---
name: codereview-skill
description: Code review best practices and checklist. Use when reviewing PRs, analyzing code quality, or checking for bugs and anti-patterns.
---

# Code Review Skill

## Review Checklist

When reviewing code, check the following:

### Correctness
- Logic is correct and handles edge cases
- No off-by-one errors in loops
- Null/None checks where needed

### Readability
- Variable and function names are descriptive
- Functions do one thing (single responsibility)
- No magic numbers — use named constants

### Security
- No hardcoded secrets or credentials
- User inputs are validated/sanitized
- No SQL injection or command injection risks

## Example: Bad vs Good

```python
# Bad
def f(x):
    return x * 86400  # magic number

# Good
SECONDS_PER_DAY = 86400

def to_seconds(days: int) -> int:
    return days * SECONDS_PER_DAY
```

## Common Anti-patterns to Flag
- Functions longer than 40 lines → suggest splitting
- Deeply nested conditionals (>3 levels) → suggest early return
- Duplicate code blocks → suggest extracting to function