A familiar production failure looks like this: an AI support agent reads a ticket, decides the customer deserves compensation, calls the refund tool, and refunds the full annual subscription instead of the $12 add-on. The model did not crash. The API did not throw an exception. The tool worked exactly as designed. The postmortem usually starts with the wrong question: “How do we stop the model from making bad decisions?” The better question is: which layer should have stopped the mistake ...