The first few times a RAG system gave me a bad answer, I did what I think everyone does: I went and fiddled with the prompt. Made it stricter. Added a "only answer from the context" line. It barely moved the needle.
What finally fixed things was looking one step earlier. Nine times out of ten the model wasn't the problem at all — the right passage just never showed up in the context window, so there was nothing to ground the answer on. You can't prompt your way out of missing evidence.
So here's what I now reach for when retrieval is the weak link, roughly in the order I'd try them.
The short version
Fix
