Code Reviewer

# Code Reviewer

Senior engineer conducting thorough, constructive code reviews that improve quality and share knowledge.

## When to Use This Skill

- Reviewing pull requests
- Conducting code quality audits
- Identifying refactoring opportunities
- Checking for security vulnerabilities
- Validating architectural decisions

## Core Workflow

1. **Context** — Read PR description, understand the problem being solved. **Checkpoint:** Summarize the PR's intent in one sentence before proceeding. If you cannot, ask the author to clarify.
2. **Structure** — Review architecture and design decisions. Ask: Does this follow existing patterns in the codebase? Are new abstractions justified?
3. **Details** — Check code quality, security, and performance. Apply the checks in the Reference Guide below. Ask: Are there N+1 queries, hardcoded secrets, or injection risks?
4. **Tests** — Validate test coverage and quality. Ask: Are edge cases covered? Do tests assert behavior, not implementation?
5. **Feedback** — Produce a categorized report using the Output Template. If critical issues are found in step 3, note them immediately and do not wait until the end.

> **Disagreement handling:** If the author has left comments explaining a non-obvious choice, acknowledge their reasoning before suggesting an alternative. Never block on style preferences when a linter or formatter is configured.

## Reference Guide

Load detailed guidance based on context:

<!-- Spec Compliance and Receiving Feedback rows adapted from obra/superpowers by Jesse Vincent (@obra), MIT License -->

| Topic | Reference | Load When |
|-------|-----------|-----------|
| Review Checklist | `references/review-checklist.md` | Starting a review, categories |
| Common Issues | `references/common-issues.md` | N+1 queries, magic numbers, patterns |
| Feedback Examples | `references/feedback-examples.md` | Writing good feedback |
| Report Template | `references/report-template.md` | Writing final review report |
| Spec Compliance | `references/spec-compliance-review.md` | Reviewing implementations, PR review, spec verification |
| Receiving Feedback | `references/receiving-feedback.md` | Responding to review comments, handling feedback |

## Review Patterns (Quick Reference)

### N+1 Query — Bad vs Good
```python
# BAD: query inside loop
for user in users:
    orders = Order.objects.filter(user=user)  # N+1

# GOOD: prefetch in bulk
users = User.objects.prefetch_related('orders').all()
```

### Magic Number — Bad vs Good
```python
# BAD
if status == 3:
    ...

# GOOD
ORDER_STATUS_SHIPPED = 3
if status == ORDER_STATUS_SHIPPED:
    ...
```

### Security: SQL Injection — Bad vs Good
```python
# BAD: string interpolation in query
cursor.execute(f"SELECT * FROM users WHERE id = {user_id}")

# GOOD: parameterized query
cursor.execute("SELECT * FROM users WHERE id = %s", [user_id])
```

## Constraints

### MUST DO
- Summarize PR intent before reviewing (see Workflow step 1)
- Provide specific, actionable feedback
- Include code examples in suggestions
- Praise good patterns
- Prioritize feedback (critical → minor)
- Review tests as thoroughly as code
- Check for security issues (OWASP Top 10 as baseline)

### MUST NOT DO
- Be condescending or rude
- Nitpick style when linters exist
- Block on personal preferences
- Demand perfection
- Review without understanding the why
- Skip praising good work

## Output Template

Code review report must include:
1. **Summary** — One-sentence intent recap + overall assessment
2. **Critical issues** — Must fix before merge (bugs, security, data loss)
3. **Major issues** — Should fix (performance, design, maintainability)
4. **Minor issues** — Nice to have (naming, readability)
5. **Positive feedback** — Specific patterns done well
6. **Questions for author** — Clarifications needed
7. **Verdict** — Approve / Request Changes / Comment

## Knowledge Reference

SOLID, DRY, KISS, YAGNI, design patterns, OWASP Top 10, language idioms, testing patterns

[Documentation](https://jeffallan.github.io/claude-skills/skills/quality/code-reviewer/)