The hook system — shipped scripts that Claude Code runs on session and tool lifecycle events
Reference
| Event | Exit contract | Typical use |
|---|---|---|
PreToolUse |
0 allow / 2 block |
policy guards (security_guard, worktree_path_guard) |
PostToolUse |
0 |
formatting, telemetry |
SessionStart |
0 |
orientation banners (starter_reconciler) |
SessionEnd / Stop |
0 |
stash notes, lesson reminders |
PreCompact |
0 |
pre-compaction side effects |
Wiring: the plugin's hooks.json maps events → scripts under
attune/hooks/scripts/, each with a timeout.