Add automatic design hook install and exceptions (#170)

* docs: add PRD for design detector hook integration

Plans a PostToolUse hook for Claude Code and Codex that runs the
existing design detector after every relevant file write and feeds
findings back to the agent as advisory system-reminder context. No
implementation in this commit; covers UX, technical design, build
pipeline changes, distribution, coverage tradeoffs, and rollout.

Co-authored-by: Cursor <cursoragent@cursor.com>

* docs: revise hook PRD with best-practices review

Folds in the P0/P1/P2 findings from an online best-practices critique
against the official Claude Code and Codex hook references plus 10+
2026 community guides and similar prior-art tools (claw-hooks,
claude-code-hooks-mastery).

Key changes:
- Exec form everywhere (Codex snippet was shell form), with Windows
  rationale.
- Default timeout dropped from 10s to 5s.
- Re-entrancy guard (CLAUDE_HOOK_DEPTH) and per-file edit counter.
- Session-scoped finding dedup promoted from open question to v1.
- Per-language inline-ignore syntax map (HTML/JSX/CSS/JS).
- Hard-skip rules for sensitive paths and generated/lock files.
- Honest framing about Claude Code lacking per-plugin hook disable.
- Honest framing about Bash-written files being invisible in v1.
- Codex Windows-not-supported call-out, feature flag note, trust ceremony detail.
- Optional NDJSON audit log via IMPECCABLE_HOOK_LOG.
- Findings cap lowered 8 → 5 with attention-budget rationale.
- Versioned envelope ([impeccable@1]) on rendered template.
- Expanded test plan, decision log, and stdin payload appendix.

Co-authored-by: Cursor <cursoragent@cursor.com>

* feat(hooks): ship the design detector hook for Claude Code and Codex

Implements docs/hooks-prd.md: a PostToolUse hook that runs the
impeccable design detector after every Edit/Write/MultiEdit on a UI
file and pushes findings into the agent's next-turn context as a
short system reminder. Silent on clean files. Never blocks an edit.

Why this matters: today, design slop (side-tab borders, gradient
text, purple/cyan palettes, bounce easing, etc.) only gets caught
when a human notices or someone explicitly runs /impeccable audit.
The hook closes the loop at the moment slop is written.

What ships in v1
- skill/scripts/hook.mjs: PostToolUse entry. Reads stdin, runs the
  detector in-process (no `npx impeccable` cold start), emits
  hookSpecificOutput.additionalContext when fresh findings exist.
- skill/scripts/hook-lib.mjs: extracted helpers (config, cache,
  filter, render, audit log, runHook orchestrator). 100% unit-testable.
- skill/scripts/hook-session-start.mjs: SessionStart greeting,
  gated by a project-scannable probe + 30-day throttle.
- skill/scripts/hook-admin.mjs: backs /impeccable hooks
  on/off/status/ignore-rule/ignore-file/reset.

Hardening built in
- Re-entrancy guard (IMPECCABLE_HOOK_DEPTH) so the hook can never
  recursively spawn itself.
- Hard-skip regexes for sensitive paths (.env, .pem, id_rsa,
  secrets, credentials, .git) and generated/lock/build output. These
  fire before the file is even read; cannot be turned off via config.
- Path-traversal check on the inbound file_path.
- Session-scoped dedup keyed by (session, file, rule, line) so the
  same finding never lands in context twice. Prevents the ~12.5K
  wasted tokens per chatty session called out in the PRD.
- Per-(session, file) edit counter with a one-shot suppression
  notice on the 7th edit, silent after.
- Fail-open contract: every error path returns exit 0 with no
  stdout. Optional NDJSON audit log via IMPECCABLE_HOOK_LOG.

Three kill switches (precedence high to low):
1. IMPECCABLE_HOOK_DISABLED env var (1/true/yes/on, case-insensitive)
2. .impeccable/hook.json `enabled: false`
3. /impeccable hooks off slash command (writes the JSON)

Inline ignores are language-aware. `// impeccable: ignore <rule>` for
JS/TS, `<!-- impeccable: ignore <rule> -->` for HTML/Vue/Svelte/Astro,
`{/* impeccable: ignore <rule> */}` for JSX/TSX, `/* impeccable:
ignore <rule> */` for CSS. `*` matches any rule. Directive applies
to the next non-blank line. Same shape as ESLint, Stylelint, Biome.

Build pipeline
- scripts/lib/transformers/hooks.js: per-provider hooks.json
  builders, plus the slim .codex-plugin/plugin.json manifest.
- providers.js: emitHooks: 'claude' for claude-code, emitHooks:
  'codex' for codex and agents. Codex also emits emitCodexPlugin.
- factory.js: emits hooks/hooks.json next to the skills tree.
- build.js: syncs hooks/ into harness roots and into the slim
  plugin/ subtree; writes .codex-plugin/plugin.json. Build is
  idempotent (verified: 98 staged files unchanged across two runs).

Claude Code wiring uses exec form (command + args) and the
${CLAUDE_PLUGIN_ROOT} placeholder. Matcher: Edit|Write|MultiEdit.
`if:` glob filters to UI extensions before spawning Node. PostToolUse
timeout 5s, SessionStart timeout 3s.

Codex wiring uses ${PLUGIN_ROOT} (Codex's native placeholder),
matcher Edit|Write|apply_patch, no `if:` analog (the script does the
extension filter). macOS and Linux only; hooks are disabled on
Windows in current Codex builds. The trust ceremony and feature flag
are documented in README.md.

Routing
- /impeccable hooks lives outside the 23-command router table on
  purpose: it is plumbing, not a design skill. The hidden
  routing slot is added to SKILL.md alongside pin/unpin so the LLM
  knows to dispatch it. The 23-command count and all stale-count
  validators remain happy.

Tests
- tests/hook.test.mjs: 38 unit tests covering env parsing, config
  load + defaults + malformed, cache round-trip + GC,
  ignoreRules/minSeverity/inline ignores (all four languages),
  globbing with **/*/{a,b}, render template with cap + clamp + 0-line
  prefix drop, audit log NDJSON, payload event-name parameterization,
  re-entrancy, kill switches, sensitive-path + generated-path +
  traversal skips, allowlist filter, config ignoreFiles, edit
  counter cycle including the 7th-edit notice, MultiEdit and
  apply_patch payload shapes, detector throw swallow, malformed
  stdin, missing file race.
- tests/hook-build.test.mjs: 18 integration tests covering hook
  manifest shape (matcher, timeouts, exec form, if: glob, placeholders),
  Codex differences (${PLUGIN_ROOT}, no if:, no SessionStart),
  Codex plugin manifest (no inline hooks field to avoid the
  duplicate-file error), routing across the hooksJsonFor table, and
  presence of all three committed artifacts plus the bundled detector
  the runtime relative-import path depends on.

Full suite: 175 bun tests + 186 node tests, all green.

Docs
- README.md: new "Design hook" section explaining default behavior,
  per-project / global / inline disable paths, the JSON schema knobs,
  the audit log debug flag, and the slop / a11y coverage split.
- HARNESSES.md: flips the `hooks` row for Codex from No -> Yes
  (Claude was already Yes), adds a per-harness hook-surface table
  with the manifest location and matcher each provider uses.

Open questions from the PRD intentionally deferred to v2: Bash-write
blind spot, effort-aware suppression, Stop-hook session summary,
per-rule severity, async hook mode. None block v1.

Co-authored-by: Cursor <cursoragent@cursor.com>

* Fix Codex hook scanning: apply_patch paths and co-located stylesheets

Parse file targets from Codex apply_patch command bodies, co-scan imported
and sibling CSS when UI components are edited, drop the git-sweep PostToolUse
group, and align Codex SessionStart manifest and trust docs with the official
hooks spec.

Co-authored-by: Cursor <cursoragent@cursor.com>

* Gitignore hook session cache and drop local test HTML

Hook dedup/throttle state in .impeccable/hook.cache.json is per-project
runtime data like other .impeccable/ sidecars. Remove an untracked
bad-nested-flexbox scratch page from site/public/.

Co-authored-by: Cursor <cursoragent@cursor.com>

* Fix Claude Code hook: drop Edit-only if filter so Write/MultiEdit fire

Claude's if permission rule binds to one tool name, so Edit(*.{…}) never
spawned the hook on Write or MultiEdit despite the matcher listing them.
Extension filtering now lives in hook-lib on both Claude and Codex.

Co-authored-by: Cursor <cursoragent@cursor.com>

* Surface Cursor design findings via stop-hook followup

Replace dropped postToolUse additional_context with afterFileEdit recording
and a one-shot stop followup_message so anti-pattern nudges reach the agent.

Co-authored-by: Cursor <cursoragent@cursor.com>

* Fix design hook packaging and scans

* Fix Cursor hook pending bucket fallback

* Fix Sass hook scan coverage

* Fix Cursor hook review findings

* Fix session start dead hook normalization

* Fix hook config and relative scan paths

* Remove SessionStart design hook

* Remove redundant afterFileEdit normalization

* Fix Cursor suppression and module style scans

* Fix sensitive path hook filter

* Fix disabled Cursor stop hook emission

* Refresh hook harness artifacts

* Fix Cursor hook manifest install

* Add hook ignore-value support

* Ignore hook runtime files locally

* Fix Codex plugin hook packaging

* fix: address PR review bot findings

Block numeric hook depth counters from re-entering.

Avoid following stylesheet imports from traversal-looking hook targets.

* fix: gate ignore-value suggestions by supported rules

Only render exact ignore-value commands when the same finding can be suppressed by ignoreValues.

* Package Codex plugin as hook-only

* Remove Codex plugin packaging

* Recover hook install probe plumbing

* Remove Codex hook packaging follow-up doc

* Remove extra hook docs and skill wording changes

* Install real design hooks via skills CLI

* Add provider hook smoke runner

* Fix Cursor hook delivery with preToolUse gate

* Simplify Cursor hook install to preToolUse

* Clarify confirmed hook exceptions

* Persist hook ignores in shared config

* Guard font hook exceptions

* Fix hook install after main rebase

* Fix hook scan target handling

* fix: address hook review findings

* Address hook review feedback

* Stabilize DeepSeek insert live fixture

* Fix Cursor hook Python shell write bypass

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

cli/engine/node/file-system.mjs

@@ -11,7 +11,7 @@ const SKIP_DIRS = new Set([
 ]);
 
 const SCANNABLE_EXTENSIONS = new Set([
-  '.html', '.htm', '.css', '.scss', '.less',
+  '.html', '.htm', '.css', '.scss', '.sass', '.less',
   '.jsx', '.tsx', '.js', '.ts',
   '.vue', '.svelte', '.astro',
 ]);