Hook Development

Claude Code hooks validate tool usage by configuring a hooks.json file with event-driven triggers like PreToolUse and PostToolUse. You define prompt-based hooks for flexible reasoning or command hooks for deterministic checks to enforce safe tool actions.

Prompt-based hooks enable complex, flexible reasoning for validating actions, while command-based hooks perform deterministic checks. Both are defined in a hooks.json file with proper timeouts and portable paths using ${CLAUDE_PLUGIN_ROOT} to ensure safe automated workflows.

You can prevent dangerous commands by implementing a PreToolUse hook in your hooks.json. This event-driven validation hook intercepts tool inputs before execution, applying policies to block unsafe actions automatically.

Load project context automatically by configuring a SessionStart hook in your hooks.json. This event-driven hook triggers at session initialization to inject contextual data, ensuring your workflow has the necessary runtime information loaded.

Hook Development supports portable plugin configurations by using the ${CLAUDE_PLUGIN_ROOT} variable in your hooks.json. This allows you to define portable paths for scripts and commands, ensuring hooks resolve correctly across different environments.

Available events for event-driven workflows include PreToolUse, PostToolUse, Stop, SessionStart, and notifications. These events allow you to load context, validate actions, and coordinate workflows across tools within your Claude Code plugins.