Making abstention the product and converging all three layers on a single INSUFFICIENT_EVIDENCE token is the part I like most, since a docs assistant that guesses is worse than one that says it does not know. Using a stronger judge model than the generator for faithfulness and context precision is the detail most people get backwards, and enforcing retrieval recall as a CI ratchet so a regression fails the build is exactly how you keep a RAG system honest over time. The post-hoc citation validation that refuses to cache ungrounded answers is a clean way to stop a bad answer from becoming a permanent one.