fix(effort): harden lib/effort-pins.sh (security gate, 4 LOW)

Last map line without newline read; unclosed frontmatter skipped with an
err; level re-read after write, mismatch counted as failed; mktemp + cp -p
+ mv, temp removed on failure; rc 1 on any rejected or failed entry.
Cases T11-T14 in the fixture suite; contract criteria 8-9.

.claude/tasks/contracts/2026-09-29-effort-round-1315.md

@@ -12,6 +12,7 @@
 - Defect found in passing, fixed here: `update-all.sh` re-fetched the vendored skills but never re-applied the pins (lost until the next `make plugin`).
 - Defect found in passing, surfaced not fixed: ~94 % of sub-agent usage records carry no `output_tokens_details`, so `lib/effort-audit.py` read zero thinking on sub-agents; the script now prints coverage and a CAVEAT; EVAL-037's "executors stay cheap" is a measurement gap (registry correction pending user approval).
 - lib/tests/effort-routing.test.sh line 4 widens its shellcheck directive from SC2015 to SC2015,SC2016: the new `has … '$REPO'` locks are literal source text, the `$REPO` must NOT expand (authorized; a test file, informational). [verifier 2026-09-29 gap 3]
+- Hardening round (criteria 8-9) added after the security gate on user go; the fixture suite may `chmod` its own mktemp directory (555 then back to 755 for the trap cleanup), never `-R`, never outside the fixture.
 - Frontmatter placement of the inserted `effort:` line (after `name:`, else before the closing `---`) has no harness effect; locked by the fixture suite only.
 
 ## ACCEPTANCE CRITERIA
@@ -44,6 +45,15 @@
    EXPECT: LINT_OK
    EVIDENCE: MET exit=0 marker-found :: LINT_OK
 
+8. Hardening (security gate 2026-09-29, 4 LOW, user go): (a) a map whose last line has no trailing newline still applies that line; (b) a SKILL.md whose frontmatter has no closing `---` is skipped with an err line, file byte-identical; (c) a CRLF SKILL.md (`---\r`) is never counted as applied: the helper re-reads the level after the write and reports a mismatch as err, counted as failed (rc 1); (d) a write failure (read-only skill directory) is reported as err, counted as failed, and leaves no temporary file behind. Cases T11-T14 in lib/tests/effort-pins.test.sh, header comment of the helper updated.
+   CHECK: out=$(make test suite=lib/tests/effort-pins.test.sh 2>&1); echo "$out" | grep -q 'effort-pins: [0-9]* pass, 0 fail' || { echo "$out" | grep FAIL; exit 1; }; for k in T11-last-line-no-newline T12-unterminated-frontmatter-skipped T13-crlf-not-counted-applied T14-write-failure-no-temp; do echo "$out" | grep -q "PASS $k" || { echo "missing PASS $k"; exit 1; }; done; echo HARDEN_GREEN
+   EXPECT: HARDEN_GREEN
+   EVIDENCE: MET exit=0 marker-found :: HARDEN_GREEN
+9. Hardening keeps everything else green: shellcheck clean on the helper and its suite, effort-routing census green, live tree still idempotent (0 applied).
+   CHECK: shellcheck lib/effort-pins.sh lib/tests/effort-pins.test.sh && make test suite=lib/tests/effort-routing.test.sh 2>&1 | grep -q 'census: [0-9]* pass, 0 fail' && bash lib/effort-pins.sh 2>&1 | grep -q ' 0 applied, [0-9]* already at level' && echo HARDEN_STABLE
+   EXPECT: HARDEN_STABLE
+   EVIDENCE: MET exit=0 marker-found :: HARDEN_STABLE
+
 ## FILE SCOPE
 - lib/effort-pins.txt, lib/effort-pins.sh (new); lib/tests/effort-pins.test.sh (new); lib/tests/effort-routing.test.sh
 - install-plugins.sh, update-all.sh (re-apply call), lib/effort-audit.py (coverage)

lib/effort-pins.sh

@@ -6,12 +6,16 @@
 # it back after the last vendoring step of install-plugins.sh and
 # update-all.sh. Idempotent: same level → untouched, other level →
 # replaced inside the frontmatter only, skill not vendored → skipped,
-# malformed map line → rejected loudly, never applied. Placement inside the
+# malformed map line → rejected loudly, never applied. Four hardenings:
+# a map whose last line lacks a newline is still read; a SKILL.md whose
+# frontmatter never closes is skipped untouched; the level is re-read after
+# every write and a mismatch (CRLF, malformed) counts as failed; the write
+# goes through a mktemp sibling removed on any failure. Placement inside the
 # frontmatter has no effect on the harness, which reads the key anywhere.
 #
 # Usage: source it, then `apply_effort_pins [repo-root]`
 #        or standalone: bash lib/effort-pins.sh [repo-root]
-# Exit 1 when at least one map line was rejected.
+# Exit 1 when at least one map line was rejected or a skill failed.
 
 EFFORT_PINS_REPO="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 EFFORT_PIN_LEVEL_RE='^(low|medium|high|xhigh|max)$'
@@ -29,12 +33,19 @@ _effort_pin_current() {
     | sed -n 's/^effort: //p' | head -1
 }
 
+# _effort_pin_closed <skill-file> → rc 0 when the frontmatter has a closing ---
+_effort_pin_closed() {
+  awk 'NR==1&&/^---$/{p=1;next} p&&/^---$/{f=1;exit} END{exit !f}' "$1"
+}
+
 # _effort_pin_write <skill-file> <name> <level> — replace the frontmatter
 # `effort:` line, or insert one after `name: <name>` (before the closing
 # `---` when the frontmatter has no name line). Body lines never change.
+# Writes a mktemp sibling then renames; any failure leaves no temp behind.
 _effort_pin_write() {
-  local file="$1" name="$2" level="$3"
+  local file="$1" name="$2" level="$3" tmp
-  awk -v n="$name" -v lvl="$level" '
+  tmp="$(mktemp "$file.XXXXXX")" || return 1
+  cp -p "$file" "$tmp" && awk -v n="$name" -v lvl="$level" '
     NR==1 && /^---$/ { fm=1; print; next }
     fm && /^---$/ {
       if (!done) { print "effort: " lvl; done=1 }
@@ -43,16 +54,36 @@ _effort_pin_write() {
     fm && /^effort: / { if (!done) { print "effort: " lvl; done=1 }; next }
     fm && $0 == "name: " n { print; if (!done) { print "effort: " lvl; done=1 }; next }
     { print }
-  ' "$file" > "$file.tmp" && mv "$file.tmp" "$file"
+  ' "$file" > "$tmp" && mv "$tmp" "$file" && return 0
+  rm -f "$tmp"
+  return 1
+}
+
+# _effort_pin_apply_one <file> <name> <level> → rc 0 applied, 2 already at
+# level, 1 failed (err line printed, file untouched or write rolled back)
+_effort_pin_apply_one() {
+  local file="$1" name="$2" level="$3"
+  if ! _effort_pin_closed "$file"; then
+    err "effort-pins: $file: frontmatter never closed — skipped"; return 1
+  fi
+  [ "$(_effort_pin_current "$file")" = "$level" ] && return 2
+  if ! _effort_pin_write "$file" "$name" "$level"; then
+    err "effort-pins: $file: write failed"; return 1
+  fi
+  if [ "$(_effort_pin_current "$file")" != "$level" ]; then
+    err "effort-pins: $file: level not applied (CRLF or malformed frontmatter?)"
+    return 1
+  fi
+  return 0
 }
 
 # apply_effort_pins [repo-root] — walk the map, pin every vendored skill
 apply_effort_pins() {
-  local repo="${1:-$EFFORT_PINS_REPO}" map name level rest file
+  local repo="${1:-$EFFORT_PINS_REPO}" map name level rest file rc
-  local applied=0 kept=0 rejected=0
+  local applied=0 kept=0 rejected=0 failed=0
   map="$repo/lib/effort-pins.txt"
   [ -f "$map" ] || { err "effort-pins: map missing: $map"; return 1; }
-  while read -r name level rest; do
+  while read -r name level rest || [ -n "$name" ]; do
     case "$name" in ''|'#'*) continue ;; esac
     if [ -n "$rest" ] || ! [[ "$name" =~ $EFFORT_PIN_NAME_RE ]] \
        || ! [[ "$level" =~ $EFFORT_PIN_LEVEL_RE ]]; then
@@ -61,13 +92,15 @@ apply_effort_pins() {
     fi
     file="$repo/skills-external/$name/SKILL.md"
     [ -f "$file" ] || continue
-    if [ "$(_effort_pin_current "$file")" = "$level" ]; then
+    _effort_pin_apply_one "$file" "$name" "$level"; rc=$?
-      kept=$((kept + 1)); continue
+    case "$rc" in
-    fi
+      0) applied=$((applied + 1)) ;;
-    _effort_pin_write "$file" "$name" "$level" && applied=$((applied + 1))
+      2) kept=$((kept + 1)) ;;
+      *) failed=$((failed + 1)) ;;
+    esac
   done < "$map"
-  ok "effort-pins: $applied applied, $kept already at level"
+  ok "effort-pins: $applied applied, $kept already at level, $failed failed"
-  [ "$rejected" -eq 0 ]
+  [ "$rejected" -eq 0 ] && [ "$failed" -eq 0 ]
 }
 
 if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then

lib/tests/effort-pins.test.sh

@@ -5,7 +5,8 @@
 # skip a skill not vendored, insert before the closing `---` when the
 # frontmatter has no name line, run idempotently, reject a bad level, a
 # traversal name and a three-field line before writing anything, and
-# parse the real map without error. All on a throwaway fixture repo.
+# parse the real map without error; hardening: last map line without a
+# newline, unterminated frontmatter, CRLF file and read-only directory. All on a throwaway fixture repo.
 set -u
 ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
 LIB="$ROOT/lib/effort-pins.sh"
@@ -56,5 +57,35 @@ out="$(bash "$LIB" "$WORK/real" 2>&1)"; check T9-real-map-parses "$?" 0
 check T9b-real-map-nothing-applied "$(printf '%s' "$out" | grep -c '0 applied, 0 already')" 1
 check T10-missing-map-rc "$(bash "$LIB" "$WORK/nowhere" >/dev/null 2>&1; echo $?)" 1
 
+# hardening: each case in its own fixture repo
+mkrepo() { R="$WORK/$1"; mkdir -p "$R/lib" "$R/skills-external/$2"; }
+mkrepo h11 alpha; mkdir "$WORK/h11/skills-external/beta"
+printf -- '---\nname: alpha\n---\nb\n' > "$WORK/h11/skills-external/alpha/SKILL.md"
+printf -- '---\nname: beta\n---\nb\n' > "$WORK/h11/skills-external/beta/SKILL.md"
+printf 'alpha high\nbeta low' > "$WORK/h11/lib/effort-pins.txt"
+bash "$LIB" "$WORK/h11" >/dev/null 2>&1
+check T11-last-line-no-newline "$(fm_effort "$WORK/h11/skills-external/beta/SKILL.md")" low
+
+mkrepo h12 open; f12="$WORK/h12/skills-external/open/SKILL.md"
+printf -- '---\nname: open\nbody effort: max\n' > "$f12"; b12="$(cat "$f12")"
+printf 'open high\n' > "$WORK/h12/lib/effort-pins.txt"
+out="$(bash "$LIB" "$WORK/h12" 2>&1)"; rc=$?
+check T12-unterminated-frontmatter-skipped \
+  "$rc|$(cat "$f12" | cmp -s - <(printf '%s\n' "$b12") && echo same)|$(printf '%s' "$out" | grep -c "ERR .*$f12")" "1|same|1"
+
+mkrepo h13 crlf
+printf -- '---\r\nname: crlf\r\n---\r\nbody\r\n' > "$WORK/h13/skills-external/crlf/SKILL.md"
+printf 'crlf high\n' > "$WORK/h13/lib/effort-pins.txt"
+out="$(bash "$LIB" "$WORK/h13" 2>&1)"; rc=$?
+check T13-crlf-not-counted-applied \
+  "$rc|$(printf '%s' "$out" | grep -c 'ERR ')|$(printf '%s' "$out" | grep -c ' 0 applied, ')" "1|1|1"
+
+mkrepo h14 ro; d14="$WORK/h14/skills-external/ro"
+printf -- '---\nname: ro\n---\nb\n' > "$d14/SKILL.md"
+printf 'ro high\n' > "$WORK/h14/lib/effort-pins.txt"
+chmod 555 "$d14"; out="$(bash "$LIB" "$WORK/h14" 2>&1)"; rc=$?; chmod 755 "$d14"
+check T14-write-failure-no-temp \
+  "$rc|$(printf '%s' "$out" | grep -c 'ERR ')|$(find "$d14" -name 'SKILL.md.*' | wc -l)" "1|1|0"
+
 echo "effort-pins: $pass pass, $fail fail"
 [ "$fail" -eq 0 ]