What I did: Trying to create a Shortcut to append some text to an existing note, configured a shortcut with agenda://x-callback-url/append-to-note?..
What happened: Since iOS assumes Agenda as also the name of the Calendar app in PT-PT language (not sure about PT-BR), it will take the action to the Calendar app instead of Agenda notes. Strangely the App is called Calendário on the home screen.
What I expected: It should take the action to the Agenda notes, instead of the Calendar app.
Things that might be helpful to know (Agenda version, OS and model, etc): Running on iPhone X, iOS 12.0, Agenda 2.2.1