hooks-builder

Event-driven hooks intercept Claude Code operations at key moments—PreToolUse, PostToolUse, UserPromptSubmit, SessionStart, and others—letting you run validation scripts, enforce policies, or orchestrate tasks. Create a hook by defining the event, matcher syntax for target operations, and inline or external scripts that return exit code 0 to allow or 2 to block.

Yes. A PreToolUse hook intercepts Write and Edit operations, checks file paths against a matcher pattern, and blocks attempts to modify .env files by returning exit code 2, protecting critical configurations from accidental changes.

Ten hook events cover the full lifecycle: PreToolUse and PostToolUse for tool operations, UserPromptSubmit for input validation, SessionStart and SessionEnd for setup and cleanup, PermissionRequest for access control, Stop and SubagentStop for workflow interruption, Notification for alerts, and PreCompact for context management.

Create PostToolUse hooks that run after code edits or formatting operations, triggering external validation scripts—linters, formatters, or custom checkers—and block commits or saves if standards aren't met by returning exit code 2 with error details.

Yes. Hooks accept inline scripts or command-based execution, JSON input/output contracts for data passing, environment variables for context injection, and robust error handling with debugging guidance for troubleshooting failures.

Hooks enable custom security policies like blocking dangerous tool use, validating user inputs before execution, enforcing coding standards on file writes, logging all operations for audit trails, and orchestrating environment-specific workflows across code editing, testing, and formatting tasks.