Claude Code//.claude//hooks

- Event-driven scripts that Claude Code runs automatically at lifecycle points — written in JavaScript (or shell), live in `.claude/hooks/`.

Event-driven scripts that Claude Code runs automatically at lifecycle points — written in JavaScript (or shell), live in .claude/hooks/.

Referenced from settings

Each script receives JSON on stdin with the tool name and input.

Exit codes control behavior — 0 = allow, 2 = block (stdout becomes the reason shown to Claude)

PreToolUse:: fires before a tool executes. Can block it. Use matcher to filter by tool name.

PostToolUse:: fires after a tool succeeds. Good for linting or type-checking after edits.

Stop:: fires when Claude finishes responding. Good for summary validation.

UserPromptSubmit:: fires when the user sends a message. Can intercept or transform.

SessionStart / SessionEnd:: session lifecycle.