What I did:
Click “Connect to Calendar” link from a note.
Privacy tab of Security & Privacy System Preferences opened, but didn’t show entry for Agenda.
What I expected:
Privacy tab of Security & Privacy System Preferences would open, and show an entry for Agenda which I would then be able to check the box.
Things that might be helpful to know (Agenda version, OS and model, etc):
Agenda version: MAS 1.1
MacBookPro (Retina, 15-inch, Mid 2014)