A RAG That Says “Not in This Document” Has to Show Four Kinds of Evidence

A Retrieval-Augmented Generation (RAG) system must provide evidence when it cannot find an answer in a document, rather than simply stating "not found." This defensible negative response requires four kinds of evidence, each from a different component of the system's architecture. The parsing component must provide a coverage report detailing what was successfully extracted, such as the number of pages, tables, and images processed. The question-parsing stage must show the exhaustive set of keywords and concepts used for the search, while the retrieval stage must confirm that a full sweep of the document was performed, not just a limited top-k search. Finally, the generation component synthesizes this evidence to deliver a trustworthy and verifiable "no answer" verdict.