I am also a member of the 30+ year emacs club (with a detour to jetbrains some years back due to java) and it has been crazy how good claude is at implementing/debugging emacs extensions, I have it set up so it has emacs in its container and it is able to basically use it headless to debug whatever.

Saying "I want my editor to do X" and have it happen basically realtime on an editor I fully control is incredible. I have written elisp in the past, but it's definitely one of my weakest languages, so being able to leverage claude to do this is great.