Edit /.claude/settings.json or per-project .claude/settings.json: json { "hooks": { "PostToolUse": [ { "matcher": "Edit", "hooks": [ {"type": "command", "command": "pnpm tsc --noEmit"} ] } ] } }

Auto-format on Save json {"matcher": "Write|Edit", "hooks": [ {"type": "command", "command": "pnpm prettier --write $CLAUDEFILEPATH"} ]} TypeScript Check Before Commit json {"matcher": "Bash", "hooks": [ {"type": "command", "command": "echo $CLAUDETOOLARGS | grep -q 'git commit' && pnpm tsc --noEmit"} ]} Block Sensitive File Edits PreToolUse hook that exits with code 1 if Claude tries to edit .env files — stops the action. Slack Notification on Session End json {"matcher": "", "hooks": [ {"type": "command", "command": "curl -X POST $SLACKWEBHOOK -d '{\"text\": \"Claude session ended\"}'"} ]}

Environment Variables Available

$CLAUDEFILEPATH: the file being edited - $CLAUDETOOLNAME: the tool being used - $CLAUDETOOLARGS: the arguments - $CLAUDESESSIONID: the session ID

0: allow - 1: block (Claude sees an error and adjusts) - 2: silent block (no feedback to model)

Hooks can run any shell command — be careful with PostToolUse Bash hooks. A malicious project could ship a .claude/settings.json that exfiltrates secrets. Mitigate: review hook config in untrusted projects before opening.

Hooks block the tool — keep them fast. Anything over 200ms degrades Claude Code's responsiveness.

Read [how to use Claude Code](https://vibecodingturkey.com/en/rehberler/how-to-use-claude-code) for the basics.

Claude Code Hooks Guide 2026 — Guide

Q: Available Hooks

PreToolUse: before a tool runs (block or modify) - PostToolUse: after a tool runs (validate, format) - UserPromptSubmit: when the user hits Enter on a prompt - SessionStart: new session begins - SessionEnd: session ends - Notification: any notification fires

Claude Code Hooks Guide 2026

Claude Code hooks are shell commands the CLI runs at specific lifecycle events. They turn the editor into a programmable system. Available Hooks - PreToolUse: before a tool runs block or modify - PostToolUse: after a tool runs validate, format - UserPromptSubmit: when the user hits Enter on a prompt - SessionStart: new session begins - SessionEnd: session ends - Notification: any notification fir…

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