In every user test I have run on an AI-assisted tool, the first question was the same: where did that come from?

Design for the follow-up

An answer without a source forces the user to re-do the work to trust it, which means the feature saved nothing. A quoted passage with a link to the paragraph it came from lets them verify in two seconds, and two seconds of verification is what converts a demo into a tool people use for real decisions.

• Cite at the sentence level where you can, not the document level. "It is in this 40-page policy" is not a citation.
• Show when the source was last updated. Stale but confident is the failure mode users fear most.
• Make "I could not find this" a first-class response with the same visual weight as an answer.