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pbakaus_impeccable/skill/reference/hooks.md
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Paul BakausandClaude Fable 5 c3aba1e343 hooks: two-tier design hook — immediate per-edit rules + full-set Stop deep pass
Eval evidence showed the per-edit PostToolUse stream fires overwhelmingly
on copy-level rules (em-dash-overuse ~97x/session) and measurably makes
models more conservative, while a full-detector pass at completion is what
actually fixes contrast/padding/glow. Split the hook accordingly:

- Per-edit (PostToolUse) now surfaces only IMMEDIATE_TIER_RULES: broken
  output (broken-image, text-overflow, clipped-overflow-container,
  body-text-viewport-edge), objective contrast/legibility failures
  (low-contrast, gray-on-color, tiny-text), single-property mechanical
  slop (gradient-text, dark-glow), and design-system drift (the four
  design-system-* rules, which compound if left uncorrected). Everything
  else defers. Override with hook.perEditRules: "all" in
  .impeccable/config.json. Tiering is off for Cursor/Copilot harnesses,
  which have no Stop pass wired, so nothing gets silently dropped there.

- Stop deep pass (runStopHook): runs the FULL rule set over every UI file
  touched this session (tracked via the existing hook.cache.json session
  state; deferred-only edits now mark the file touched), dedupes against
  everything already surfaced per-edit, honors ignore-rule/file/value and
  inline disables, reuses the [impeccable@1] envelope, and no-ops fast
  when no UI files were touched. Emits hookSpecificOutput
  { hookEventName: "Stop", additionalContext } per the Claude Code SDK
  Stop contract (conversation continues so the model can act on it).
  Second Stop fire is silent - deep-pass findings are remembered.

- Wiring: Stop entries (timeout 30) in plugin/hooks/hooks.json, the
  .claude settings + .codex hooks manifests (transformers + hook-admin
  repair path). Claude Code and Codex both dispatch a native Stop event;
  Cursor's stop hook is inconsistently dispatched (pre-write gate stays)
  and Copilot's agentStop/sessionEnd don't inject model context, so
  neither gets a Stop entry - documented in reference/hooks.md.

- Tests: tiering split/override/harness gating, Stop dedupe + silent
  no-touched-files + ignore machinery + kill switches; existing per-edit
  tests moved to immediate-tier rule ids. 181 tests green; smoke-tested
  the built dist skill end to end (glow surfaced per-edit, em-dash only
  at Stop, second Stop silent).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
2026-07-11 16:46:00 -07:00

10 KiB

/impeccable hooks

Manage the design detector hook for the current project.

The hook runs the impeccable design detector on direct file edits to design-relevant files (.tsx, .jsx, .html, .vue, .svelte, .astro, .css, .scss, .sass, .less, .ts, .js). Claude Code, Codex, and GitHub Copilot use a post-tool-use hook and push a short system reminder into the agent's context after the edit; findings get a correction prompt, pending issues get a re-nudge, and clean UI-ish files get a short ack unless quiet mode is on (hook.quiet in config). Plain .ts and .js files are still scanned, but stay quiet unless the detector finds something. Cursor uses preToolUse to block bad proposed writes before they land and stays silent when it allows a clean write.

The detector rules run in two tiers. The per-edit hook surfaces only the immediate tier: mechanical, unambiguous problems worth interrupting an edit for, such as broken images, overflowing or clipped content, contrast and legibility failures, gradient text, glow shadows, and design-system drift. Everything else (copy cadence, palette and typography taste, layout rhythm) is deferred to a deep pass on the Stop hook event, which runs the full rule set over every UI file touched in the session and surfaces the remaining findings once, deduplicated against what the per-edit pass already reported. A session that touched no UI files stops silently. Set hook.perEditRules to "all" in .impeccable/config.json to restore the full rule set on every edit. The Stop deep pass is wired for Claude Code and Codex, which both dispatch a native Stop hook event. Cursor does not get one (its stop hook is not consistently dispatched; the pre-write gate covers it), and GitHub Copilot's stop-style events do not feed context back to the model, so Copilot keeps the full rule set per edit instead of deferring.

This command toggles the hook per project by editing .impeccable/config.json (the unified Impeccable config; hook runtime settings live under its hook key, and shared detector ignores live under detector). Per-developer overrides, including the install consent decision (hook.consent) the CLI records, live in the gitignored .impeccable/config.local.json. Set hook.enabled: false to turn the hook off, hook.quiet: true to silence the clean/pending acks, or hook.auditLog to a file path for an NDJSON log. The legacy IMPECCABLE_HOOK_DISABLED, IMPECCABLE_HOOK_QUIET, and IMPECCABLE_HOOK_LOG env vars are still honored and override these config values when set.

Declare server-side template extensions under detector.extensions when the project uses Blade, Twig, ERB, or Handlebars files; the hook skips them otherwise because they sit outside the built-in extension list. One entry per extension, { "ext": ".blade.php", "engine": "html" }. engine picks the analyzer (html for markup templates, text for JS/TS/CSS-like files) and defaults to html. Match against the end of the filename, so double extensions like .blade.php and .html.erb work. Config only adds extensions; the built-in list always applies.

Manual npx impeccable detect scans use the same project filter config by default: detector.ignoreRules, detector.ignoreFiles, detector.ignoreValues, and detector.designSystem.enabled. hook.enabled only controls automatic hook execution, not manual CLI scans. Use npx impeccable detect --no-config ... for a raw detector run that ignores project config/context. Use npx impeccable ignores ... for direct CLI CRUD on the same detector ignores.

Supported harnesses: Claude Code (.claude/settings.local.json in the project, which is gitignored so the hook stays machine-local; a hook you move into the shared settings.json is honored in place too), Codex (.codex/hooks.json in the project), Cursor (.cursor/hooks.json in the project), and GitHub Copilot (.github/hooks/impeccable.json in the project, a team-shared committed file that both the Copilot CLI and the cloud agent read). For the Copilot CLI, repo-level hooks fire once .github/hooks/impeccable.json is committed to the repository's default branch.

On Cursor, preToolUse checks proposed Write/Edit/Shell write content and denies only when the real detector finds an issue. The denial message is visible to the agent as the tool error, so the agent can reconsider before the bad write lands.

Routing

The first argument is the action. Defaults to status.

Action What it does
status Print current state, shared/local config paths, ignored rules / files / values, env override.
on Set enabled: true in .impeccable/config.json, record local hook consent as accepted, and install/repair provider hook manifests when the skill is installed.
off Set enabled: false in .impeccable/config.json.
ignore-rule <id> Append <id> to detector.ignoreRules; for overused-font, requires --all-values.
ignore-file <glob> Append <glob> to detector.ignoreFiles.
ignore-value <id> <value> [--shared] [--reason "..."] Append a rule/value suppression to shared .impeccable/config.json.
ignore-value <id> <value> --local [--reason "..."] Append a private rule/value suppression to .impeccable/config.local.json.
reset Delete the project config, dedup cache, and Cursor pending queue.

Flow

  1. Resolve the action from the user's argument. If no action was given, default to status.

  2. Invoke the admin script and pass the user's output through verbatim:

    node {{scripts_path}}/hook-admin.mjs <action> [args...]
    
  3. If <action> is off, follow up with a one-line note: "Done. New edits will not trigger the design hook in this project until you run {{command_prefix}}impeccable hooks on."

  4. If <action> is on, follow up with: "Done. The design hook will fire after the next Edit/Write/MultiEdit on a UI file."

  5. If <action> is ignore-value, ignore-file, or ignore-rule, just print the script output. The default scope is shared .impeccable/config.json; add --local only when the user explicitly asks for a private exception.

  6. If <action> is status, just print the script output. Do not add commentary unless the user asked a follow-up question.

Intentional findings

The hook itself never writes ignore config. Persist an exception only after the user explicitly confirms the flagged issue is intentional, and always go through hook-admin.mjs.

Prefer the narrowest exception:

  • If the finding line shows an exact ignore-value command, run that command. This writes shared .impeccable/config.json by default.
  • For value-specific findings such as overused-font and bounce-easing, use ignore-value when the user confirms the specific value. Do not use ignore-rule overused-font for a specific font.
  • If the finding has no value-specific command, such as side-tab, prefer ignore-file <path> for the current file.
  • Use ignore-rule <id> only when the user asks to suppress that whole rule across the project. For broad overused-font suppression, use ignore-rule overused-font --all-values only when the user asks to ignore overused fonts generally.
  • Prefer config ignores (the commands above) by default; they keep suppressions in one reviewable place. Reach for an inline comment only when the waiver must travel with a single file that leaves the repo (a generated/exported standalone document, an emailed HTML file). The supported marker is impeccable-disable <rule> (whole file) or impeccable-disable-line / impeccable-disable-next-line (one line), in any comment syntax, with an optional reason after : or --. The detector honors it by default; --no-inline-ignores or --no-config bypasses it.

Example value-specific exception:

node {{scripts_path}}/hook-admin.mjs ignore-value overused-font Inter --shared --reason "User confirmed Inter is intentional"

Example intentional motion exception:

node {{scripts_path}}/hook-admin.mjs ignore-value bounce-easing bounce-ball --shared --reason "User confirmed ball bounce animation is intentional"

Example whole-rule font exception:

node {{scripts_path}}/hook-admin.mjs ignore-rule overused-font --all-values --reason "User asked to ignore overused fonts generally"

Example file-scoped exception:

node {{scripts_path}}/hook-admin.mjs ignore-file "src/legacy/Card.tsx"

Constraints

  • Never modify .impeccable/config.json or .impeccable/config.local.json by hand from this command. Always go through hook-admin.mjs so writes stay validated and the file shape stays consistent. One exception: detector.extensions has no admin action, so when the user asks to cover a template stack, edit that one field in .impeccable/config.json directly and leave the rest of the file untouched.
  • Do not edit the hook scripts themselves (hook.mjs, hook-lib.mjs, hook-before-edit.mjs) from this flow. Those are skill plumbing.
  • Cursor can block a proposed write when the detector finds a real issue. Claude Code, Codex, and GitHub Copilot do not block the edit; they emit a post-edit reminder instead. Disabling stops both blocking and reminders.
  • The hook is bundled with the Impeccable skill and installed through project-local manifests: .claude/settings.local.json, .codex/hooks.json, .cursor/hooks.json, and .github/hooks/impeccable.json. On Codex, the user must approve the hook via /hooks the first time. On Cursor, confirm hooks are enabled under Settings -> Hooks. On GitHub Copilot, the CLI loads .github/hooks/impeccable.json once it is committed to the repository's default branch, and the cloud agent reads it from the repo directly.

Failure modes

  • If .impeccable/config.json or .impeccable/config.local.json is unreadable or malformed, the hook ignores that file and uses the remaining valid config/defaults. hook-admin.mjs status will show malformed files as ignored.
  • If the user asks to "disable the hook" globally, lead with {{command_prefix}}impeccable hooks off (persistent for this project; writes hook.enabled: false to config). The legacy IMPECCABLE_HOOK_DISABLED=1 env var also works as a one-shot override that follows the shell.