Code Reviewer Skill

A comprehensive code review skill that analyzes code quality, security, performance, and best practices.

When to Use

Invoke this skill when:

• User asks to review code or a pull request
• User requests code quality analysis
• User wants security or performance audit
• Commands: /review, /code-review, /pr-review

Capabilities

1. Code Quality Analysis

• Dead code detection
• Unused imports/variables
• Code duplication (DRY violations)
• Complexity metrics (cyclomatic complexity)
• Function/method length analysis
• Naming conventions

2. Security Review

• SQL injection vulnerabilities
• XSS vulnerabilities
• Command injection risks
• Hardcoded secrets/credentials
• Insecure dependencies
• Authentication/authorization issues
• Input validation gaps

3. Performance Analysis

• N+1 query detection
• Inefficient algorithms
• Memory leaks
• Unnecessary re-renders (React)
• Bundle size concerns
• Caching opportunities

4. Best Practices

• SOLID principles adherence
• Design pattern usage
• Error handling
• Logging practices
• Test coverage gaps
• Documentation completeness

Review Process

Step 1: Understand Context

1. Identify the language/framework
2. Understand the purpose of the code
3. Check for existing patterns in the codebase
4. Review any related tests

Step 2: Systematic Review

Use the checklist at checklist.md to perform a thorough review.

Step 3: Categorize Findings

Severity	Description	Action Required
Critical	Security vulnerabilities, data loss risks	Must fix before merge
High	Bugs, significant performance issues	Should fix before merge
Medium	Code quality issues, minor bugs	Consider fixing
Low	Style issues, minor improvements	Optional
Info	Suggestions, alternative approaches	For consideration

Step 4: Provide Actionable Feedback

For each issue found:

**[SEVERITY] Issue Title**
- File: `path/to/file.ts:line`
- Problem: Clear description of the issue
- Impact: What could go wrong
- Fix: Specific code suggestion or approach

Output Format

# Code Review Summary

## Overview
- Files reviewed: X
- Issues found: Y (X Critical, Y High, Z Medium)
- Recommendation: [Approve / Request Changes / Needs Discussion]

## Critical Issues
[List critical issues with fixes]

## High Priority
[List high priority issues]

## Medium Priority
[List medium priority issues]

## Low Priority & Suggestions
[List minor issues and improvements]

## Positive Observations
[Highlight good practices found]

## Summary
[Brief summary and next steps]

Language-Specific Checks

TypeScript/JavaScript

• Type safety (any usage, type assertions)
• Null/undefined handling
• Async/await patterns
• React hooks rules
• Memory management in closures

Python

• Type hints usage
• Exception handling
• Resource management (context managers)
• Import organization
• PEP 8 compliance

Go

• Error handling patterns
• Goroutine leaks
• Race conditions
• Interface design
• Context propagation

Rust

• Ownership/borrowing patterns
• Error handling (Result/Option)
• Unsafe block justification
• Memory safety

Integration

With Git

# Review staged changes
git diff --cached | claude review

# Review specific commit
git show <commit> | claude review

# Review PR (with gh cli)
gh pr diff <number> | claude review

Automated Checks

The skill can integrate with:

• ESLint/Prettier configurations
• SonarQube rules
• Custom linting rules
• CI/CD pipelines

Configuration

Create .claude/review-config.json to customize:

{
  "severity_threshold": "medium",
  "ignore_patterns": ["*.test.ts", "*.spec.ts"],
  "focus_areas": ["security", "performance"],
  "custom_rules": [],
  "max_file_size": 1000
}

Examples

Example 1: Quick Review

User: Review this function for issues

function getData() {
  var data = fetch('/api/data')
  return data
}

Response: Found 3 issues:

1. [Medium] Missing async/await - fetch returns Promise
2. [Low] Use const instead of var
3. [Low] Add error handling