Starting note 8.5 Sidebar plug-in from note mask

Is there a possibility in the Notes 8.5 client to listen to LotusScript-, JavaScript- or Lotus Formula “events” without large implementation complexity (without implementation of an corresponding Notes Agent)?Maybe there is a corresponding Listener API (e.g. lotuslabs) or sth. like that?

Goal: I have a button in a Notes Mask (or Hotspot etc.) which should be able to start a Notes/Eclipse (sidebar) plug-in.

Do you have any suggestions?

TIA