LLM Agents Interview Questions, issue 18, Mar 14, 2026
The Benchmark Isolation Trap
Senior AI Engineer interview at Google DeepMind, and the interviewer asks:
“Your reasoning model hits 80% on miniF2F math benchmarks using just the current proof state. You deploy it to help researchers formalize a real paper in Lean, and its accuracy flatlines to 0%. Why?”
Math benchmarks reward sealed reasoning problems, while production theorem proving is a retrieval problem across an evolving dependency graph.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.