fix(hooks): narrow inject matchers — Mac CPU fix D

[namastex888]

Summary

Fix D of the 5-step .19 Mac-CPU root-cause plan. Eliminates wasted bun cold-starts caused by hook-event matchers that fire dispatchers for events with zero handlers.

Root cause

src/hooks/inject.ts:buildHooksConfig() wired the team settings.json with { matcher: '*' } for every event in DISPATCHED_EVENTS:

• PreToolUse ✓ — has 9 handlers, broad coverage justified
• PostToolUse ✗ — only 1 handler (runtime-emit-msg with matcher /^SendMessage$/); wiring * meant Bash/Read/Write/Edit post-uses each spawned a useless bun fork
• SessionStart ✗ — 0 handlers
• SessionEnd ✗ — 0 handlers
• TeammateIdle ✗ — 0 handlers
• TaskCompleted ✗ — 0 handlers

On a busy Mac dev machine this multiplied the cold-start fanout that fixes A and C already addressed.

Fix

• types.ts — replace flat DISPATCHED_EVENTS array with DISPATCHED_EVENT_MATCHERS map. Only PreToolUse: '*' and PostToolUse: 'SendMessage' are wired. DISPATCHED_EVENTS retained as a derived array for backward-compat (other consumers unchanged).
• inject.ts — buildHooksConfig() uses per-event matchers. injectIntoFile() refactored into single-responsibility helpers (readSettings, allEventsAlreadyInjected, hasNoObsoleteGenieEntries, pruneObsoleteGenieEntries, refreshMatcherEntries, upsertGenieEntry).
• Pruning: cleans up SessionStart/SessionEnd/TeammateIdle/TaskCompleted from pre-fix-D installed settings.json. User-defined hooks under those events are PRESERVED — only genie's own dispatch entries are pruned.
• Refresh: existing genie entries get their matcher rewritten on next inject (so PostToolUse * → SendMessage).

Validation

• bun test src/hooks/__tests__/inject.test.ts — 10/10 pass (6 prior + 4 new):
  • DISPATCHED_EVENT_MATCHERS only wires events that have handlers
  • PostToolUse is wired with SendMessage matcher (not '*')
  • injectIntoFile prunes obsolete genie entries on re-inject
  • injectIntoFile preserves user-defined hooks under obsolete events
• bun x tsc --noEmit clean
• bun x biome check clean (no complexity warnings, all formatting auto)

Where this fits in the .19 Mac-CPU sprint

• A ✓ fix(db): drop runRetention from getConnection — Mac CPU fix A (hook-dispatch coldstart) #1475 — drop runRetention from getConnection
• filewatch ✓ fix(filewatch): replace fs.watch recursive with chokidar (Mac CPU partial mitigation) #1474 — chokidar replacement
• C ✓ fix(hooks): skip db boot for dispatch — Mac CPU fix C #1476 — GENIE_SKIP_DB_BOOT for hook dispatch
• D — this PR
• B queued — needsSeed mtime-marker cache (lower priority post-C since hooks now skip seed entirely)
• E queued — persist session-sync cache file

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[gemini-code-assist]

Code Review

This pull request optimizes the hook injection process to mitigate performance issues on Mac-CPU environments by reducing unnecessary dispatcher invocations. It replaces the generic event list with a mapping that uses specific tool matchers and excludes events without handlers. The injection logic is refactored to support pruning obsolete entries and refreshing existing ones. Feedback indicates that the logic for skipping redundant injections is currently too lenient and should be strengthened to verify timeouts and prevent stale entries.

[gemini-code-assist]

The short-circuit logic in allEventsAlreadyInjected is too lenient. It returns true if it finds at least one matching genie entry, but it does not verify that the timeout matches DISPATCH_TIMEOUT, nor does it ensure the absence of stale genie entries (e.g., an old * matcher remaining alongside a new SendMessage matcher). This could lead to the injection process skipping necessary updates or leaving redundant dispatcher invocations in settings.json if the configuration is in a partially updated state.

function allEventsAlreadyInjected(existingHooks: HooksConfig, hooksConfig: HooksConfig): boolean {
  return DISPATCHED_EVENTS.every((event) => {
    const existing = existingHooks[event] ?? [];
    const desired = hooksConfig[event][0];
    const desiredCommand = desired.hooks[0].command;
    const desiredMatcher = desired.matcher;

    const genieEntries = existing.filter((m) => m.hooks?.some((h) => isGenieDispatchCommand(h.command)));
    if (genieEntries.length === 0) return false;

    // Ensure all genie entries for this event match the desired configuration
    return genieEntries.every((m) =>
      m.matcher === desiredMatcher &&
      m.hooks.every((h) =>
        !isGenieDispatchCommand(h.command) ||
        (h.command === desiredCommand && h.timeout === DISPATCH_TIMEOUT)
      )
    );
  });
}

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Restrict pruning to deprecated hook events only

pruneObsoleteGenieEntries currently treats every event outside DISPATCHED_EVENTS as obsolete, so a re-inject removes genie hook dispatch entries from still-supported events like UserPromptSubmit/Stop (handlers are registered in src/hooks/index.ts). In practice, teams that manually enabled dispatch for those events will silently lose those hooks the next time injectTeamHooks runs, which is a functional regression introduced by this cleanup path.

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[chatgpt-codex-connector]

Avoid rewriting shared matcher blocks in-place

When a matcher block contains both the genie dispatch hook and user-defined hooks, refreshMatcherEntries rewrites the entire block’s matcher to genieEntry.matcher. For PostToolUse, this changes * to SendMessage and unintentionally narrows user hooks in the same block, so their commands stop running for other tools after reinjection. The matcher update should be isolated to genie’s own entry instead of mutating shared entries.

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