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
}
**U…
