Code Review Skill | Agent Skills

Code Review

Perform structured, actionable code reviews.

When to Use

Reviewing a pull request or set of changes
Evaluating code quality before merging
Auditing a module for technical debt
Establishing review standards or checklists

Review Dimensions

Review code across these dimensions, in priority order:

1. Correctness

Does the code do what it claims?
Are edge cases handled? (null, empty, overflow, concurrency)
Are error paths tested?
Do tests cover the changed behavior?

2. Security

Input validation at system boundaries
No secrets in code (API keys, passwords, tokens)
SQL/command injection prevention
Proper authentication and authorization checks
See security-audit skill for deeper analysis

3. Readability

Clear naming (variables, functions, classes)
Functions do one thing
No deep nesting (max 3 levels)
Comments explain "why", not "what"
Consistent style with the surrounding codebase

4. Maintainability

No unnecessary abstractions
DRY without over-abstraction (rule of three)
Dependencies are justified
Breaking changes are flagged

5. Performance

Only flag when there is a real concern (hot path, large data, N+1 queries)
Do not micro-optimize unless the context demands it

Review Output Format

Structure feedback as:

## Review: <PR title or file>

### Must Fix
- [ ] **file.py:42** — [Correctness] Description of the issue and suggested fix

### Should Fix
- [ ] **file.py:78** — [Readability] Description and suggestion

### Consider
- [ ] **file.py:100** — [Performance] Optional improvement

### Positive
- file.py:15 — Good use of context manager for resource cleanup

Severity levels:

| Level | Meaning | Merge? | |-------|---------|--------| | Must Fix | Bug, security issue, or broken contract | Block | | Should Fix | Significant readability/maintainability concern | Request changes | | Consider | Optional improvement, style preference | Approve with comment | | Positive | Good patterns worth highlighting | - |

Guidelines

Be specific - Point to exact lines, suggest concrete alternatives
Explain why - "This could cause X because Y", not just "change this"
Separate style from substance - Automate style (linters); review logic manually
Limit scope - Review what changed, not the entire file (unless asked)
Acknowledge good work - Include at least one positive observation
Propose, don't impose - "Consider using X" not "You must use X" (unless it's a Must Fix)

Agent Skills: Code Review

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