Should I use prompt-based or command hooks?

Use prompt-based hooks for context-aware decisions using natural language, and command hooks for fast, deterministic checks like file system operations or bash scripts.

How do I persist environment variables across a session?

You can use the SessionStart hook and append export commands to the path specified by the $CLAUDE_ENV_FILE environment variable.

Can I run multiple hooks at the same time?

Yes, all matching hooks for a specific event run in parallel for performance. They should be designed to be independent of one another.

What are Claude Code hooks?

Hooks are event-driven scripts or prompts that execute in response to Claude Code events, such as starting a session, using a tool, or finishing a task.

What is the PreToolUse event used for?

PreToolUse allows you to validate, approve, deny, or even modify the inputs of a tool before Claude actually executes the command.

Claude Code Hook Development

Name: Claude Code Hook Development
Author: mbarnes-code

bymbarnes-code

0•

Developer Tools

Implements event-driven automation and validation hooks to enhance Claude Code plugin functionality and security.

This skill provides comprehensive guidance for building advanced hooks in Claude Code, enabling developers to intercept tool calls, validate inputs, and automate complex workflows. It covers the full lifecycle of hook implementation, from deterministic bash-based command hooks for performance to context-aware prompt-based hooks for nuanced reasoning. Use this skill to implement security gates, load persistent project context via SessionStart, and enforce quality standards using PreToolUse and Stop events.

Key Features

01Support for a wide range of events including PreToolUse, PostToolUse, and Stop

020 GitHub stars

03Standardized JSON output formats for permission decisions and system messages

04Implementation of context-aware prompt-based hooks for intelligent validation

05Portable path management using the ${CLAUDE_PLUGIN_ROOT} environment variable

06Execution of deterministic bash command hooks for file system operations

Use Cases

01Automatically injecting project-specific documentation into the session context

02Preventing the execution of destructive commands or sensitive file access

03Verifying task completion and code quality before the agent stops its session

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add mbarnes-code/multi-agent-vllm hook-development

For use in Claude.ai and ChatGPT

Download Skill