When a chatbot cannot answer reliably, passage retrieval finds relevant text in a document collection and supplies evidence for response generation. In a retrieval-augmented workflow, the system retrieves related passages, generates a candidate answer, checks its support, and may transfer the user to a human agent. section 6.2.2
Checking an uncertain health question
For a question about achalasia, dysphagia, and vaccine side effects, retrieval can return passages defining achalasia, describing vaccine side effects, and connecting dysphagia with esophageal conditions. If the generated answer adds an unsupported claim, the system can avoid presenting it as reliable and connect the user with a specialist. section 6.2.2
