diff --git a/.github/labeler.yml b/.github/labeler.yml
index 1859654..aa1a7aa 100644
--- a/.github/labeler.yml
+++ b/.github/labeler.yml
@@ -32,9 +32,12 @@ scope:guards:
           - actions/changelog-armed/**
           - actions/changelog-monotonic/**
           - actions/drill-recorded/**
+          - actions/refs-not-closing/**
+          - .github/workflows/refs-guard.yml
           - test/changelog-armed.test.sh
           - test/changelog-monotonic.test.sh
           - test/drill-recorded.test.sh
+          - test/refs-not-closing.test.sh
 scope:labels:
   - changed-files:
       - any-glob-to-any-file:
diff --git a/.github/workflows/refs-guard.yml b/.github/workflows/refs-guard.yml
new file mode 100644
index 0000000..ef4964e
--- /dev/null
+++ b/.github/workflows/refs-guard.yml
@@ -0,0 +1,18 @@
+name: Refs guard
+
+on:
+  # Body edits are load-bearing: #200 gained its accidental closing keyword
+  # after the PR opened, with no new commit to wake ordinary CI (#218).
+  pull_request:
+    types: [opened, edited, reopened, synchronize]
+
+permissions:
+  contents: read
+  pull-requests: read
+
+jobs:
+  refs-not-closing:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: ./actions/refs-not-closing
diff --git a/BUILDER.md b/BUILDER.md
index 9066716..d8376ea 100644
--- a/BUILDER.md
+++ b/BUILDER.md
@@ -182,6 +182,13 @@ triage bug, and the move is to say so on the issue, not to guess.
   absent that instruction `Closes #N` remains the default. The exception was
   bought the hard way: #143 carried `Closes #137` as doctrine then required,
   and the merge closed #137 with its post-merge criterion unmet (#151).
+  On a `Refs #N` PR, never put a closing keyword (`close`, `closes`,
+  `closed`, `fix`, `fixes`, `fixed`, `resolve`, `resolves`, `resolved`)
+  immediately before `#N` anywhere in the body — including the sentence
+  explaining why the PR does not close it. GitHub reads the whole body by
+  adjacency, not intent. Put the number first (`#N is closed by hand`) or
+  omit it (`triage closes the issue by hand`). A code span does not protect
+  the phrase: a backticked `Closes #199` still closed #199 (#200, #218).
   Drafts are invisible to the reviewer panel on
   purpose — the draft phase is yours.
 - **The issue's acceptance criteria are your definition of done.** Reproduce
diff --git a/REVIEWER.md b/REVIEWER.md
index f41565b..7d8e74e 100644
--- a/REVIEWER.md
+++ b/REVIEWER.md
@@ -34,7 +34,12 @@ In order of authority:
    not a defect: the issue directs it, triage owns that close, and a
    request-changes on the "missing" keyword enforces the bug the shape
    exists to fix — `Closes #137` closed its issue with a post-merge
-   criterion unmet (#151). Check every
+   criterion unmet (#151). For a `Refs #N` body, also verify that no closing
+   keyword immediately precedes `#N` anywhere in the body, even in prose
+   explaining the hand close or inside a code span: GitHub used those exact
+   shapes to close #209, #212 and #199 (#200, #218). The safe forms put the
+   number first (`#N is closed by hand`) or omit it (`triage closes the issue
+   by hand`). Check every
    criterion; a PR that ships less than the issue says is a request-changes
    even if the code is beautiful.
 2. **The repo's load-bearing constraints** — the rules bought with
diff --git a/actions/refs-not-closing/action.yml b/actions/refs-not-closing/action.yml
new file mode 100644
index 0000000..10ffeae
--- /dev/null
+++ b/actions/refs-not-closing/action.yml
@@ -0,0 +1,16 @@
+name: Refs not closing
+description: >-
+  Refuse a pull request whose `Refs #N` promise contradicts GitHub's
+  closing-issue graph (#218). GitHub recognizes closing keywords anywhere
+  in a PR body, including ordinary prose and code spans; the action reads
+  the graph once and lets a pure script decide whether any Refs target is
+  already scheduled to close.
+runs:
+  using: composite
+  steps:
+    - name: refs targets are not closing
+      shell: bash
+      env:
+        GH_TOKEN: ${{ github.token }}
+        PR_NUMBER: ${{ github.event.pull_request.number }}
+      run: bash "$GITHUB_ACTION_PATH/run.sh"
diff --git a/actions/refs-not-closing/refs-not-closing.sh b/actions/refs-not-closing/refs-not-closing.sh
new file mode 100755
index 0000000..0f2af98
--- /dev/null
+++ b/actions/refs-not-closing/refs-not-closing.sh
@@ -0,0 +1,124 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# refs-not-closing.sh <body-file> [<closing-issue-number> ...] — compare the
+# issues a PR promises merely to reference with GitHub's closing-issue graph
+# (#218). The graph is authoritative because it includes both closing
+# keywords and sidebar links. The body still matters: only an issue named by
+# `Ref #N` or `Refs #N` is protected, so an ordinary `Closes #N` PR remains
+# untouched.
+#
+# This decision stays network-free so test/refs-not-closing.test.sh can drive
+# the incident matrix offline. The composite action gathers both facts in one
+# GraphQL read and passes them here. A failed or partial read never reaches
+# this script: action.yml refuses it before asking for a verdict.
+
+body_file="${1:-}"
+shift || true
+
+if [ -z "$body_file" ] || [ ! -f "$body_file" ]; then
+  echo "refs-not-closing: body file is missing or unreadable: ${body_file:-<none>}" >&2
+  exit 1
+fi
+
+declare -A closing=()
+for issue in "$@"; do
+  case "$issue" in
+    ''|*[!0-9]*)
+      echo "refs-not-closing: invalid closing issue number: '$issue'" >&2
+      exit 1
+      ;;
+  esac
+  closing["$issue"]=1
+done
+
+mapfile -t refs_targets < <(
+  awk '
+    {
+      rest = tolower($0)
+      while (match(rest, /(^|[^[:alnum:]_])refs?[[:space:]]*:?[[:space:]]*[[]?#[0-9]+/)) {
+        token = substr(rest, RSTART, RLENGTH)
+        sub(/^.*#/, "", token)
+        print token + 0
+        rest = substr(rest, RSTART + RLENGTH)
+      }
+    }
+  ' "$body_file" | sort -nu
+)
+
+intersections=()
+for issue in "${refs_targets[@]}"; do
+  if [ -n "${closing[$issue]:-}" ]; then
+    intersections+=("$issue")
+  fi
+done
+
+if [ "${#intersections[@]}" -eq 0 ]; then
+  echo "refs-not-closing: no Refs target appears in GitHub's closing-issue graph"
+  exit 0
+fi
+
+sentence_for_issue() {
+  local issue="$1" mode="$2"
+  awk -v issue="$issue" -v mode="$mode" '
+    /^[[:space:]]*$/ {
+      if (paragraph != "") {
+        text = text paragraph "\n\n"
+        paragraph = ""
+      }
+      next
+    }
+    {
+      if (paragraph != "") paragraph = paragraph " "
+      paragraph = paragraph $0
+    }
+    END {
+      text = text paragraph
+      count = split(text, sentence, /[.!?][[:space:]]+|\n\n+/)
+      if (mode == "closing") {
+        needle = "(^|[^[:alnum:]_])(close|closes|closed|fix|fixes|fixed|resolve|resolves|resolved)[[:space:]]+#[[:space:]]*" issue "([^0-9]|$)"
+      } else {
+        needle = "(^|[^[:alnum:]_])refs?[[:space:]]*:?[[:space:]]*\\[?#[[:space:]]*" issue "([^0-9]|$)"
+      }
+      for (i = 1; i <= count; i++) {
+        lower = tolower(sentence[i])
+        if (match(lower, needle)) {
+          matched = substr(sentence[i], RSTART, RLENGTH)
+          sub(/^[^[:alnum:]_]*/, "", matched)
+          sub(/[^0-9]*$/, "", matched)
+          gsub(/^[[:space:]]+|[[:space:]]+$/, "", sentence[i])
+          printf "%s\t%s\n", matched, sentence[i]
+          exit
+        }
+      }
+    }
+  ' "$body_file"
+}
+
+{
+  printf 'refs-not-closing: Refs target(s) also scheduled to close:'
+  printf ' #%s' "${intersections[@]}"
+  printf '\n'
+
+  for issue in "${intersections[@]}"; do
+    detail="$(sentence_for_issue "$issue" closing)"
+    if [ -z "$detail" ]; then
+      detail="$(sentence_for_issue "$issue" refs)"
+      printf "  #%s: GitHub reports a closing reference; no adjacent closing keyword was found, so inspect the Development sidebar link.\n" "$issue"
+    fi
+    if [ -n "$detail" ]; then
+      matched="${detail%%$'\t'*}"
+      sentence="${detail#*$'\t'}"
+      printf '    matched: %s\n' "$matched"
+      printf '    sentence: %s\n' "$sentence"
+    fi
+  done
+
+  cat <<'EOF'
+  A `Refs #N` PR must not close N. Remove the sidebar closing link or rewrite
+  an adjacent closing-keyword sentence so the number comes first (`#N is
+  closed by hand`) or the number is omitted (`triage closes the issue by
+  hand`). Backticks do not protect a closing keyword from GitHub's parser.
+EOF
+} >&2
+exit 1
diff --git a/actions/refs-not-closing/run.sh b/actions/refs-not-closing/run.sh
new file mode 100755
index 0000000..6a0dd4a
--- /dev/null
+++ b/actions/refs-not-closing/run.sh
@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# The composite action's executable boundary (#218). Keeping the GraphQL
+# gather here lets the offline contract test replace `gh` and prove that
+# failed and partial reads cannot accidentally produce a green verdict.
+
+owner="${GITHUB_REPOSITORY%%/*}"
+name="${GITHUB_REPOSITORY#*/}"
+[ -n "${PR_NUMBER:-}" ] || {
+  echo "refs-not-closing: pull request number is unavailable" >&2
+  exit 1
+}
+
+# GraphQL variables are literal API syntax; the shell must not expand them.
+# shellcheck disable=SC2016
+facts="$(gh api graphql \
+  -f query='query($owner: String!, $name: String!, $number: Int!) {
+    repository(owner: $owner, name: $name) {
+      pullRequest(number: $number) {
+        body
+        closingIssuesReferences(first: 100) {
+          nodes { number }
+          pageInfo { hasNextPage }
+        }
+      }
+    }
+  }' \
+  -F owner="$owner" -F name="$name" -F number="$PR_NUMBER")"
+
+body_file="$(mktemp)"
+closing_file="$(mktemp)"
+trap 'rm -f "$body_file" "$closing_file"' EXIT
+jq -er '
+  .data.repository.pullRequest
+  | if . == null then error("pull request was not returned") else .body // "" end
+' <<<"$facts" >"$body_file"
+jq -r '
+  .data.repository.pullRequest.closingIssuesReferences
+  | if . == null then
+      error("closing issue references were not returned")
+    elif .pageInfo.hasNextPage then
+      error("more than 100 closing issue references; refusing a partial verdict")
+    else
+      .nodes[].number
+    end
+' <<<"$facts" >"$closing_file"
+
+mapfile -t closing_issues <"$closing_file"
+bash "$GITHUB_ACTION_PATH/refs-not-closing.sh" \
+  "$body_file" "${closing_issues[@]}"
diff --git a/changelog.d/218.md b/changelog.d/218.md
new file mode 100644
index 0000000..cdbdc46
--- /dev/null
+++ b/changelog.d/218.md
@@ -0,0 +1,4 @@
+### Added
+
+- Pull requests that promise `Refs #N` now fail a read-only, body-edit-aware
+  guard if GitHub would close N through a keyword or sidebar link (#218).
diff --git a/docs/CONSUMERS.md b/docs/CONSUMERS.md
index 437d64b..fc12b4c 100644
--- a/docs/CONSUMERS.md
+++ b/docs/CONSUMERS.md
@@ -124,14 +124,41 @@ the machinery at all:
    consumer. In particular, `0.1.0` carries `changelog-armed`,
    `changelog-monotonic` and `drill-recorded` plus `docs-sync`, but not
    `changelog-assembled` or `runner-isolated`.
-6. **Labels automation** (optional but recommended): the two callers from
+6. **`.github/workflows/refs-guard.yml`** — the body-aware guard is its own
+   caller because `edited` is load-bearing: #200 gained its accidental
+   closing keyword after the PR opened, with no push to wake ordinary CI.
+   It costs the consumer one read-only workflow file and no other machinery:
+
+   ```yaml
+   name: Refs guard
+
+   on:
+     pull_request:
+       types: [opened, edited, reopened, synchronize]
+
+   permissions:
+     contents: read
+     pull-requests: read
+
+   jobs:
+     refs-not-closing:
+       runs-on: ubuntu-latest
+       steps:
+         - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+         - uses: heavy-duty/ceremony/actions/refs-not-closing@<pinned-tag>
+   ```
+
+   `refs-not-closing` is **unreleased** until the first tag carrying #218.
+   Adopt this caller with that ordinary pin bump; never point only this file
+   at a moving or newer ref.
+7. **Labels automation** (optional but recommended): the two callers from
    [Labels automation](#labels-automation) — the event-facing labels
    caller and the sweep caller (#209) — plus `.github/labels.conf`
    (panel + the repo's `scope:*` rows) and `.github/labeler.yml` (the
    path→scope globs). Run the sweep caller's `workflow_dispatch` once —
    **this bootstraps the taxonomy, `release` label included** — and use it
    again whenever an operator needs a full-board sweep immediately.
-7. **The artifact hook** (optional): `.github/actions/release-artifact/`
+8. **The artifact hook** (optional): `.github/actions/release-artifact/`
    per [The artifact hook](#the-artifact-hook). No hook → the source
    tarball is the package.
 
@@ -156,6 +183,8 @@ precisely so the machinery is safe to work on
       sibling `push:` silently kills a door (rig's review catch).
 - [ ] Swap the guard *script* steps in `ci.yml` for the `uses:` steps in
       the bootstrap list above (with `fetch-depth: 0` on the checkout).
+- [ ] Add `refs-guard.yml` from the bootstrap list with the same ceremony
+      pin as the release caller and CI guard steps.
 - [ ] Replace `labels.yml` with the caller from
       [Labels automation](#labels-automation) and add the sweep caller
       `labels-sweep.yml` beside it (#209); extract
diff --git a/test/refs-not-closing.test.sh b/test/refs-not-closing.test.sh
new file mode 100755
index 0000000..b81a2dd
--- /dev/null
+++ b/test/refs-not-closing.test.sh
@@ -0,0 +1,156 @@
+#!/usr/bin/env bash
+# Contract tests for actions/refs-not-closing (issue #218). Bodies and
+# closing-reference sets are fixtures: no network and no pull request are
+# involved. set -u, not -e: failures are behavior for the harness to inspect.
+set -u
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+# shellcheck source=test/harness.sh
+. "$ROOT/test/harness.sh"
+
+SCRIPT="$ROOT/actions/refs-not-closing/refs-not-closing.sh"
+ACTION="$ROOT/actions/refs-not-closing/action.yml"
+ENTRYPOINT="$ROOT/actions/refs-not-closing/run.sh"
+WORKFLOW="$ROOT/.github/workflows/refs-guard.yml"
+
+TMP="$(mktemp -d)"
+trap 'rm -rf "$TMP"' EXIT
+
+body() {
+  local name="$1"
+  shift
+  printf '%s\n' "$@" >"$TMP/$name.md"
+}
+
+guard() {
+  local name="$1"
+  shift
+  bash "$SCRIPT" "$TMP/$name.md" "$@"
+}
+
+body ref-5 'Refs #5'
+check "Refs target with empty closing set passes" 0 "no Refs target" guard ref-5
+check "Refs target with itself closing fails" 1 "#5" guard ref-5 5
+check "Refs target with another issue closing passes" 0 "no Refs target" guard ref-5 9
+
+body ordinary 'Closes #5'
+check "ordinary Closes PR remains green" 0 "no Refs target" guard ordinary 5
+
+body mixed 'Refs #5' '' 'This PR legitimately Closes #9.'
+check "Refs #5 plus Closes #9 remains green" 0 "no Refs target" guard mixed 9
+
+body prose 'Refs #5' '' 'Triage closes #5 by hand after the live proof.'
+check "closing prose for a Refs target fails" 1 "closes #5" guard prose 5
+check "failure prints the surrounding sentence" 1 \
+  "sentence: Triage closes #5 by hand after the live proof" guard prose 5
+check "failure offers number-first rewrite" 1 "#N is" guard prose 5
+check "failure offers number-free rewrite" 1 "closes the issue" guard prose 5
+
+body code-span 'Refs #5' '' "The body must not contain \`Closes #5\` anywhere."
+check "backticked closing keyword is reported as the match" 1 \
+  "matched: Closes #5" guard code-span 5
+check "backtick failure explains that code spans do not protect" 1 \
+  "Backticks do not protect" guard code-span 5
+
+body adjacency 'Refs #5' '' 'Triage closes #9 and #5 after the proof.'
+check "non-adjacent #5 does not join closing set #9" 0 "no Refs target" \
+  guard adjacency 9
+
+body empty ''
+check "empty body remains green" 0 "no Refs target" guard empty 5
+
+body incidents-211 'Refs #209' 'Triage closes #209 by hand.'
+check "#211 incident replays red" 1 "#209" guard incidents-211 209
+body incidents-214 'Refs #212' 'Triage closes #212 and #209 on that evidence.'
+check "#214 incident replays red" 1 "#212" guard incidents-214 212
+body incidents-200 'Refs #199' "A later edit added \`Closes #199\`."
+check "#200 incident replays red" 1 "#199" guard incidents-200 199
+
+body multiple 'Refs #5 and Refs #7.' 'Triage closes #5 and fixes #7 by hand.'
+check "failure names every intersecting issue" 1 \
+  "scheduled to close: #5 #7" guard multiple 5 7
+
+body soft-wrap 'Refs #5' '' 'Triage closes' '#5 by hand after the live proof.'
+check "soft-wrapped closing prose is reported as one sentence" 1 \
+  "sentence: Triage closes #5 by hand after the live proof" \
+  guard soft-wrap 5
+
+body refs-colon 'Refs: #5' '' 'Triage closes #5 after proof.'
+check "Refs colon form is protected" 1 "matched: closes #5" \
+  guard refs-colon 5
+body refs-link 'Refs [#5](https://example.test/issues/5)' '' \
+  'Triage closes #5 after proof.'
+check "linked Refs form is protected" 1 "matched: closes #5" \
+  guard refs-link 5
+
+for number in 207 191 190 176 165 164; do
+  body "incident-$number" "Refs #$number"
+  check "#$number incident replays green" 0 "no Refs target" \
+    guard "incident-$number"
+done
+
+check "missing body is a loud failure" 1 "missing or unreadable" \
+  bash "$SCRIPT" "$TMP/missing.md"
+check "invalid closing set is a loud failure" 1 "invalid closing issue" \
+  guard ref-5 nope
+
+# The action owns the network boundary. Drive its executable entrypoint with
+# a fake `gh` so failures are behavioral assertions, not YAML text guesses.
+mkdir -p "$TMP/bin"
+cat >"$TMP/bin/gh" <<'EOF'
+#!/usr/bin/env bash
+set -u
+case "${FAKE_GH_MODE:-success}" in
+  failure)
+    echo "fake GraphQL read failed" >&2
+    exit 42
+    ;;
+  partial)
+    has_next=true
+    ;;
+  success)
+    has_next=false
+    ;;
+  *)
+    echo "unknown fake mode: ${FAKE_GH_MODE:-}" >&2
+    exit 2
+    ;;
+esac
+printf '{"data":{"repository":{"pullRequest":{"body":"Refs #5","closingIssuesReferences":{"nodes":[],"pageInfo":{"hasNextPage":%s}}}}}}\n' "$has_next"
+EOF
+chmod +x "$TMP/bin/gh"
+
+action_boundary() {
+  local mode="$1"
+  env PATH="$TMP/bin:$PATH" FAKE_GH_MODE="$mode" \
+    GITHUB_REPOSITORY="heavy-duty/ceremony" PR_NUMBER=268 \
+    GITHUB_ACTION_PATH="$ROOT/actions/refs-not-closing" \
+    bash "$ENTRYPOINT"
+}
+
+check "action boundary fails when GraphQL read fails" 42 \
+  "fake GraphQL read failed" action_boundary failure
+check "action boundary refuses a partial closing-reference page" 5 \
+  "refusing a partial verdict" action_boundary partial
+check "action boundary accepts a complete GraphQL read" 0 \
+  "no Refs target" action_boundary success
+
+one_graphql_read() {
+  [ "$(grep -c "gh api graphql" "$ENTRYPOINT")" -eq 1 ]
+  printf '1\n'
+}
+
+check "action performs exactly one GraphQL read" 0 "1" \
+  one_graphql_read
+check "composite delegates to the tested entrypoint" 0 "run.sh" \
+  grep -F "run: bash \"\$GITHUB_ACTION_PATH/run.sh\"" "$ACTION"
+
+check "workflow wakes on body edits" 0 "types: [opened, edited, reopened, synchronize]" \
+  grep -F "types: [opened, edited, reopened, synchronize]" "$WORKFLOW"
+check "workflow is pull_request-only" 1 "" \
+  grep -E '^  (push|pull_request_target|workflow_dispatch|schedule|issue_comment):' \
+  "$WORKFLOW"
+check "workflow grants read-only pull request access" 0 "pull-requests: read" \
+  grep -F "pull-requests: read" "$WORKFLOW"
+
+summary