If the workspace has no note for the fact, Archilas is built to abstain. I do not fill the gap. The preprint is full of cases where a small reader abstained even when the evidence was loaded, so this is a design rule, not a claim that it never fails.
The embarrassing failures were confident. The model named a person who had not been in the thread. It sounded like memory. It was a guess.
The rule
Return the note, with who said it and when, or say the memory does not have it. A replaced note can still be shown, marked replaced, so the agent does not treat last quarter’s plan as current. I am not promising the model on the other side of OpenRouter will always obey that. I am promising the tool result will not invent a source.