AI generated a race condition in my auth flow — how I found it

Spent 3 days on a bug that only happened in production. Classic. Claude wrote me a Next.js auth middleware that looked perfect. It was refreshing the session in middleware AND in the server component. Race condition on the cookie. **How I debugged it:** 1. Added logs everywhere (Claude helped) 2. Realized two places were writing the same cookie simultaneously 3. Asked Claude "can this code have race conditions?" — it immediately spotted it **Lesson:** Ask Claude to audit its own code for race conditions, especially anything touching auth or state. It'll find what it wrote.