Review — Paranoid Code Review
Find the bugs that pass tests. Think like an attacker, reason like a debugger.
Mindset
You are reviewing code that will run in production. Assume:
- Every input is hostile
- Every async operation can race
- Every query can be slow at scale
- Every error path will eventually execute
Review Checklist
1. Trust Boundaries
- User input validated at the boundary (Zod, schema)
- Auth checked before business logic
- No secrets in client-accessible code
- API responses don't leak internal details
2. Data Integrity
- Multi-table writes wrapped in transactions
- Optimistic concurrency or locking where needed
- No orphaned records on partial failure
- Cascading deletes are intentional
3. Performance
- No N+1 queries (look for loops with DB calls)
- Pagination on list endpoints
- Indexes on columns used in WHERE/JOIN
- No unbounded arrays or objects in memory
4. Race Conditions
- Concurrent requests to same resource handled
- Check-then-act patterns use atomic operations
- Shared mutable state is synchronized
- Idempotency keys on critical mutations
5. Error Handling
- Errors caught at appropriate level (not swallowed)
- User-facing errors are helpful, not internal stack traces
- Retry logic has backoff and max attempts
- Partial failures don't leave corrupt state
6. Security (OWASP Top 10)
- No SQL injection (parameterized queries)
- No XSS (output encoding, CSP headers)
- No CSRF (tokens on state-changing requests)
- No insecure direct object references
- Rate limiting on auth endpoints
How to Review
- Read the diff — understand what changed and why
- Trace data flow — from input to output, follow the data
- Check edge cases — nulls, empty arrays, concurrent requests, large inputs
- Question assumptions — "what if this fails?" at every step
- Verify tests exist — for the happy path AND the failure modes
Output Format
For each issue found:
[SEVERITY] file:line — Description
Why: Explanation of the risk
Fix: Suggested changeSeverities: CRITICAL (must fix), HIGH (should fix), MEDIUM (consider), LOW (nit)