| name | code-review |
| description | Review code changes for bugs, security vulnerabilities, performance issues, and maintainability. Use when asked to review code, a PR, a diff, or recent changes. |
Code Review
Step 1: Understand the change
Run git diff to see what changed. If reviewing a specific commit: git show <hash>.
Read the modified files in full, not just the diff. Context matters.
Step 2: Trace the impact
For every modified function or type:
- Find its callers with
grep
- Check if the change breaks any existing contract (signature, return type, side effects)
- Check if related tests still cover the new behavior
Step 3: Check for issues
Go through each changed file and look for:
Correctness
- Logic errors, wrong conditions, off-by-one
- Missing null/undefined checks at system boundaries
- Unhandled error cases or silently swallowed exceptions
- Incorrect async handling (missing await, unhandled promise rejections)
- Race conditions in concurrent code
Security
- Injection: SQL, shell command, path traversal, XSS
- Hardcoded secrets, tokens, or credentials
- Missing input validation on user-controlled data
- Missing authorization checks
- Insecure deserialization or parsing
Performance
- N+1 queries or loops that could be batched
- Unnecessary re-renders, recomputations, or allocations
- Blocking I/O in async code
- Missing indexes for new query patterns
Maintainability
- Unclear naming or misleading comments
- Functions doing too many things
- Dead code or unused imports left behind
- Duplicated logic that should be shared
Step 4: Report
Format your review as follows. Be direct. Do not pad with praise. Only mention things that matter.
Summary
One sentence describing what the change does.
Critical (must fix before merge)
file.ts:42 — Exact problem. Why it is a bug or security issue.
Warnings (should fix)
file.ts:100 — Problem and suggested fix.
Suggestions (optional)
file.ts:150 — Improvement with rationale. Clearly marked as optional.
Verdict
One of: APPROVE / REQUEST CHANGES / NEEDS DISCUSSION with a one-sentence reason.
