I understand that you are planning an agenda where it is possible to add participants and mail the agenda to them.
It would be very nice, if it is possible to have private notes that the participants don’t receive but is relevant for the leader when conducting the meeting.
We haven’t decided the final form of this yet, but likely it would allow you to share a note between participants. They would see that note in their own copy of Agenda, and could even edit it.
The leader can always make other notes that are not shared, and thus private to him/her.