Bubble Trouble: Why Top‑K Retrieval Keeps Letting LLMs Down
The problem is not finding documents. It is spending the prompt budget badly. Ask an enterprise RAG system for “scope of work,” and the system may look confident for exactly the wrong reason. The query sounds simple. Somewhere in the document set, there is probably a sheet, paragraph, or clause literally called “Scope of Works.” A flat top-k retriever will happily grab the highest-scoring chunks from that section, stack them into the model context, and call the job done. Very tidy. Very wrong. ...