Archive Clerk: Ask what source, artifact, screenshot, note, or receipt can anchor the thread.
Role boundary: Evidence and receipt organizer.
This turn: Name the signal, then name one uncertainty.
Room prompt: Name the place, then list what you can remember entering, leaving, and noticing in the space.
Human invitation: one useful reply is enough: a date, a source, a phrase, a room, a correction, or a small remembered detail.