Claude Code hook

Agents reach for Grep and Glob out of habit. With the hook installed, every such search in Claude Code also gets a short note from repomap: where the symbol is defined, who calls it (with file:line), and which module it belongs to. Glob searches get the matching files and how central they are. The search itself still runs; the hook only adds context.

npx -y @sylphx/repomap setup --claude-hooks     # install (idempotent)
npx -y @sylphx/repomap setup --remove           # remove repomap, hook included

This adds one entry to ~/.claude/settings.json:

{
  "hooks": {
    "PreToolUse": [
      { "matcher": "Grep|Glob", "hooks": [{ "type": "command", "command": "repomap hook", "timeout": 10 }] }
    ]
  }
}

When repomap is not on your PATH, the command is npx -y @sylphx/repomap hook. For a faster hook, run npm i -g @sylphx/repomap and then setup --claude-hooks again.

What Claude sees

For Grep with the pattern function compose\( in hono:

repomap (code map) for this search:
- function `compose` defined at src/compose.ts:15 (module router); 3 callers: Hono.route (src/hono-base.ts:228), Hono.#dispatch (src/hono-base.ts:452), every (src/middleware/combine/index.ts:102)
Next: repomap `context <symbol>` for code + callers, `impact <symbol>` before editing.

Behaviour

• It reads the index from the per-file cache, so it answers in tens of milliseconds on most repos. If the index is not ready within 4 s (REPOMAP_HOOK_TIMEOUT_MS), it stays silent.
• It never blocks or changes the tool call, and on any error it prints nothing.
• It only works inside a git repository, and never in your home directory.
• Output is capped at about 1,800 characters.