
Retrieval Failure vs Generation Failure: How to Diagnose Which Layer Is Killing Your RAG System
A retrieval-augmented system that answers wrong failed in exactly one of two places — the retriever handed the model garbage, or the model had good material and still wrote garbage. They look identical from the outside and need completely different fixes. This is the diagnostic discipline that stops teams from rewriting prompts for six weeks while retrieval is quietly broken: measure retrieval on its own, then generation on its own, in that order — and fix the layer that's actually failing instead of the one that's cheapest to edit.







