How to write a skill.md file

# [Skill Name]

## Purpose
[What this skill does in 1-2 sentences. When Claude Code
should use it.]

## Procedure
1. [First step — be specific about what to do]
2. [Second step — include tools/commands to run]
3. [Third step — what to check before moving on]
4. [Continue for as many steps as needed]
5. [Final step — how to verify the result]

## Rules
- [Constraint 1: e.g., "Never delete existing code without asking"]
- [Constraint 2: e.g., "Always run tests after changes"]
- [Constraint 3: e.g., "Document any assumptions made"]

## Output Format
[Describe what the result should look like:
- A markdown file with specific sections
- A code file with specific structure
- A report with before/after metrics
- etc.]

# Code Review Skill

## Purpose
Perform a thorough code review on a PR or diff,
catching bugs, style issues, and architectural concerns.

## Procedure
1. Read the full diff. Understand what changed and why.
2. Check for obvious bugs:
   - Off-by-one errors
   - Missing null/undefined checks
   - Race conditions in async code
   - Unhandled promise rejections
3. Check for style issues:
   - Naming consistency
   - Function length (>30 lines is a smell)
   - Code duplication that should be extracted
4. Check for architectural concerns:
   - Does this change fit the existing patterns?
   - Are there new dependencies that could be avoided?
   - Is the change in the right layer of the codebase?
5. Run the existing tests to verify nothing breaks.

## Rules
- Focus on correctness first, style second
- Flag security issues immediately
- Don't nitpick formatting (that's a linter's job)
- If something is confusing, ask about it rather than
  assuming it's wrong

## Output Format
Markdown with sections:
- Summary (1-2 sentences)
- Critical issues (must fix before merge)
- Suggestions (nice to have)
- Questions (things that need clarification)