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name: code-review description: Comprehensive guide for reviewing code to ensure it is clean, bug-free, and high-quality. Use when reviewing PRs, checking code quality, or before finalizing changes.

Code Review Skill

This skill provides a rigorous framework for reviewing code. Your goal is to ensure the code is "as clean and bug-free as possible."

When to use this skill

• Before finalizing any implementation task.
• When the user explicitly asks for a code review.
• When you are "verifying" a change and want to double-check your own work.
• When exploring existing code to identify refactoring opportunities.

Review Checklist

Apply these checks to every piece of code you review.

1. Correctness & Logic

• Functional Requirements: Does the code strictly meet the user's requirements?
• Algorithm Correctness: Is the logic sound? Are there no infinite loops or incorrect state updates?
• Typing: Are TypeScript types strict and correct? Avoid any unless absolutely necessary.
• State Management: Is state handled correctly (e.g., React useState, useEffect deps)?

2. Edge Cases & Robustness

• Null/Undefined: Are null and undefined values handled gracefully? (e.g., optional chaining ?., nullish coalescing ??).
• Empty States: How does the UI behaves when lists are empty?
• Error Handling: Are errors caught and handled? Is the user informed of errors?
• Input Validation: Is user input validated before processing?

3. Security

• Secrets: Are hardcoded secrets/keys present? (They should be in .env).
• Injection: Is there protection against XSS/SQL injection? (e.g., using proper libraries/framework features).
• Access Control: Does the code respect user permissions?

4. Performance

• Re-renders: (React) Are there unnecessary re-renders? Are useMemo/useCallback used appropriately?
• Data Fetching: Is data fetching optimized (caching, deduplication)?
• Complexity: Are there O(n^2) or worse operations on potentially large datasets?

5. Style & Maintainability

• Naming: Are variable/function names descriptive and consistent?
• Modularity: Is code broken down into small, reusable functions/components?
• Comments: "Why" is documented, not just "What".
• Dead Code: Is unused code removed?

How to Provide Feedback

When acting as a reviewer:

1. Be Explicit: Quote the line numbers.
2. Categorize: Label issues (e.g., [CRITICAL], [SUGGESTION], [NIT]).
3. Explain Why: "Change X to Y because Z prevents a potential race condition."
4. Suggest Fixes: Provide the corrected code snippet.

Example Usage

If you find a bug:

[CRITICAL] Correctness In utils.ts:45, the loop condition i <= length causes an Index Out of Bounds error because arrays are 0-indexed.

Fix:

Copyfor (let i = 0; i < length; i++) { ... }

If you suggest a cleanup:

[SUGGESTION] Maintainability This logic in Component.tsx is complex. Consider extracting it to a custom hook useCustomLogic.