How to verify whether an AI answer is grounded in source documents

A grounded response should identify the source document, the relevant location, and the excerpt that supports the claim. The excerpt should answer the question—not merely contain a related keyword.

question -> retrieve candidates -> inspect evidence
         -> answer only from supported text
         -> abstain when support is absent

Test the system with questions that are answerable, ambiguous, and unsupported. The unsupported case matters most: a reliable system says that the information was not found instead of filling the gap with a plausible sentence.