What are prompt-based hooks in Claude Code?

Prompt-based hooks use natural language instructions to let the LLM evaluate whether a specific action, such as a tool call, should be approved, denied, or modified based on the current context.

What is the difference between PreToolUse and PostToolUse?

PreToolUse executes before a tool runs to allow for validation or modification of inputs, while PostToolUse executes after completion to analyze results and provide feedback.

How do matchers work in hook configuration?

Matchers use exact strings, regex, or wildcards to define which tools or events a hook should apply to, such as matching all 'Write' operations or all MCP-prefixed tools.

How do I persist environment variables across a Claude session?

You can use a SessionStart hook to append export commands to the $CLAUDE_ENV_FILE, which ensures those variables are available to Claude for the duration of the session.

Can I use bash scripts to validate Claude's actions?

Yes, command hooks allow you to execute deterministic bash scripts for tasks like file system checks, running linters, or integrating with external CLI tools.

Hook Development for Claude Code

Name: Hook Development for Claude Code
Author: chrismcgraw60

bychrismcgraw60

Herramientas para Desarrolladores

Streamlines the creation of event-driven hooks to automate, validate, and secure Claude Code plugin workflows.

Acerca de

This skill provides a comprehensive framework for building Claude Code hooks, allowing developers to intercept and respond to lifecycle events such as tool execution, session starts, and agent completion. It supports both prompt-based hooks for nuanced, LLM-driven decision making and command hooks for deterministic bash-based validations. By implementing these patterns, developers can enforce security policies, automate environment setup, and ensure high-quality output through automated checks and context-aware reasoning within the Claude Code CLI environment.

Características Principales

Support for full lifecycle events including PreToolUse and SessionStart
Context-aware prompt-based hooks for intelligent validation
Environment variable persistence via specialized session hooks
Deterministic command hooks for bash script integration
0 GitHub stars
Security-first patterns for path traversal and input validation

Casos de Uso

Automating project initialization and context loading at the start of every session
Enforcing security policies by blocking unauthorized file writes or dangerous commands
Implementing custom quality gates to verify code changes before the agent completes a task

Acerca de

Características Principales

Support for full lifecycle events including PreToolUse and SessionStart
Context-aware prompt-based hooks for intelligent validation
Environment variable persistence via specialized session hooks
Deterministic command hooks for bash script integration
0 GitHub stars
Security-first patterns for path traversal and input validation

Casos de Uso

Automating project initialization and context loading at the start of every session
Enforcing security policies by blocking unauthorized file writes or dangerous commands
Implementing custom quality gates to verify code changes before the agent completes a task