I use vim as well, and one editor-agnostic coding assistant that is pretty decent is Aider. It is a little buggy sometimes, but it's been a blast to experiment with. I run it in a separate split with Tmux. Its whole schtick is to use it as a pair programming device. So I'll edit code in one split and use Aider in another, alternating at key points. This has worked pretty well for personal projects. I typically don't do this at $dayjob, though.