> Parent context: see the root [CLAUDE.md](../CLAUDE.md) for project-wide guidelines and behavioural rules.
> Chained import: `@../CLAUDE.md`

# Guardian Agent Development

Guidelines for the `claude-md-guardian` background-maintenance agent.

## File

`agent/claude-md-guardian.md` — installs to `~/.claude/agents/claude-md-guardian.md`.

## Modifying the Agent

1. Edit `agent/claude-md-guardian.md`.
2. YAML frontmatter fields to preserve:
   - `permissions: [Bash, Read, Write, Edit, Grep, Glob, Skill]`
   - `model: haiku` — token efficiency for routine sync runs.
   - `color: purple` — visual indicator in Claude Code UI.
   - `fork_safe: true` — agent runs independently.
   - `hooks: [SessionStart, PreToolUse, PostToolUse]`.
3. Workflow phases inside the agent:
   - **Assessment** — read `git diff` / `git status` / changed-file counts.
   - **Analysis** — decide if changes are significant enough to update CLAUDE.md.
   - **Update** — invoke the skill for targeted section updates rather than full regeneration (~70–80% token saving vs. rewrite).
4. Re-install for testing: `cp agent/claude-md-guardian.md ~/.claude/agents/`.

## v2.0.0+ Frontmatter Reference

Hooks use Anthropic's canonical keyed-object schema (event → array of `{ matcher, hooks: [{ type, command }] }`):

```yaml
hooks:
  PostToolUse:
    - matcher: "Write|Edit"
      hooks:
        - type: command
          command: "python3 ${CLAUDE_PLUGIN_ROOT}/hooks/validate-claude-md.py"
  InstructionsLoaded:
    - matcher: "session_start|nested_traversal|path_glob_match|include|compact"
      hooks:
        - type: command
          command: "python3 ${CLAUDE_PLUGIN_ROOT}/hooks/validate-claude-md.py"
```

The array-of-`{event, commands}` shape used in earlier versions did not match the documented schema and silently did not fire.

## Skill ↔ Agent Integration

The agent uses `claude-md-enhancer` (the skill's frontmatter name; installed as `claudeforge-skill/`) as its core capability. Invoke it with `Skill: claude-md-enhancer` inside the agent workflow.

Hook responsibilities:

- **SessionStart** — check `git diff`; if significant drift is detected, invoke the skill for an incremental update.
- **PreToolUse** — validate before a CLAUDE.md edit lands.
- **PostToolUse** — after `Edit`/`Write` to any CLAUDE.md, the plugin-level `hooks/hooks.json` runs `hooks/validate-claude-md.py`. The script exits `2` with stderr feedback when the file is over 150 lines; the guardian then proposes a `/sync-claude-md` run.
- **InstructionsLoaded** — same script fires on every `load_reason` (`session_start`, `nested_traversal`, `path_glob_match`, `include`, `compact`), so the cap is enforced deterministically at load time, not just at write time.

## Agent ↔ Git

The agent watches for change signals via:

```bash
git diff --name-status HEAD~10
git log --since="1 week ago" --oneline --no-merges
git diff HEAD~10 -- package.json requirements.txt pyproject.toml go.mod Cargo.toml
```

Triggers an update when any of these hold:

- 5+ files modified since the last sync.
- New dependencies added to a manifest file.
- New top-level directories created (potential new sub-CLAUDE.md candidates).
- Manual invocation after a milestone or release.

When the agent runs sync, it follows `command/sync-claude-md.md`: never commit, leave the diff for the user to review.