This skill should be used when the user asks to "create a hookify rule", "write a hook rule", "configure hookify", "add a hookify rule", or needs guidance on hookify rule syntax and patterns.
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Method 1 - skills CLI
npx skills i anthropics/claude-code/plugins/hookify/skills/writing-rulesMethod 2 - openskills (supports sync & update)
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Hookify rules are markdown files with YAML frontmatter that define patterns to watch for and messages to show when those patterns match. Rules are stored in .claude/hookify.{rule-name}.local.md files.
---
name: rule-identifier
enabled: true
event: bash|file|stop|prompt|all
pattern: regex-pattern-here
---
Message to show Claude when this rule triggers.
Can include markdown formatting, warnings, suggestions, etc.name (required): Unique identifier for the rule
warn-dangerous-rm, block-console-logenabled (required): Boolean to activate/deactivate
true: Rule is activefalse: Rule is disabled (won't trigger)event (required): Which hook event to trigger on
bash: Bash tool commandsfile: Edit, Write, MultiEdit toolsstop: When agent wants to stopprompt: When user submits a promptall: All eventsaction (optional): What to do when rule matches
warn: Show message but allow operation (default)block: Prevent operation (PreToolUse) or stop session (Stop events)warnpattern (simple format): Regex pattern to match
Example:
event: bash
pattern: rm\s+-rfFor complex rules with multiple conditions:
---
name: warn-env-file-edits
enabled: true
event: file
conditions:
- field: file_path
operator: regex_match
pattern: \.env$
- field: new_text
operator: contains
pattern: API_KEY
---
Condition fields:
field: Which field to check
commandfile_path, new_text, old_text, contentoperator: How to match
regex_match: Regex pattern matchingcontains: Substring checkequals: Exact matchnot_contains: Substring must NOT be presentstarts_with: Prefix checkends_with: Suffix checkpattern: Pattern or string to matchAll conditions must match for rule to trigger.
The markdown content after frontmatter is shown to Claude when the rule triggers.
Good messages:
Example:
⚠️ **Console.log detected!**
You're adding console.log to production code.
**Why this matters:**
- Debug logs shouldn't ship to production
- Console.log can expose sensitive data
- Impacts browser performance
**Alternatives:**
- Use a proper logging library
- Remove before committing
- Use conditional debug buildsMatch Bash command patterns:
---
event: bash
pattern: sudo\s+|rm\s+-rf|chmod\s+777
---
Dangerous command detected!Common patterns:
rm\s+-rf, dd\s+if=, mkfssudo\s+, su\s+chmod\s+777, chown\s+rootMatch Edit/Write/MultiEdit operations:
---
event: file
pattern: console\.log\(|eval\(|innerHTML\s*=
---
Potentially problematic code pattern detected!Match on different fields:
---
event: file
conditions:
- field: file_path
operator: regex_match
pattern: \.tsx?$
- field: new_text
operator: regex_match
pattern: console\.log\(
---
Console.log in TypeScript file!Common patterns:
console\.log\(, debugger, print\(eval\(, innerHTML\s*=, dangerouslySetInnerHTML\.env$, credentials, \.pem$node_modules/, dist/, build/Match when agent wants to stop (completion checks):
---
event: stop
pattern: .*
---
Before stopping, verify:
- [ ] Tests were run
- [ ] Build succeeded
- [ ] Documentation updatedUse for:
Match user prompt content (advanced):
---
event: prompt
conditions:
- field: user_prompt
operator: contains
pattern: deploy to production
---
Production deployment checklist:
- [ ] Tests passing?
- [ ] Reviewed by team?
- [ ] Monitoring ready?Literal characters: Most characters match themselves
rm matches "rm"console.log matches "console.log"Special characters need escaping:
. (any char) → \. (literal dot)( ) → \( \) (literal parens)[ ] → \[ \] (literal brackets)Common metacharacters:
\s - whitespace (space, tab, newline)\d - digit (0-9)\w - word character (a-z, A-Z, 0-9, _). - any character+ - one or more* - zero or more? - zero or one| - ORExamples:
rm\s+-rf Matches: rm -rf, rm -rf
console\.log\( Matches: console.log(
(eval|exec)\( Matches: eval( or exec(
chmod\s+777 Matches: chmod 777, chmod 777
API_KEY\s*= Matches: API_KEY=, API_KEY =
Test regex patterns before using:
python3 -c "import re; print(re.search(r'your_pattern', 'test text'))"Or use online regex testers (regex101.com with Python flavor).
Too broad:
pattern: log # Matches "log", "login", "dialog", "catalog"Better: console\.log\(|logger\.
Too specific:
pattern: rm -rf /tmp # Only matches exact pathBetter: rm\s+-rf
Escaping issues:
"pattern" requires double backslashes \\spattern: \s works as-isLocation: All rules in .claude/ directory
Naming: .claude/hookify.{descriptive-name}.local.md
Gitignore: Add .claude/*.local.md to .gitignore
Good names:
hookify.dangerous-rm.local.mdhookify.console-log.local.mdhookify.require-tests.local.mdhookify.sensitive-files.local.mdBad names:
hookify.rule1.local.md (not descriptive)hookify.md (missing .local)danger.local.md (missing hookify prefix).claude/hookify.{name}.local.md file in project root.local.md fileTemporary: Set enabled: false in frontmatter
Permanent: Delete the .local.md file
See ${CLAUDE_PLUGIN_ROOT}/examples/ for complete examples:
dangerous-rm.local.md - Block dangerous rm commandsconsole-log-warning.local.md - Warn about console.logsensitive-files-warning.local.md - Warn about editing .env filesMinimum viable rule:
---
name: my-rule
enabled: true
event: bash
pattern: dangerous_command
---
Warning message hereRule with conditions:
---
name: my-rule
enabled: true
event: file
conditions:
- field: file_path
operator: regex_match
pattern: \.ts$
- field: new_text
operator: contains
pattern: any
---
Event types:
bash - Bash commandsfile - File editsstop - Completion checksprompt - User inputall - All eventsField options:
commandfile_path, new_text, old_text, contentuser_promptOperators:
regex_match, contains, equals, not_contains, starts_with, ends_with