feat(doctor): report golangci-lint built with a Go older than GOROOT

Second recurrence of the same host fault (infra#375; first hit
openbanking-api 2026-09-03, then cobalt-dingo 2026-09-08). golangci-lint
embeds the go/types export-data reader from the Go it was BUILT with, so a
newer GOROOT makes it unable to decode the stdlib:

  panic: file requires newer Go version go1.27 (application built with go1.26)

An earlier form printed a typecheck error naming the user's own source file,
which sends people to debug code that is fine. It cost time in two repos before
anyone recognised it as a host fault rather than a repo fault.

CI never sees it — the runner image has matching versions — so it breaks
exactly the local `task check` that AGENT.md requires before every push, and
nothing else. The fix was always one reinstall; the missing thing was the
signal, which is what doctor is for.

Fails open by design: an unparseable version, or no Go at all, is a normal host
and not a fault doctor may assert. Version comparison is major.minor in POSIX
sh rather than sort -V, since this runs on macOS too and the export-data format
is minor-versioned.

Also makes the suite hermetic. The check reads the real host, so on a machine
whose golangci-lint is genuinely stale every unrelated fixture started failing.
The harness now prepends a matching fake pair for the whole file, and only the
four cases that opt in exercise the check.

Verified against koala, which is currently in exactly this state:

  FAIL toolchain: golangci-lint built with go1.26.1 but GOROOT is go1.27.0
       — lint panics on every Go repo; reinstall it under the current
       toolchain (infra#375)

doctor: 25 passed, 0 failed. Full suite green.

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": "0.18.0",
+  "version": "0.19.4",
   "author": {
     "name": "Mathias",
     "url": "https://git.d-ma.be/mathias"

.mcp.json

@@ -1,5 +1,5 @@
 {
-  "_comment": "Tailscale Serve on koala, not the public d-ma.be hostnames. The public path exits to Cloudflare and NPM to reach a k3s service on the same machine most sessions run on, which imposes rate limits and message-size caps on tool results. Serve terminates TLS with a real Tailscale cert and proxies to the NodePort over loopback, so traffic reaches the service from koala itself and satisfies the default-deny-ingress NetworkPolicy with no cluster change. Clients need 'tailscale set --accept-dns=true' for the MagicDNS name to resolve; see mathias/skills#24.",
+  "_comment": "Tailscale Serve on koala, not the public d-ma.be hostnames. The public path exits to Cloudflare and NPM to reach a k3s service on the same machine most sessions run on, which imposes rate limits and message-size caps on tool results. Serve terminates TLS with a real Tailscale cert and proxies to the NodePort over loopback, so traffic reaches the service from koala itself and satisfies the default-deny-ingress NetworkPolicy with no cluster change. Clients need 'tailscale set --accept-dns=true' for the MagicDNS name to resolve; see mathias/skills#24. Every ${VAR} below must be one ~/.op-env defines -- bin/check-mcp-env enforces that, because an undefined one sends an empty Authorization header and reports as 'requires authentication', which is indistinguishable from a revoked credential.",
   "mcpServers": {
     "brain": {
       "type": "http",
@@ -11,23 +11,24 @@
     "infra": {
       "type": "http",
       "url": "https://koala.tail30472e.ts.net:8444/mcp"
+    },
+    "gitea": {
+      "_comment": "gitea-mcp authenticates by PASS-THROUGH: the bearer is a Gitea PAT, which the server validates against Gitea and then acts as. So no dedicated MCP token is needed, and the AgentSecrets blocker that parked this entry (skills#32, #33) never applied to it -- DMABE_GITEA_API_TOKEN is op://HomeLab and already in the session environment. Verified 2026-09-07: initialize 200 (serverInfo gitea-mcp) and tools/list returns 41 tools. Two DIFFERENT PATs both authenticate while GITEA_MCP_TOKEN 401s, which is what proves this is pass-through validation and not a static-token comparison.",
+      "type": "http",
+      "url": "https://koala.tail30472e.ts.net:8446/mcp",
+      "headers": {
+        "Authorization": "Bearer ${DMABE_GITEA_API_TOKEN}"
+      }
     }
   },
   "_parked": {
-    "_reason": "cad and gitea-mcp are proxied, reachable and AUTHENTICATING: tailscale serve 8445 -> 127.0.0.1:31877 and 8446 -> 127.0.0.1:30340; an MCP initialize with the correct bearer returns 200 from both (serverInfo gitea-mcp 0.1.0, cad aed2aaf). They stay parked only because nothing puts those two tokens into the session environment. Both live in the 1Password AgentSecrets vault, and by deliberate design (infra#224, closed) no single identity on koala reads both vaults: koala-homelab is HomeLab-only and resolves ~/.op-env, koala-agentsecrets-write is AgentSecrets-only and lives in ~/.op-agent-write.env. Adding an AgentSecrets reference to ~/.op-env does NOT degrade gracefully -- `op run` fails wholesale and every other token, BRAIN_MCP_TOKEN included, goes unresolved with it. Enabling needs a read-scoped AgentSecrets identity in the session-env path; see mathias/skills#32, #33.",
+    "_reason": "cad is proxied, reachable and AUTHENTICATING: tailscale serve 8445 -> 127.0.0.1:31877, and an MCP initialize with the correct bearer returns 200 (serverInfo cad aed2aaf). It stays parked only because nothing puts CAD_MCP_TOKEN into the session environment. It lives in the 1Password AgentSecrets vault, and by deliberate design (infra#224, closed) no single identity on koala reads both vaults: koala-homelab is HomeLab-only and resolves ~/.op-env, koala-agentsecrets-write is AgentSecrets-only and lives in ~/.op-agent-write.env. Adding an AgentSecrets reference to ~/.op-env does NOT degrade gracefully -- `op run` fails wholesale and every other token, BRAIN_MCP_TOKEN included, goes unresolved with it. Enabling needs a read-scoped AgentSecrets identity in the session-env path; see mathias/skills#32, #33. gitea was parked here for the same stated reason and has been unparked: it needs no AgentSecrets token at all, because gitea-mcp is pass-through-authenticated.",
     "cad": {
       "type": "http",
       "url": "https://koala.tail30472e.ts.net:8445/mcp",
       "headers": {
         "Authorization": "Bearer ${CAD_MCP_TOKEN}"
       }
-    },
-    "gitea": {
-      "type": "http",
-      "url": "https://koala.tail30472e.ts.net:8446/mcp",
-      "headers": {
-        "Authorization": "Bearer ${GITEA_MCP_STATIC_TOKEN}"
-      }
     }
   }
 }

Taskfile.yml

@@ -138,6 +138,26 @@ tasks:
           echo "ERROR: missing .claude-plugin/plugin.json" >&2; fail=1
         fi
 
+        # Every ${VAR} a live .mcp.json server interpolates must be one the
+        # session env-file defines. An undefined one is silent: the header
+        # goes out empty and the server reports "requires authentication",
+        # which reads as a revoked credential. Exit 2 means the check could
+        # not run (no jq, or no env-file — CI has neither); that is reported
+        # and not fatal, but it is never treated as a pass.
+        if [ -x "{{.TASKFILE_DIR}}/bin/check-mcp-env" ]; then
+          # `|| rc=$?` 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 ;;
+          esac
+        fi
+
         if [ $fail -ne 0 ]; then
           echo "check FAILED" >&2; exit 1
         fi

bin/check-mcp-env

@@ -0,0 +1,99 @@
+#!/bin/sh
+# check-mcp-env — assert every variable a live MCP server interpolates is one
+# the session env-file actually defines.
+#
+# Why this is a gate and not a comment: the failure is silent. A header of
+# "Bearer ${FOO}" where FOO is undefined does not error -- it goes out empty,
+# the server answers 401, and Claude Code reports "requires authentication",
+# which reads exactly like a revoked credential. On 2026-09-07 that cost a
+# full investigation on koala before the credential turned out to be fine.
+#
+# Servers under `_parked` are exempt by design. Parked means "reachable, but
+# nothing puts its token in the environment yet" -- flagging those would
+# report the intended state as a fault.
+#
+# Usage:  check-mcp-env <mcp.json> <env-file>
+#
+# Exit 0  every live server's variables are defined
+#      1  at least one is not, named on stderr
+#      2  could not verify (bad usage, unreadable input, jq absent).
+#         Deliberately distinct from 0: an unverified config is not a clean
+#         one, and a gate that cannot run should say so rather than pass.
+
+set -u
+
+CONFIG=${1:-}
+ENVFILE=${2:-}
+
+if [ -z "$CONFIG" ] || [ -z "$ENVFILE" ]; then
+  echo "usage: check-mcp-env <mcp.json> <env-file>" >&2
+  exit 2
+fi
+
+if ! command -v jq >/dev/null 2>&1; then
+  echo "SKIP: jq not installed -- MCP env wiring unverified" >&2
+  exit 2
+fi
+
+if [ ! -f "$CONFIG" ]; then
+  echo "ERROR: no such config: $CONFIG" >&2
+  exit 2
+fi
+
+if [ ! -f "$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: $ENVFILE -- cannot verify MCP variables" >&2
+  echo "       (expected in CI: this check only verifies on a host with ~/.op-env)" >&2
+  exit 2
+fi
+
+# Every "<server>\t<VAR>" pair a live server interpolates. `..` walks the whole
+# value, so a variable is found wherever it is placed, not only under headers.
+refs=$(jq -r '
+  .mcpServers // {}
+  | to_entries[]
+  | .key as $server
+  | (.value | .. | strings)
+  | select(test("\\$\\{"))
+  | [ scan("\\$\\{([A-Za-z_][A-Za-z0-9_]*)\\}")[] ]
+  | .[]
+  | "\($server)\t\(.)"
+' "$CONFIG" 2>/dev/null) || {
+  echo "ERROR: $CONFIG is not valid JSON -- MCP env wiring unverified" >&2
+  exit 2
+}
+
+if [ -z "$refs" ]; then
+  echo "check-mcp-env: no interpolated variables in live servers"
+  exit 0
+fi
+
+fail=0
+checked=0
+for pair in $(printf '%s\n' "$refs" | tr '\t' ':'); do
+  server=${pair%%:*}
+  var=${pair#*:}
+  checked=$((checked + 1))
+  if grep -qE "^[[:space:]]*(export[[:space:]]+)?$var=" "$ENVFILE"; then
+    continue
+  fi
+  printf 'ERROR: MCP server %s interpolates %s, which %s does not define.\n' \
+    "$server" "$var" "$ENVFILE" >&2
+  printf '       It will send an empty Authorization header and report as "requires authentication".\n' >&2
+  fail=1
+done
+
+if [ "$fail" -ne 0 ]; then
+  exit 1
+fi
+
+printf 'check-mcp-env: %d interpolated variable(s) across live MCP servers, all defined in %s\n' \
+  "$checked" "$ENVFILE"

bin/doctor

@@ -327,6 +327,44 @@ if [ "$ONLINE" -eq 1 ]; then
   fi
 fi
 
+# --- toolchain: golangci-lint must be built with Go >= GOROOT ---------------
+# infra#375, second recurrence. golangci-lint embeds the go/types export-data
+# reader from the Go it was BUILT with. When GOROOT is newer, that reader
+# cannot decode the stdlib and the linter dies:
+#
+#   panic: file requires newer Go version go1.27 (application built with go1.26)
+#
+# An earlier form printed a typecheck error naming the user's own file, which
+# sends people to debug code that is fine. It cost time in two repos before
+# anyone recognised it as a host fault rather than a repo fault.
+#
+# It is invisible to CI -- the runner image has matching versions -- so it
+# breaks exactly the local `task check` that AGENT.md requires before a push,
+# and nothing else. That is why it belongs in doctor: the signal was missing,
+# not the fix.
+#
+# Fails open on anything unparseable. A host with no Go toolchain is a normal
+# host, not a broken one, and doctor runs in a SessionStart hook everywhere.
+ver_lt() {
+  # 0 when $1 < $2 on major.minor. Deliberately not sort -V: this is POSIX sh
+  # that also runs on macOS, and the export-data format is minor-versioned, so
+  # patch level does not enter into it.
+  _a=${1%%.*}; _ar=${1#*.}; _am=${_ar%%.*}
+  _b=${2%%.*}; _br=${2#*.}; _bm=${_br%%.*}
+  case "$_a$_am$_b$_bm" in *[!0-9]*) return 1 ;; esac
+  [ "$_a" -lt "$_b" ] && return 0
+  [ "$_a" -gt "$_b" ] && return 1
+  [ "$_am" -lt "$_bm" ]
+}
+
+if command -v golangci-lint >/dev/null 2>&1 && command -v go >/dev/null 2>&1; then
+  lint_go=$(golangci-lint --version 2>/dev/null | sed -n 's/.*built with go\([0-9][0-9.]*\).*/\1/p' | head -1)
+  root_go=$(go version 2>/dev/null | sed -n 's/.*go version go\([0-9][0-9.]*\).*/\1/p' | head -1)
+  if [ -n "$lint_go" ] && [ -n "$root_go" ] && ver_lt "$lint_go" "$root_go"; then
+    add FAIL toolchain "golangci-lint built with go$lint_go but GOROOT is go$root_go — lint panics on every Go repo; reinstall it under the current toolchain (infra#375)"
+  fi
+fi
+
 # --- output -----------------------------------------------------------------
 if [ "$JSON" -eq 1 ]; then
   printf '{"checkout":"%s","expected":%s,"plugin":{"installed":"%s","available":"%s"},"findings":[%s]}\n' \

skills/adr/SKILL.md

@@ -58,8 +58,8 @@ adr:           0004
 title:         <the decision, as a sentence — not "database choice">
 status:        proposed | accepted | superseded | amended
 date:          2026-08-29
-deciders:      <who accepted it, by name — or "pending: <name>" while proposed>
-supersedes:    <adr number, or ->
+deciders:      <who accepted it, by name — or "pending: <name>" (QUOTED) while proposed>
+supersedes:    <adr number, or null>
 ---
 
 # ADR-0004 — <same title>
@@ -97,6 +97,25 @@ the condition that fires a revisit. An ADR with no validation section is a prefe
 with a template around it.
 ```
 
+### The frontmatter must actually parse
+
+It exists to be machine-read, so a block that does not load is worse than no block at
+all: it drops that ADR silently out of every "what is still open?" query, while looking
+correct. Two shapes this template used to suggest are invalid YAML, and both were found
+live in the estate on 2026-09-05 — `openbanking-api` ADR-0001 and `infra` ADR-0019, each
+copied verbatim from here:
+
+| Wrong | Why | Right |
+|---|---|---|
+| `supersedes:    -` | a bare dash is a YAML *sequence entry*, not a string | `supersedes:    null` |
+| `deciders:      pending: Mathias` | the second, unquoted colon reads as a nested mapping | `deciders:      "pending: Mathias"` |
+
+Check before committing:
+
+```sh
+python3 -c "import yaml,sys;yaml.safe_load(open(sys.argv[1]).read().split('---')[1]);print('ok')" docs/adr/0004-*.md
+```
+
 ## Preserving a productive tension
 
 Some tradeoffs are not unresolved because nobody thought hard enough. They are

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/doctor_test.sh

@@ -24,6 +24,18 @@ if [ ! -f "$DOCTOR" ]; then
   exit 1
 fi
 
+# The toolchain check (golangci-lint build-Go vs GOROOT) reads the real host
+# unless we say otherwise, which made every unrelated fixture fail on a machine
+# whose golangci-lint is genuinely stale. Give the whole suite a matching fake
+# pair so only the cases that OPT IN exercise that check.
+STUB_BIN="$WORK/_stub_bin"
+mkdir -p "$STUB_BIN"
+printf '#!/bin/sh\nprintf "golangci-lint has version 2.0.0 built with go1.27.0 from abc\\n"\n' > "$STUB_BIN/golangci-lint"
+printf '#!/bin/sh\ncase "$1" in version) printf "go version go1.27.0 linux/amd64\\n";; *) printf "\\n";; esac\n' > "$STUB_BIN/go"
+chmod +x "$STUB_BIN/golangci-lint" "$STUB_BIN/go"
+PATH="$STUB_BIN:$PATH"
+export PATH
+
 cleanup() { rm -rf "$WORK"; }
 trap cleanup EXIT INT TERM
 
@@ -291,5 +303,75 @@ else
   fail=$((fail + 1)); printf '  FAIL --online reports an unreachable remote as its own fault\n       rc=%s got: %s\n' "$_rc" "$_out"
 fi
 
+# --- toolchain: golangci-lint must be built with Go >= GOROOT ---------------
+# Measured on koala 2026-09-08 (infra#375, second recurrence): golangci-lint
+# 2.11.4 built with go1.26.1 against a go1.27.0 GOROOT PANICS on any Go repo --
+#
+#   panic: file requires newer Go version go1.27 (application built with go1.26)
+#
+# and the earlier form of the same fault printed a typecheck error naming YOUR
+# file, so the natural response is to debug code that is fine. It cost time in
+# two repos. CI never sees it (the runner image matches), so it breaks only the
+# local `task check` that AGENT.md requires before every push.
+#
+# The fixtures inject fake `go` and `golangci-lint` on PATH; nothing here reads
+# the real host toolchain, so the suite still passes on a machine without Go.
+mk_toolchain() { # $1=fixture  $2=lint-build-go  $3=goroot-go   ("" = absent)
+  _b="$1/bin"; mkdir -p "$_b"
+  if [ -n "$2" ]; then
+    printf '#!/bin/sh\nprintf "golangci-lint has version 2.11.4 built with %s from abc on 2026-01-01\\n"\n' "$2" > "$_b/golangci-lint"
+    chmod +x "$_b/golangci-lint"
+  fi
+  if [ -n "$3" ]; then
+    printf '#!/bin/sh\ncase "$1" in version) printf "go version %s linux/amd64\\n";; *) printf "\\n";; esac\n' "$3" > "$_b/go"
+    chmod +x "$_b/go"
+  fi
+  printf '%s' "$_b"
+}
+
+f=$(new_fixture golangci_old); wire_clean "$f"
+b=$(mk_toolchain "$f" go1.26.1 go1.27.0)
+_out=$(PATH="$b:$PATH" HOME="$f/home" DOCTOR_CHECKOUT="$f/ck" "$DOCTOR" 2>&1); _rc=$?
+if [ "$_rc" -ne 0 ] && printf '%s' "$_out" | grep -qi 'golangci'; then
+  pass=$((pass + 1)); printf '  ok   golangci-lint older than GOROOT is reported\n'
+else
+  fail=$((fail + 1)); printf '  FAIL golangci-lint older than GOROOT is reported\n       rc=%s got: %s\n' "$_rc" "$_out"
+fi
+
+# Matching versions are the normal case and must stay silent.
+f=$(new_fixture golangci_ok); wire_clean "$f"
+b=$(mk_toolchain "$f" go1.27.0 go1.27.0)
+_out=$(PATH="$b:$PATH" HOME="$f/home" DOCTOR_CHECKOUT="$f/ck" "$DOCTOR" 2>&1); _rc=$?
+if [ "$_rc" -eq 0 ]; then
+  pass=$((pass + 1)); printf '  ok   golangci-lint matching GOROOT is silent\n'
+else
+  fail=$((fail + 1)); printf '  FAIL golangci-lint matching GOROOT is silent\n       rc=%s got: %s\n' "$_rc" "$_out"
+fi
+
+# A NEWER lint than GOROOT is fine -- the constraint is one-directional.
+f=$(new_fixture golangci_newer); wire_clean "$f"
+b=$(mk_toolchain "$f" go1.28.0 go1.27.0)
+_out=$(PATH="$b:$PATH" HOME="$f/home" DOCTOR_CHECKOUT="$f/ck" "$DOCTOR" 2>&1); _rc=$?
+if [ "$_rc" -eq 0 ]; then
+  pass=$((pass + 1)); printf '  ok   golangci-lint newer than GOROOT is not a fault\n'
+else
+  fail=$((fail + 1)); printf '  FAIL golangci-lint newer than GOROOT is not a fault\n       rc=%s got: %s\n' "$_rc" "$_out"
+fi
+
+# Fail OPEN on anything unparseable. doctor runs in a SessionStart hook on every
+# machine; a toolchain it cannot read is not a fault it may assert. (A host with
+# no Go at all takes the same path -- command -v simply misses.)
+f=$(new_fixture golangci_garbled); wire_clean "$f"
+_b="$f/bin"; mkdir -p "$_b"
+printf '#!/bin/sh\nprintf "golangci-lint dev build\\n"\n' > "$_b/golangci-lint"
+printf '#!/bin/sh\nprintf "go version devel\\n"\n' > "$_b/go"
+chmod +x "$_b/golangci-lint" "$_b/go"
+_out=$(PATH="$_b:$PATH" HOME="$f/home" DOCTOR_CHECKOUT="$f/ck" "$DOCTOR" 2>&1); _rc=$?
+if [ "$_rc" -eq 0 ]; then
+  pass=$((pass + 1)); printf '  ok   an unreadable toolchain version is not asserted as a fault\n'
+else
+  fail=$((fail + 1)); printf '  FAIL an unreadable toolchain version is not asserted as a fault\n       rc=%s got: %s\n' "$_rc" "$_out"
+fi
+
 printf '\ndoctor: %d passed, %d failed\n' "$pass" "$fail"
 [ "$fail" -eq 0 ]

tests/mcp_config_test.sh

@@ -0,0 +1,118 @@
+#!/bin/sh
+# Tests for bin/check-mcp-env.
+#
+# The fault this gate exists for is silent, which is why it needs a gate at
+# all. An `.mcp.json` server whose Authorization header interpolates a
+# variable nothing in the session environment defines does not error: the
+# header goes out empty, the server answers 401, and Claude Code reports
+# "requires authentication". That is indistinguishable from a revoked or
+# expired credential, and on 2026-09-07 it cost a full investigation on koala
+# to establish that the credential was fine and the variable was simply never
+# set.
+#
+# So the property is: every ${VAR} a LIVE server interpolates must be a
+# variable the session env-file actually defines.
+#
+# The `_parked` block is deliberately exempt. Parked servers reference
+# variables nothing provides on purpose -- that is what parked means -- and a
+# gate that flagged them would be reporting the intended state as a fault.
+#
+# Fixtures drive the checker through argv, so no test touches the real host.
+
+set -u
+
+ROOT=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
+CHECK="$ROOT/bin/check-mcp-env"
+
+pass=0
+fail=0
+WORK=${TMPDIR:-/tmp}/mcp_config_test.$$
+
+if [ ! -f "$CHECK" ]; then
+  printf 'FAIL: %s does not exist\n' "$CHECK"
+  exit 1
+fi
+
+cleanup() { rm -rf "$WORK"; }
+trap cleanup EXIT INT TERM
+mkdir -p "$WORK"
+
+if ! command -v jq >/dev/null 2>&1; then
+  printf 'SKIP: jq not installed -- bin/check-mcp-env cannot be exercised\n'
+  exit 0
+fi
+
+# ok <name> / bad <name> <detail>
+ok()  { pass=$((pass+1)); printf '  ok   %s\n' "$1"; }
+bad() { fail=$((fail+1)); printf '  FAIL %s  %s\n' "$1" "${2:-}"; }
+
+# run <mcp-json> <env-file> -> sets $rc and $out
+run() {
+  out=$("$CHECK" "$1" "$2" 2>&1); rc=$?
+}
+
+ENVFILE="$WORK/op-env"
+cat > "$ENVFILE" <<'ENVEOF'
+BRAIN_MCP_TOKEN=op://HomeLab/brain/token
+DMABE_GITEA_API_TOKEN=op://HomeLab/gitea/token
+ENVEOF
+
+# --- a live server whose variable IS defined ---------------------------------
+cat > "$WORK/good.json" <<'JSONEOF'
+{"mcpServers":{"brain":{"type":"http","url":"https://x/mcp",
+ "headers":{"Authorization":"Bearer ${BRAIN_MCP_TOKEN}"}}}}
+JSONEOF
+run "$WORK/good.json" "$ENVFILE"
+[ "$rc" -eq 0 ] && ok "defined variable passes" || bad "defined variable passes" "rc=$rc $out"
+
+# --- a live server whose variable is NOT defined ------------------------------
+# The exact shape that broke: the server looks correct and fails at runtime.
+cat > "$WORK/missing.json" <<'JSONEOF'
+{"mcpServers":{"gitea":{"type":"http","url":"https://x/mcp",
+ "headers":{"Authorization":"Bearer ${GITEA_MCP_STATIC_TOKEN}"}}}}
+JSONEOF
+run "$WORK/missing.json" "$ENVFILE"
+if [ "$rc" -ne 0 ]; then
+  case "$out" in
+    *gitea*GITEA_MCP_STATIC_TOKEN*) ok "undefined variable is flagged, naming server and variable" ;;
+    *) bad "undefined variable is flagged, naming server and variable" "report did not name both: $out" ;;
+  esac
+else
+  bad "undefined variable is flagged, naming server and variable" "rc=0"
+fi
+
+# --- a server with no headers at all (the `infra` shape) ----------------------
+# Unauthenticated by design. Nothing to resolve, so nothing to flag.
+cat > "$WORK/noauth.json" <<'JSONEOF'
+{"mcpServers":{"infra":{"type":"http","url":"https://x/mcp"}}}
+JSONEOF
+run "$WORK/noauth.json" "$ENVFILE"
+[ "$rc" -eq 0 ] && ok "header-less server is not flagged" || bad "header-less server is not flagged" "rc=$rc $out"
+
+# --- parked servers are exempt ------------------------------------------------
+cat > "$WORK/parked.json" <<'JSONEOF'
+{"mcpServers":{"brain":{"type":"http","url":"https://x/mcp",
+  "headers":{"Authorization":"Bearer ${BRAIN_MCP_TOKEN}"}}},
+ "_parked":{"_reason":"no identity provides these yet",
+  "cad":{"type":"http","url":"https://x/mcp",
+   "headers":{"Authorization":"Bearer ${CAD_MCP_TOKEN}"}}}}
+JSONEOF
+run "$WORK/parked.json" "$ENVFILE"
+if [ "$rc" -eq 0 ]; then
+  ok "parked server is exempt"
+else
+  bad "parked server is exempt" "rc=$rc $out"
+fi
+
+# --- malformed JSON must not pass silently ------------------------------------
+# A config the checker cannot read is an unverified config, not a clean one.
+printf '{"mcpServers":{' > "$WORK/broken.json"
+run "$WORK/broken.json" "$ENVFILE"
+[ "$rc" -ne 0 ] && ok "unparseable config does not report success" || bad "unparseable config does not report success" "rc=0"
+
+# --- a missing env-file is unverifiable, not clean ----------------------------
+run "$WORK/good.json" "$WORK/no-such-env"
+[ "$rc" -ne 0 ] && ok "missing env-file does not report success" || bad "missing env-file does not report success" "rc=0"
+
+printf '\n%s: %d passed, %d failed\n' "$(basename "$0")" "$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