Hook Development

About

Automate and customize Claude's workflow by creating event-driven hooks that respond to lifecycle events like tool use, session start, or task completion. This skill provides comprehensive guidance on building both intelligent, prompt-based hooks for contextual decisions and fast, command-based hooks for deterministic checks. It covers everything from configuration formats and security best practices to advanced patterns, enabling you to enforce policies, validate operations, and integrate external tools seamlessly into your development process.

Key Features

• 229 GitHub stars
• Includes security best practices for input validation and path safety.
• Guidance for all hook events (PreToolUse, PostToolUse, Stop, SessionStart, etc.).
• Covers JSON configuration for both plugin-specific (`hooks.json`) and user settings.
• Explains use of environment variables like `${CLAUDE_PLUGIN_ROOT}` for portable scripts.
• Detailed implementation patterns for both prompt-based and command-based hooks.

Use Cases

• Validate tool calls before execution to block potentially dangerous commands.
• Automatically load project context or set environment variables at the start of a session.
• Enforce task completion standards by verifying tests passed before Claude stops.