code-review

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.