https://aider.chat/docs/usage/watch.html
I imagine with vim, from the document you're editing, you'd go:
:ter
to get a terminal. Fire up aider with --watch-files in the terminal. Hop back up to the file and start telling it what to do. Hit L when it's done to see the changes.
That's just a guess but after writing it out I kinda want to try it.
When I use aider it's via its chat interface and then I load the file with vim in another terminal tab to follow along but I think --watch-files with vim would be fun.
Just an honest opinion of someone who didn’t have skin in the game. Not sure if it helps.
Totally worth it
I still have PyCharm, especially for working with data which I do a lot it helps quite a bit, but by default I'm back to a very vanilla Vim setup. Others have mentioned tmux which is great and I'd use anyway especially over ssh, but even just terminal tabs for instances of agents are fine frankly.