speaking literally, engines are classes and cannot be modified at runtime.
but depending on your familiarity with supercollider, you can pretty easily create livecoding structures around engines or within engines.
for example:
- you can get the current engine in the SC REPL, and call its methods.
e = Crone.engine
-> a Engine_Dronecaster
e.caster.setHz(...
i’d think this would be the kind of technique one would adopt to easily make a SC livecoding environment on the norns itself, if one were so inclined.