Claude Code Hooks — Automate Your AI Workflow

What it is

Claude Code Hooks are built-in automation triggers in Claude Code that run shell commands in response to specific events: file edits, tool calls, notifications, and agent stops. They let you enforce coding standards, run tests, validate changes, and integrate with external tools automatically.

Hooks target developers using Claude Code who want automated quality checks integrated directly into their AI-assisted workflow without relying on Claude to remember to run them.

How it saves time or tokens

Without hooks, you need to manually remind Claude to run linters, formatters, or tests after each edit. Hooks make this automatic and deterministic. The PostToolUse event fires after every edit or write, so ESLint, Prettier, or your test suite runs without consuming additional tokens on reminder prompts. PreToolUse hooks can block operations before they execute, preventing bad patterns proactively.

How to use

1. Add hooks to your .claude/settings.json:

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Edit|Write",
        "command": "eslint --fix $CLAUDE_FILE_PATH"
      }
    ]
  }
}

1. Every file edit by Claude Code now auto-runs ESLint.

1. Add multiple hooks for different events:

{
  "hooks": {
    "PostToolUse": [
      {
        "matcher": "Edit|Write",
        "command": "prettier --write $CLAUDE_FILE_PATH"
      }
    ],
    "Stop": [
      {
        "matcher": ".*",
        "command": "npm test"
      }
    ]
  }
}

Example

A comprehensive hook configuration for a TypeScript project:

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "command": "echo 'Bash command about to run'"
      }
    ],
    "PostToolUse": [
      {
        "matcher": "Edit|Write",
        "command": "eslint --fix $CLAUDE_FILE_PATH && prettier --write $CLAUDE_FILE_PATH"
      }
    ],
    "Stop": [
      {
        "matcher": ".*",
        "command": "npx tsc --noEmit"
      }
    ]
  }
}

Related on TokRepo

• Coding tools for AI development — tools that enhance AI-assisted coding workflows
• Automation tools — broader automation category

Common pitfalls

• Hook commands that take more than a few seconds block Claude from proceeding; keep hooks fast or run them asynchronously
• The $CLAUDE_FILE_PATH variable is only available for file-related tool events; using it in Stop hooks causes empty path errors
• Hooks run in a shell subprocess; ensure the commands are available in your PATH and not aliased only in your interactive shell