I'm trying to create a tool in python where a user splits a road (a polyline feature of shapefile) and the tool automatically recalculates the road ranges depending on where it was split. I know how to have a tool access information from features selected before the tool is run, but I'm wondering, is it possible for a python script or arcMap model to prompt the user to select a feature? This functionality could make my solution to this problem much simpler.

EDIT: I didn't know that python addins existed! My foray into addins is proving to be the correct path for this venture.