diff --git a/.github/workflows/spec-refs.yml b/.github/workflows/spec-refs.yml
new file mode 100644
index 000000000..4ac3cd8db
--- /dev/null
+++ b/.github/workflows/spec-refs.yml
@@ -0,0 +1,45 @@
+name: spec citations resolve
+
+# Every `SPEC §N` a standard's code cites is a section that standard's SPEC.md
+# has. See the header of scripts/check-spec-refs.py for why: a citation to a
+# section that does not exist reads as authority it does not have, and the three
+# instances found so far were each discovered by reading, long after they were
+# written.
+#
+# Deliberately NO `paths:` filter, for two reasons.
+#
+# The check is one Python pass over the tree — about a second, no toolchain, no
+# cargo — so running it on every change costs less than describing when to run
+# it. And a correct filter here would have to name every standard's `**/*.rs`
+# plus every `SPEC.md`; `standards-build.yml` records that `**`-prefixed globs
+# do not match on this forge the way they do elsewhere, and that a gate which
+# quietly fails to fire is worse than no gate, because it reports nothing and
+# everyone reads that as green. An unfiltered cheap check cannot fail that way.
+#
+# The self-test runs first and on its own line. A check that cannot fail is
+# decoration, and this one would be easy to break into permanent silence — a
+# regex that stops matching finds nothing and exits 0.
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  spec-refs:
+    name: Code cites no section its SPEC lacks
+    runs-on: linux
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: The check can fail (self-test)
+        run: bash scripts/check-spec-refs-selftest.sh
+
+      - name: Every SPEC citation resolves
+        run: python3 scripts/check-spec-refs.py
diff --git a/aac/aac-rs/crates/aac-core/src/obf.rs b/aac/aac-rs/crates/aac-core/src/obf.rs
index aafd7bbc5..78e03821e 100644
--- a/aac/aac-rs/crates/aac-core/src/obf.rs
+++ b/aac/aac-rs/crates/aac-core/src/obf.rs
@@ -33,7 +33,7 @@
 //!   button (message banking), travel in the file: the photo as the button's
 //!   image, the recording as its `sound`, each as a `data:` URI when the
 //!   export is given their bytes ([`ObfExportOptions::media`]).
-//! - A word hidden in place (SPEC §3.3) is a button with `hidden: true`.
+//! - A word hidden in place (SPEC §2.1, §3 item 3) is a button with `hidden: true`.
 //! - AuraSense extensions: `ext_aurasense_locked` (board and button),
 //!   `ext_aurasense_word_class` (the button's part of speech, from the core
 //!   vocabulary) and `ext_aurasense_provenance` (where each piece came from:
diff --git a/aac/aac-rs/crates/aac-web/src/actions.rs b/aac/aac-rs/crates/aac-web/src/actions.rs
index 781fb3abb..a2c99ea0e 100644
--- a/aac/aac-rs/crates/aac-web/src/actions.rs
+++ b/aac/aac-rs/crates/aac-web/src/actions.rs
@@ -93,7 +93,7 @@ pub fn handle_cell_action(
             })
         })
     });
-    // A hidden word keeps its place but cannot be chosen (SPEC §3.3), unless
+    // A hidden word keeps its place but cannot be chosen (SPEC §3.1 item 3), unless
     // hidden words are shown for now: a press there does nothing at all (Help's
     // message stays, words being said go on). A word with no word in the
     // person's language yet is hidden in place too, shown or not.
diff --git a/aac/aac-rs/crates/aac-web/src/components/grid_cell.rs b/aac/aac-rs/crates/aac-web/src/components/grid_cell.rs
index ec905e31e..108ca4527 100644
--- a/aac/aac-rs/crates/aac-web/src/components/grid_cell.rs
+++ b/aac/aac-rs/crates/aac-web/src/components/grid_cell.rs
@@ -10,7 +10,7 @@
 //! always its words.
 //!
 //! A photo the person added takes the symbol's place (media.rs). A hidden
-//! word (SPEC §3.3) keeps its place but looks like an empty one and cannot
+//! word (SPEC §3.1 item 3) keeps its place but looks like an empty one and cannot
 //! be chosen, unless hidden words are shown for now; in Edit mode it shows
 //! faded, and every cell, and every empty place, opens the cell editor
 //! (editing.rs).
diff --git a/sandbox/sandbox-rs/crates/sandbox-build/src/lib.rs b/sandbox/sandbox-rs/crates/sandbox-build/src/lib.rs
index d16adf8a9..248f8c2dd 100644
--- a/sandbox/sandbox-rs/crates/sandbox-build/src/lib.rs
+++ b/sandbox/sandbox-rs/crates/sandbox-build/src/lib.rs
@@ -225,7 +225,8 @@ pub struct BuildTask {
     pub steps: Vec<BuildStep>,
 }
 
-/// The cascade tier that resolved a step (deterministic-first, SPEC §12.1).
+/// The cascade tier that resolved a step (deterministic-first, `spec/build.md`;
+/// the receipt that records it is SPEC §12).
 /// A build never invokes a frontier model *inside* the sandbox — execution is
 /// the deterministic verification — so the only tiers seen here are the cheap
 /// ones: a content-addressed cache hit, or a fresh deterministic execution.
diff --git a/sandbox/sandbox-rs/crates/sandbox-exec-wasm/src/lib.rs b/sandbox/sandbox-rs/crates/sandbox-exec-wasm/src/lib.rs
index 437006f73..6aaae5984 100644
--- a/sandbox/sandbox-rs/crates/sandbox-exec-wasm/src/lib.rs
+++ b/sandbox/sandbox-rs/crates/sandbox-exec-wasm/src/lib.rs
@@ -515,7 +515,8 @@ mod tests {
             .iter()
             .any(|e| matches!(e, sandbox_attest::JournalEntry::HostCall { name, .. } if name == "storage_read")));
 
-        // The brokered I/O is metered as a storage line (SPEC §6.5): one write +
+        // The brokered I/O is metered as a storage line (`spec/receipts.md`,
+        // storage activity — its own axis, outside §6.2's per-device sum): one write +
         // one read ⇒ 2 ops, 7 bytes read ("payload"), an honest estimate.
         let storage = report.storage.expect("storage activity was metered");
         assert_eq!(storage.iops, 2);
diff --git a/scripts/check-spec-refs-selftest.sh b/scripts/check-spec-refs-selftest.sh
new file mode 100755
index 000000000..67e7de4aa
--- /dev/null
+++ b/scripts/check-spec-refs-selftest.sh
@@ -0,0 +1,70 @@
+#!/usr/bin/env bash
+#
+# check-spec-refs-selftest.sh — check-spec-refs.py can fail.
+#
+# A check that cannot fail is decoration. This builds scratch standards under a
+# temporary root and asserts that the check
+#   1. passes when every cited section is a heading;
+#   2. fails when a cited section is not a heading (the case it exists for);
+#   3. accepts both heading spellings, `## 4.` and `## §4`;
+#   4. does NOT synthesise parents: a `## 4.10` heading alone must not satisfy a
+#      `SPEC §4` citation, which is how a standard citing a section it never
+#      wrote would otherwise pass;
+#   5. resolves a citation against the SPEC.md of the standard the file sits in,
+#      so one standard's section cannot excuse another's citation;
+#   6. ignores `*.rs` under a `target/` directory, which is build output.
+# Nothing here reads the real tree, and nothing needs a network.
+set -uo pipefail
+
+here=$(cd "$(dirname "$0")" && pwd)
+check=$here/check-spec-refs.py
+tmp=$(mktemp -d)
+trap 'rm -rf "$tmp"' EXIT
+fails=0
+
+# mk <root> <standard> <spec-headings> <rs-relative-path> <rs-body>
+mk() {
+  mkdir -p "$1/$2/$(dirname "$4")"
+  printf '%s\n' "$3" > "$1/$2/SPEC.md"
+  printf '%s\n' "$5" > "$1/$2/$4"
+}
+
+want() { # want <expect-status> <root> <label>
+  python3 "$check" "$2" > "$tmp/out" 2>&1
+  got=$?
+  if [ "$got" != "$1" ]; then
+    echo "FAIL: $3 — expected exit $1, got $got"
+    sed 's/^/    /' "$tmp/out"
+    fails=$((fails + 1))
+  else
+    echo "ok: $3"
+  fi
+}
+
+r=$tmp/a; mk "$r" alpha '## 4. Flow
+### 4.1 Detail' src/lib.rs '/// Enforces SPEC §4.1 and SPEC §4.'
+want 0 "$r" "passes when every citation resolves"
+
+r=$tmp/b; mk "$r" alpha '## 4. Flow' src/lib.rs '/// Enforces SPEC §4.10.'
+want 1 "$r" "fails on a citation with no heading"
+
+r=$tmp/c; mk "$r" alpha '## §4. Flow
+### §4.1 Detail' src/lib.rs '/// Enforces SPEC §4.1.'
+want 0 "$r" "accepts the section-sign heading spelling"
+
+r=$tmp/d; mk "$r" alpha '### 4.10 Child only' src/lib.rs '/// Enforces SPEC §4.'
+want 1 "$r" "does not let a child heading satisfy its parent"
+
+r=$tmp/e
+mk "$r" alpha '## 7. Only in alpha' src/lib.rs '/// nothing cited here'
+mk "$r" beta  '## 1. Only in beta'  src/lib.rs '/// Enforces SPEC §7.'
+want 1 "$r" "does not resolve beta's citation against alpha's SPEC"
+
+r=$tmp/f; mk "$r" alpha '## 4. Flow' target/debug/build.rs '/// Enforces SPEC §9.'
+want 0 "$r" "ignores .rs under target/"
+
+if [ "$fails" != 0 ]; then
+  echo "check-spec-refs-selftest: $fails case(s) failed."
+  exit 1
+fi
+echo "check-spec-refs-selftest: all cases pass."
diff --git a/scripts/check-spec-refs.py b/scripts/check-spec-refs.py
new file mode 100755
index 000000000..8f3d7d207
--- /dev/null
+++ b/scripts/check-spec-refs.py
@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+"""Every `SPEC §N` a standard's code cites is a section that standard's SPEC.md has.
+
+Code cites normative text to say which rule it implements or enforces. When the
+cited section does not exist, the citation reads as authority it does not have:
+the mechanism is real, gate-enforcing and tested, and nothing normative stands
+behind it. That has happened here repeatedly — `jcp-runtime` cited `SPEC §4.10`
+in six places and §4.10 did not exist (fixed by #190); `aac` cited §3.3 for a
+rule its SPEC states as "§3 item 3"; `sandbox` cited §6.5 and §12.1 for rules
+that live in `spec/receipts.md` and `spec/build.md`. Each was found by reading,
+once, long after it was written. This is that reading, done every time.
+
+What it checks: in each directory holding a `SPEC.md`, every `SPEC §N` (one or
+more parts: §7, §4.10, §2.4.3) appearing in a `*.rs` file under that directory
+resolves to a numbered heading of that same `SPEC.md`. A heading counts when it
+begins `#`…, then the number, with or without `§`, as in `## 7.`, `### 6.4 `,
+`## §3.` or `### §3.1 `.
+
+What it deliberately does not check:
+
+  - Parent numbers are not synthesised. A cited `§4` needs its own `§4` heading;
+    a `§4.10` heading does not satisfy it. A standard that cites a section it
+    never wrote should say so, not be excused by a child.
+  - A citation is resolved against the SPEC.md of the directory the file is in.
+    Every cross-standard citation in the tree today is a self-reference that
+    names its own standard for the reader ("JouleClaw SPEC §1.3", inside
+    jouleclaw/), so this is right for all of them. If a file ever cites another
+    standard's SPEC, resolve it by naming that standard's own file instead —
+    do not loosen this check, which would stop it finding anything.
+  - Sections of a `spec/*.md` subfile are not sections of `SPEC.md`. Rules that
+    live in a subfile should be cited by that file's name, which is what the
+    sandbox fixes above do.
+  - Markdown-to-markdown references are a different check, and WAI's are already
+    covered by `check-wai-section-refs.py`.
+
+Exit status 1, with one line per citation naming a section its SPEC does not
+have; 0 otherwise.
+
+    python3 scripts/check-spec-refs.py [repo-root]
+"""
+import collections
+import os
+import pathlib
+import re
+import sys
+
+HEADING = re.compile(r"^#{1,6}[ \t]+§?([0-9]+(?:\.[0-9]+)*)\.?(?=[ \t])", re.M)
+CITATION = re.compile(r"SPEC[ \t]+§[ \t]*([0-9]+(?:\.[0-9]+)*)")
+
+
+def sections(spec: pathlib.Path) -> set:
+    return set(HEADING.findall(spec.read_text(errors="replace")))
+
+
+def main() -> int:
+    root = pathlib.Path(sys.argv[1] if len(sys.argv) > 1 else
+                        pathlib.Path(__file__).resolve().parent.parent).resolve()
+    standards = sorted(d for d in root.iterdir()
+                       if d.is_dir() and not d.name.startswith(".") and (d / "SPEC.md").is_file())
+    dangling = 0
+    cited_total = 0
+    for s in standards:
+        defined = sections(s / "SPEC.md")
+        found = collections.defaultdict(list)
+        for f in s.rglob("*.rs"):
+            if "target" in f.parts:
+                continue
+            try:
+                text = f.read_text(errors="replace")
+            except OSError:
+                continue
+            if "SPEC" not in text:
+                continue
+            for i, line in enumerate(text.splitlines(), 1):
+                for m in CITATION.finditer(line):
+                    found[m.group(1)].append(f"{f.relative_to(root)}:{i}")
+        cited_total += sum(len(v) for v in found.values())
+        for n, locs in sorted(found.items(), key=lambda kv: [int(x) for x in kv[0].split(".")]):
+            if n in defined:
+                continue
+            for loc in locs:
+                print(f"{loc}: cites SPEC §{n}, which {s.name}/SPEC.md does not define")
+                dangling += 1
+    if dangling:
+        print(f"\ncheck-spec-refs: {dangling} dangling citation(s) across {len(standards)} standards.")
+        print("Either add the section, or cite where the rule actually lives "
+              "(a `spec/*.md` subfile, or a numbered item of a parent section).")
+        return 1
+    print(f"check-spec-refs: {cited_total} citations across {len(standards)} standards, all resolve.")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())