create-hooks

Claude Code hooks are created by configuring JSON structures for specific events like PreToolUse, PostToolUse, or SessionStart to automate validation, logging, and context injection. You must define event-specific inputs, outputs, matcher patterns, and timeouts to ensure stable workflow control.

Use command hooks for fast, deterministic shell-based tasks like blocking unsafe git commands, and choose prompt hooks when you need semantic checks and reasoning. Deciding between command and prompt hooks depends on whether your validation task requires simple pattern matching or complex logic evaluation.

Yes, PreToolUse hooks can block destructive commands by applying matcher patterns to targeted tools and returning the correct JSON output schema to deny execution. This allows you to enforce safety checks and prevent unsafe operations before a tool runs.

Prevent stop-hook loops by applying stop-hook loop safeguards within your hook configuration and setting appropriate timeouts. Managing hook reliability requires JSON validation and permission checks to keep your SessionStart, SessionEnd, and Stop event workflows stable.

Yes, PostToolUse hooks support automatic code formatting by triggering actions immediately after a tool finishes editing. Configuring event-driven hooks for PostToolUse allows you to react to file modifications and apply formatting without altering core behavior.

Matchers are limited by their dependency on correct JSON hook configuration and event-specific input schemas. If matcher patterns are misconfigured or timeout settings are too restrictive, hook workflows may fail to trigger properly or cause unintended interruptions during tool execution.