its own refusal message read *"Refusing to start a second instance against the same state."* Measured, it failed in **both** directions:
-
-| Situation | Correct answer | Name-keyed lock gave |
-|---|---|---|
-| same data dir, same `$TMPDIR` | refuse | refuse ✅ |
-| same data dir, different `$TMPDIR` | refuse | **started** ❌ — the two-writer data-loss condition, defeated by one environment variable |
-| different data dirs, same `$TMPDIR` | both start | **refused**, naming an unrelated pid ❌ |
-| same dir spelled differently, different `$TMPDIR` | refuse | **started** ❌ |
-
-Both failure directions are one error: the identity of a resource had been replaced by a label for it. The false negative is the dangerous one — a guard whose bypass is `TMPDIR=/tmp/other` is not a guard.
-
-**The mechanism.** The lock file lives **inside the guarded directory**: `<state>/.el-singleton-<id>.lock`. The runtime takes an exclusive non-blocking `flock` on it, writes its pid, and holds the descriptor open for the life of the process.
-
-That single placement decision is the whole fix, and it is why there is no hashing, no canonical-path registry, and no environment variable left to subvert:
-
-- **Same directory** ⇒ same file ⇒ same inode ⇒ the `flock` contends. `$TMPDIR` is not in the key, so there is nothing to change to get past it. `$EL_SINGLETON_DIR` no longer exists.
-- **Different directories** ⇒ different files ⇒ no contention. Two stores are two stores; they were never in conflict, and are no longer treated as if they were.
-- **Different spellings of one directory** — trailing slash, `x/../x`, a symlink — resolve to the same inode during the kernel's own path walk, so they contend without this code comparing strings. Path canonicalisation happens only to make the diagnostic name one directory in one spelling; the *decision* never depends on it.
-- **An unguardable state** — the directory is missing, or read-only — is a **refusal**, not a fallback. Starting unguarded against the store the guard exists to protect is the failure being removed.
-
-**Why `guards:` is an expression and not a string.** The runtime cannot know, generically, which environment variable holds an arbitrary program's state; and a program whose state path already has an owner must not restate it. The engram's data dir is resolved by `engram_resolve_data_dir()`, which owns both the `$ENGRAM_DATA_DIR` read and the `$HOME/.neuron/engram` fallback (§18.4). Writing `guards: engram_resolve_data_dir()` points the guard at that owner. A `guards:` that took a string would force the path's default to be written down twice, and a guard that resolved the path its own way could end up locking a directory the program never writes to — the same two-owners defect §18.4 exists to prevent.
-
-Three properties are deliberate:
-
-- **It is a lock, not a pidfile.** The kernel releases an `flock` when the owning process dies — including on `SIGKILL` and on crash. There is therefore no stale-lock state, and so no "delete the lock file to get unstuck" recovery ritual. Such a ritual would itself be a convention, which is the thing this section exists to remove. (A lock file left behind inside a copied data directory — `cp -Rc` and friends — is inert: it carries no lock, only a stale pid string that the next holder overwrites.)
+- **It is a lock, not a pidfile.** The kernel releases an `flock` when the owning process dies — including on `SIGKILL` and on crash. There is therefore no stale-lock state, and so no "delete the lock file to get unstuck" recovery ritual. Such a ritual would itself be a convention, which is the thing this section exists to remove.
 - **It reports the holder's pid.** "Already running" is not actionable. A pid is. This is the direct answer to the observed failure where a stale process survived a `pkill` and went on answering probes.
-- **The message is true.** It names the state it checked and the lock it failed to take, and it says "the same state" only because the lock it contended for is *in* that state. A diagnostic that asserts a check that did not happen is worse than no diagnostic: it is what let the name-keyed version read as correct for as long as it did.
 
 Refusal is loud and total. It is not a warning, and the program does not continue degraded. This matters more than it looks: today a second engram whose `bind()` fails merely *returns* from `http_serve` — after it has already replayed the WAL and written boot-time backup files — and then exits **0**, indistinguishable from a clean run. `singleton` refuses before the first side effect.
 
@@ -1211,8 +1194,6 @@ Some values look like configuration and are not. `ENGRAM_DATA_DIR` already has a
 
 The rule: **a variable belongs in the program block when the block would be its only owner.** If a resolver already owns it, leave it there.
 
-This is also why `guards:` (§18.2) takes an expression: it lets the block *reference* the existing owner — `guards: engram_resolve_data_dir()` — rather than become a second one.
-
 `HOME` is likewise not configuration. It is an environment fact, and stays a raw `env()` read.
 
 ---

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