Writing Hookify Rules

Create a markdown file named .claude/hookify.{rule-name}.local.md with YAML frontmatter containing name, enabled, event, and pattern fields, followed by the warning message body. Rules are read dynamically, so they take effect on the next tool use.

Hookify rules support bash, file, stop, prompt, and all event types. Bash matches commands, file matches Edit/Write/MultiEdit operations, stop fires on completion, and prompt matches user input.

Yes, set the optional action field to block in the frontmatter. This prevents the operation on PreToolUse events or stops the session on Stop events; omitting it defaults to warn.

Use the advanced conditions format with a list of field, operator, and pattern entries instead of a single pattern. All conditions must match for the rule to trigger, with operators like regex_match, contains, equals, and starts_with.

Common causes are unescaped special characters like dots and parentheses, or patterns that are too broad or too specific. Test patterns with python3 -c "import re; print(re.search(...))" and prefer unquoted YAML patterns to avoid double-backslash issues.

Set enabled to false in the rule's frontmatter to deactivate it without deleting the file. To remove it permanently, delete the .local.md file from the .claude directory.