Code Review Skill

You now have expertise in conducting comprehensive code reviews. Follow this structured approach:

Review Checklist

1. Security (Critical)

Check for:

• Injection vulnerabilities: SQL, command, XSS, template injection
• Authentication issues: Hardcoded credentials, weak auth
• Authorization flaws: Missing access controls, IDOR
• Data exposure: Sensitive data in logs, error messages
• Cryptography: Weak algorithms, improper key management
• Dependencies: Known vulnerabilities (check with npm audit, pip-audit)

2. Correctness

Check for:

• Logic errors: Off-by-one, null handling, edge cases
• Race conditions: Concurrent access without synchronization
• Resource leaks: Unclosed files, connections, memory
• Error handling: Swallowed exceptions, missing error paths
• Type safety: Implicit conversions, any types

3. Performance

Check for:

• N+1 queries: Database calls in loops
• Memory issues: Large allocations, retained references
• Blocking operations: Sync I/O in async code
• Inefficient algorithms: O(n^2) when O(n) possible
• Missing caching: Repeated expensive computations

4. Maintainability

Check for:

• Naming: Clear, consistent, descriptive
• Complexity: Functions > 50 lines, deep nesting > 3 levels
• Duplication: Copy-pasted code blocks
• Dead code: Unused imports, unreachable branches
• Comments: Outdated, redundant, or missing where needed

5. Testing

Check for:

• Coverage: Critical paths tested
• Edge cases: Null, empty, boundary values
• Mocking: External dependencies isolated
• Assertions: Meaningful, specific checks

Review Output Format

## Code Review: [file/component name]

### Summary
[1-2 sentence overview]

### Critical Issues
1. **[Issue]** (line X): [Description]
   - Impact: [What could go wrong]
   - Fix: [Suggested solution]

### Improvements
1. **[Suggestion]** (line X): [Description]

### Positive Notes
- [What was done well]

### Verdict
[ ] Ready to merge
[ ] Needs minor changes
[ ] Needs major revision

Common Patterns to Flag

• SQL / command injection
• Mutable shared state
• Resource leak
• Missing null / boundary handling
• Callback hell or deeply nested logic

Review Workflow

1. Understand context: Read description and linked issues
2. Run the code: Build and test locally if possible
3. Read top-down: Start with main entry points
4. Check tests: Are changes tested?
5. Security scan: Run automated tools
6. Manual review: Use checklist above
7. Write feedback: Be specific and kind