test(hooks): pin the pre-task-ritual hook to its registration

Closes #44.

That issue overstated the risk and this corrects it. The hook is three lines
and echoes a string -- no bash-isms, so it cannot fail the way secret-guard
appeared to. The real exposure is narrower and duller: it can stop working
silently, and its entire job is to be visible.

THE ASSERTION THAT MATTERS IS REGISTRATION. A hook file that exists but is
absent from hooks.json does nothing at all and looks identical on disk to one
that works. So the test derives the command from hooks.json and runs it exactly
as registered, substituting CLAUDE_PLUGIN_ROOT the way the harness does, rather
than inventing its own invocation.

That choice is the lesson from #44's sibling. secret_guard_test.sh piped its
hook into `sh` while hooks.json runs it with `bash`; on Debian /bin/sh is dash,
which has no `set -o pipefail`, so the suite failed 20/20 in CI against a hook
that was FINE in production. The test was wrong, not the hook -- and the
earlier commit message for that fix said the shebang decides the interpreter,
which hooks.json shows is not true. Deriving the invocation removes the whole
class rather than fixing one instance of it.

No red phase to report: the hook was already correct, so this is regression
pinning, not TDD. Teeth proven by mutation against a throwaway copy instead:

  - hook runs but prints nothing      -> 6 failures
  - hook removed from hooks.json      -> caught, suite stops early
  - ONE ritual step dropped, rule 0
    still named                       -> caught (9 passed, 1 failed)

The third is the one worth having. Losing the whole line is obvious; quietly
losing "failing test" from the ritual while the banner still reads correctly is
the drift that would actually happen.

Bump-Type: patch

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.claude-plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "skills",
   "description": "Mathias's engineering skills library, plus the hooks and MCP servers that make it enforceable: TDD, clean code, debugging, specs, discovery, CI, and secret hygiene.",
-  "version": "0.19.0",
+  "version": "0.19.3",
   "author": {
     "name": "Mathias",
     "url": "https://git.d-ma.be/mathias"

Taskfile.yml

@@ -145,8 +145,13 @@ tasks:
         # not run (no jq, or no env-file — CI has neither); that is reported
         # and not fatal, but it is never treated as a pass.
         if [ -x "{{.TASKFILE_DIR}}/bin/check-mcp-env" ]; then
-          "{{.TASKFILE_DIR}}/bin/check-mcp-env" "{{.TASKFILE_DIR}}/.mcp.json" "$HOME/.op-env"
-          case $? in
+          # `|| rc=$?` is load-bearing, not style. Task runs this block under
+          # `sh -e`, so a bare invocation exiting non-zero kills the shell
+          # before `case` is reached -- the tolerance below never ran, and the
+          # gate died with `exit status 2` on the commit that added it.
+          rc=0
+          "{{.TASKFILE_DIR}}/bin/check-mcp-env" "{{.TASKFILE_DIR}}/.mcp.json" "$HOME/.op-env" || rc=$?
+          case $rc in
             0) ;;
             2) echo "NOTE: MCP env wiring unverified on this host" >&2 ;;
             *) fail=1 ;;

bin/check-mcp-env

@@ -41,7 +41,17 @@ if [ ! -f "$CONFIG" ]; then
 fi
 
 if [ ! -f "$ENVFILE" ]; then
+  # EXPECTED IN CI, and permanently so. The env-file holds live credentials, so
+  # it is not on the runner and must not be -- which means this check can only
+  # ever verify on a host that has one. infra#368 added jq to the runner image
+  # believing that would let CI verify; it removed the jq branch below and
+  # changed nothing else, because this branch is the binding one.
+  #
+  # Said plainly so nobody concludes CI covers this. It does not, it cannot,
+  # and putting ~/.op-env on the runner to make it would be trading a real
+  # secret for a green tick.
   echo "ERROR: no such env-file: $ENVFILE -- cannot verify MCP variables" >&2
+  echo "       (expected in CI: this check only verifies on a host with ~/.op-env)" >&2
   exit 2
 fi
 

tests/check_tolerates_unverifiable_test.sh

@@ -0,0 +1,70 @@
+#!/bin/sh
+# `task check` must survive a check that reports "could not verify".
+#
+# The regression these exist for: bin/check-mcp-env exits 2 to mean "I could
+# not run — no jq, or no env-file", which the gate deliberately treats as a
+# reported NOTE rather than a failure. The Taskfile said exactly that:
+#
+#   "$DIR/check-mcp-env" "$DIR/.mcp.json" "$HOME/.op-env"
+#   case $? in 0) ;; 2) echo "NOTE: ..." ;; *) fail=1 ;; esac
+#
+# and it did not work. Task runs each cmds block under `sh -e`, so a bare
+# command exiting non-zero aborts the shell *before* `case $?` is ever
+# reached. The whole gate died with `exit status 2`. Locally the check found
+# jq and exited 0, so it went green; CI has neither jq nor ~/.op-env, so main
+# went red on the very commit that added it (skills run #57, 2026-09-07).
+#
+# A tolerated exit code that is only tolerated on the host where it never
+# fires is not tolerated at all. This pins the tolerance itself.
+#
+# No mocking: pointing HOME at an empty directory removes ~/.op-env, which is
+# exactly the condition CI runs under, so check-mcp-env genuinely exits 2.
+
+set -u
+
+ROOT=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+
+pass=0
+fail=0
+
+ok() { pass=$((pass + 1)); printf '  ok   %s\n' "$1"; }
+no() { fail=$((fail + 1)); printf '  FAIL %s\n' "$1"; }
+
+if ! command -v task >/dev/null 2>&1; then
+  printf '  SKIP: task not installed -- cannot exercise the gate\n'
+  exit 0
+fi
+
+TMP=$(mktemp -d)
+trap 'rm -rf "$TMP"' EXIT
+
+# Sanity: the precondition must actually hold, or the test proves nothing.
+# An empty HOME means no ~/.op-env, so check-mcp-env cannot verify anything.
+"$ROOT/bin/check-mcp-env" "$ROOT/.mcp.json" "$TMP/.op-env" >/dev/null 2>&1
+rc=$?
+if [ "$rc" -eq 2 ]; then
+  ok 'precondition: check-mcp-env exits 2 when the env-file is absent'
+else
+  no "precondition: expected check-mcp-env to exit 2, got $rc"
+fi
+
+# The assertion. `task check` must still pass, and must say why it could not
+# verify -- silence would mean the check was skipped rather than tolerated.
+out=$(HOME="$TMP" task --dir "$ROOT" check 2>&1)
+rc=$?
+
+if [ "$rc" -eq 0 ]; then
+  ok 'task check passes when MCP env wiring cannot be verified'
+else
+  no "task check exited $rc when check-mcp-env reported unverifiable"
+  printf '%s\n' "$out" | sed 's/^/       | /' | tail -8
+fi
+
+if printf '%s' "$out" | grep -q 'unverified'; then
+  ok 'the unverifiable check is reported, not silently skipped'
+else
+  no 'no NOTE reported -- an unverifiable check must never look like a pass'
+fi
+
+printf '  %d passed, %d failed\n' "$pass" "$fail"
+[ "$fail" -eq 0 ]

tests/pre_task_ritual_test.sh

@@ -0,0 +1,103 @@
+#!/bin/sh
+# Tests for hooks/pre-task-ritual.sh — the UserPromptSubmit hook that surfaces
+# rule 0 on every prompt (#44).
+#
+# WHY THIS EXISTS, AND WHAT IT DELIBERATELY DOES NOT CLAIM
+# This hook is three lines and echoes a string. It has no bash-isms, so it
+# cannot fail the way secret-guard appeared to; that risk was overstated when
+# this test was requested. What it CAN do is stop working silently, and its
+# whole job is to be visible -- if the text stops appearing, rule 0 stops being
+# surfaced on every prompt and nothing announces that.
+#
+# THE ASSERTION THAT MATTERS IS REGISTRATION.
+# A hook file that exists but is not in hooks.json does absolutely nothing, and
+# looks identical on disk to one that works. So this derives the command from
+# hooks.json rather than assuming one: the registration is the source of truth
+# for how the hook is invoked, and a test that invokes it its own way is
+# testing something the harness never runs.
+#
+# That distinction is not hypothetical. secret_guard_test.sh piped its hook into
+# `sh` while hooks.json runs it with `bash`; on Debian /bin/sh is dash, which
+# has no `set -o pipefail`, and the suite failed 20/20 in CI against a hook that
+# was fine in production. The test was wrong, not the hook. Deriving the
+# invocation removes the opportunity for that class of mistake entirely.
+
+set -u
+
+ROOT=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+HOOK="$ROOT/hooks/pre-task-ritual.sh"
+REG="$ROOT/hooks/hooks.json"
+
+pass=0
+fail=0
+ok() { pass=$((pass + 1)); printf '  ok   %s\n' "$1"; }
+no() { fail=$((fail + 1)); printf '  FAIL %s\n' "$1"; }
+
+if ! command -v jq >/dev/null 2>&1; then
+  printf '  SKIP: jq not installed -- cannot read the hook registration\n'
+  exit 0
+fi
+
+[ -f "$HOOK" ] || { printf '  FAIL %s does not exist\n' "$HOOK"; exit 1; }
+ok 'hook file exists'
+
+[ -f "$REG" ] || { printf '  FAIL %s does not exist\n' "$REG"; exit 1; }
+
+# 1. Registered, and on the right event. UserPromptSubmit is what makes it fire
+#    on every prompt; registered under any other event it would still "exist"
+#    and still do nothing useful.
+CMD=$(jq -r '
+  .hooks.UserPromptSubmit[]?.hooks[]?
+  | select(.command | test("pre-task-ritual"))
+  | .command
+' "$REG" 2>/dev/null | head -1)
+
+if [ -n "$CMD" ]; then
+  ok 'registered on UserPromptSubmit in hooks.json'
+else
+  no 'not registered on UserPromptSubmit -- the file would exist and never run'
+  printf '  %d passed, %d failed\n' "$pass" "$fail"
+  exit 1
+fi
+
+# 2. Run it EXACTLY as registered, with the harness variable substituted the way
+#    the harness substitutes it.
+OUT=$(CLAUDE_PLUGIN_ROOT="$ROOT" sh -c "$CMD" 2>&1)
+rc=$?
+
+[ "$rc" -eq 0 ] && ok 'exits 0 as registered' \
+  || no "exited $rc -- a non-zero UserPromptSubmit hook can block the prompt"
+
+# 3. The content is the point. A hook that runs and says nothing is the same as
+#    no hook, and that is the failure this pins.
+if [ -n "$OUT" ]; then
+  ok 'produces output'
+else
+  no 'produced no output -- rule 0 would silently stop being surfaced'
+fi
+
+case "$OUT" in
+  *"Rule 0"*) ok 'names rule 0' ;;
+  *)          no "does not name rule 0: '$OUT'" ;;
+esac
+
+# Each of the four steps, individually. Naming rule 0 while having quietly lost
+# a step is the plausible drift, not losing the whole line.
+for step in brain_query skill 'failing test' 'success criterion'; do
+  case "$OUT" in
+    *"$step"*) ok "states the '$step' step" ;;
+    *)         no "lost the '$step' step from the ritual" ;;
+  esac
+done
+
+# 4. The interpreter named in the registration must actually exist, or the hook
+#    fails on that host with a message nobody reads.
+INTERP=${CMD%% *}
+if command -v "$INTERP" >/dev/null 2>&1; then
+  ok "registered interpreter '$INTERP' is available"
+else
+  no "registered interpreter '$INTERP' not found on this host"
+fi
+
+printf '  %d passed, %d failed\n' "$pass" "$fail"
+[ "$fail" -eq 0 ]

tests/secret_guard_test.sh

@@ -24,7 +24,7 @@ decision_for() {
   _tool=${2:-Bash}
   jq -n --arg t "$_tool" --arg c "$_cmd" \
     '{tool_name: $t, tool_input: {command: $c}}' \
-    | sh "$GUARD" \
+    | "$GUARD" \
     | jq -r '.hookSpecificOutput.permissionDecision // "MISSING"'
 }
 
@@ -42,6 +42,20 @@ expect() {
   fi
 }
 
+# Invoked as a PROGRAM above, never as `sh "$GUARD"`. Claude Code executes the
+# hook directly, so its `#!/usr/bin/env bash` shebang decides the interpreter;
+# piping it into `sh` overrides that and tests something production never runs.
+#
+# It is not academic. On Debian /bin/sh is dash, which has no `set -o
+# pipefail`, so the guard died on line 23 before reading a byte of input and
+# every deny case returned empty -- 20 of 20 assertions failed in CI while
+# passing on a host where /bin/sh happens to be bash. A security gate that
+# tests green and cannot start is the worst of both.
+if [ ! -x "$GUARD" ]; then
+  printf 'FAIL: %s is not executable -- it must run via its own shebang\n' "$GUARD"
+  exit 1
+fi
+
 if [ ! -f "$GUARD" ]; then
   printf 'FAIL: %s does not exist\n' "$GUARD"
   exit 1