RAG debugging: hallucinations often trace back to retrieval failures, not the model itself
No-Age-3362 · reddit · 2026-09-29
The author keeps hitting the same failure mode when debugging RAG systems: teams blame the model for hallucinating, but the real culprit is retrieval — the needed chunk never came back, so the model answered from priors. The two failures look identical from outside yet require opposite fixes.
He notes logging retrieved chunks alongside answers only catches part of it (someone still has to read logs), and measuring retrieval recall independently usually requires labelled data most teams don't have. The post asks how practitioners separate retrieval quality from answer quality, or whether they just tune the pipeline as one number until output looks right.
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