How to catch AI hallucinations before they reach production

LLMs hallucinate. That's not news. What's underdiscussed is how that failure mode behaves in long working sessions: confident reconstruction that looks fluent, cites specifics, and feels right — until three sessions later when something supposed to be true turns out not to be. This is week 5 of an 8-week deep dive on CRAFT for Cowork , a structured working environment for Claude. The QA framework treats AI reliability as a measurable engineering problem. The four gates CRAFT's verification core