Writing Hookify Rules

This teaches Claude Code how to write hookify rules, which are markdown files with YAML frontmatter that let you define patterns to watch for during development and trigger custom messages when they match. The rules live in `.claude/hookify.{rule-name}.local.md` files and can fire on different events like bash commands, file changes, or prompts. It's useful if you want Claude to remind you about team conventions, warn about dangerous operations, or enforce project-specific patterns without hardcoding checks everywhere. The skill covers the basic structure with regex patterns and event types, though the source doesn't show many real-world examples of rules in action.