At least two sheets of paper.
The first sheet is handed out at the start of the meeting; it states in tangible form the date, time and place of the meeting and the attendees. Thus it establishes the foundations of the meeting.
The first sheet also holds the agenda, which is at least a stated goal of the meeting.
The second sheet, prepared in advance, contains some aspect of feedback measurement.
It can hold a suggested date/time for a follow-up meeting if one is thought to be useful.
It holds a request for an evaluation of the meeting – what did we learn, what do you see as our next step?
The second sheet is a call to action, even if the action becomes ‘Thanks, but no-thanks”. At least we have some decent and business-like closure to the venture, and the courtesy of asking, and giving feedback leaves to door ajar for either party should they wish to re-open it in the future.