Code Reviewer

This skill performs comprehensive code reviews to improve quality, identify issues, and suggest best practices.

When to Use This Skill

Invoke this skill when the user:

• Asks for a code review
• Wants to check code quality
• Needs help identifying bugs or issues
• Requests best practice recommendations
• Mentions code analysis or improvement

Review Process

Step 1: Initial Analysis

Read the code and understand:

1. Purpose and functionality
2. Language and framework used
3. Code structure and organization
4. Dependencies and imports

Step 2: Quality Assessment

Evaluate code across multiple dimensions:

Correctness:

• [ ] Logic errors or bugs
• [ ] Edge cases handled
• [ ] Error handling implemented
• [ ] Return values appropriate

Readability:

• [ ] Clear variable/function names
• [ ] Consistent formatting
• [ ] Appropriate comments
• [ ] Logical code organization

Performance:

• [ ] Efficient algorithms
• [ ] No redundant operations
• [ ] Appropriate data structures
• [ ] Resource management

Security:

• [ ] Input validation
• [ ] No hardcoded credentials
• [ ] SQL injection prevention
• [ ] XSS protection (if applicable)

Maintainability:

• [ ] DRY principle followed
• [ ] Single responsibility
• [ ] Low coupling, high cohesion
• [ ] Easy to extend

Step 3: Generate Feedback

Provide structured feedback:

Critical Issues (must fix):

• Bugs that cause failures
• Security vulnerabilities
• Data loss risks

Warnings (should fix):

• Performance problems
• Maintainability issues
• Best practice violations

Suggestions (nice to have):

• Code style improvements
• Optimization opportunities
• Alternative approaches

Step 4: Code Examples

For each issue, provide:

1. Location (file:line)
2. Description of problem
3. Why it matters
4. Suggested fix with code example

Review Template

Use this structure for reviews:

## Code Review Summary

**Overall Quality:** [Excellent/Good/Fair/Needs Improvement]
**Lines Reviewed:** [Number]
**Critical Issues:** [Number]
**Warnings:** [Number]
**Suggestions:** [Number]

## Critical Issues

### 1. [Issue Title]
**Location:** file.py:42
**Problem:** [Description]
**Impact:** [Why this matters]
**Fix:**
```language
[Code example of suggested fix]

Warnings

[Same structure as Critical Issues]

Suggestions

[Same structure as Critical Issues]

Positive Observations

• [Good pattern 1]
• [Good pattern 2]

Overall Recommendations

[High-level guidance for improvement]

## Common Review Patterns

**Pattern 1: Bug Identification**
- Trace execution flow
- Check boundary conditions
- Verify error handling
- Test edge cases mentally

**Pattern 2: Security Review**
- Audit all user inputs
- Check authentication/authorization
- Review data handling
- Examine external calls

**Pattern 3: Performance Analysis**
- Identify bottlenecks
- Check algorithmic complexity
- Review database queries
- Examine loop efficiency

**Pattern 4: Maintainability Check**
- Assess code clarity
- Check for duplication
- Evaluate modularity
- Review documentation

## Language-Specific Checks

**Python:**
- PEP 8 compliance
- Pythonic idioms
- Type hints usage
- Exception handling

**JavaScript/TypeScript:**
- ESLint compatibility
- Async/await usage
- Type safety (TS)
- Modern syntax

**Go:**
- Error handling patterns
- Goroutine safety
- Interface usage
- Idiomatic Go

**Other Languages:**
- Follow language conventions
- Use standard library features
- Apply community best practices

## Example Review

**Input Code:**
```python
def get_user(id):
    user = db.query("SELECT * FROM users WHERE id = " + id)
    return user

Review Output:

Critical Issues

1. SQL Injection Vulnerability Location: example.py:2 Problem: String concatenation in SQL query allows injection attacks Impact: Attacker could execute arbitrary SQL, accessing or deleting data Fix:

def get_user(id):
    user = db.query("SELECT * FROM users WHERE id = ?", (id,))
    return user

Warnings

2. Missing Error Handling Location: example.py:1-3 Problem: No handling for invalid ID or database errors Impact: Function crashes on errors instead of graceful handling Fix:

def get_user(user_id):
    try:
        user = db.query("SELECT * FROM users WHERE id = ?", (user_id,))
        return user if user else None
    except DatabaseError as e:
        logger.error(f"Database error retrieving user {user_id}: {e}")
        return None

Suggestions

3. Parameter Naming Location: example.py:1 Problem: Parameter named id shadows Python built-in Impact: Minor - can cause confusion, not a functional issue Fix:

def get_user(user_id):
    # ... rest of function

Validation Checklist

Before completing review:

• [ ] All code sections examined
• [ ] Security vulnerabilities identified
• [ ] Performance issues noted
• [ ] Best practices applied
• [ ] Examples provided for fixes
• [ ] Positive patterns acknowledged
• [ ] Overall recommendations given

Review Scope Options

Quick Review:

• Focus on critical issues only
• Security and correctness
• 5-10 minutes

Standard Review:

• All quality dimensions
• Critical + warnings
• 15-30 minutes

Comprehensive Review:

• All dimensions + suggestions
• Alternative approaches
• Refactoring ideas
• 30+ minutes

Ask the user which scope they prefer if unclear.