Three reasons to return no answer
The source is missing
The first workshop brief says, “Saturday sessions are available.” The selected note contains no schedule. Retrieval returns the statement with no supporting passage.
The sources conflict
A conflict requires two supported statements that cannot both guide the brief. The fixed demonstration contains only one source note, so it records no conflict instead of inventing one.
The answer sits outside the task
Price remains outside the brief because the permitted note supplies none. A fact from another job would not answer the price question for this workshop offer.
A no-answer result still contains useful work
The output names the schedule question, searched source, closest confirmed details, reason the note cannot settle it, and the next source needed. It does not fill the gap with a plausible sentence.
Independent review compares the Saturday statement with the packet and requests removal. The corrected brief keeps the audience, two-hour offer, and confirmed-detail constraint. The checkpoint records schedule and price as unknown.
The job stops when an answer would require invention, a source outside the permitted scope, or a human decision the task did not supply.
When this boundary fits
Use it when claims affect decisions, reputation, money, safety, or later reuse. A creative naming exercise can permit imaginative options, but it should still distinguish invention from sourced fact.
No-answer does not mean no progress. It converts uncertainty into a precise research request and keeps the rest of the artifact usable.