Hook Development

Hook Development for Claude Code Plugins

Overview

Hooks are event-driven automation scripts that execute in response to Claude Code events. Use hooks to validate operations, enforce policies, add context, and integrate external tools into workflows.

Key capabilities:

• Validate tool calls before execution (PreToolUse)
• React to tool results (PostToolUse)
• Enforce completion standards (Stop, SubagentStop)
• Load project context (SessionStart)
• Automate workflows across the development lifecycle

Hook Types

Prompt-Based Hooks (Recommended)

Use LLM-driven decision making for context-aware validation:

{
  "type": "prompt",
  "prompt": "Evaluate if this tool use is appropriate: $TOOL_INPUT",
  "timeout": 30
}

Supported events: Stop, SubagentStop, UserPromptSubmit, PreToolUse

Benefits:

• Context-aware decisions based on natural language reasoning
• Flexible evaluation logic without bash scripting
• Better edge case handling
• Easier to maintain and extend

Command Hooks

Execute bash commands for deterministic checks:

{
  "type": "command",
  "command": "bash ${CLAUDE_PLUGIN_ROOT}/scripts/validate.sh",
  "timeout": 60
}