I use AI to write specific types of unit tests, that would be extremely tedious to write by hand, but are easy to verify for correctness. That aside, it's pretty much useless. Context windows are never big enough to encompass anything that isn't a toy project, and/or the costs build up fast, and/or the project is legacy with many obscure concurrently moving parts which the AI isn't able to correctly understand, and/or overall it takes significantly more time to get the AI to generate something passable and double check it than just doing it myself from the get go.

Rarely, I'm able to get the AI to generate function implementations for somewhat complex but self-contained tasks that I then copy-paste into the code base.

Can you setup automated integration/end-to-end tests and find a way to feed that back into your AI agents before a human looks at it? Either via an MCP server or just a comment on the pull request if the AI has access to PR comments. Not only is your lack of an integration testing pipeline slowing you down, it's also slowing your AI agents down.

"AFAICT, there’s no service that lets me"... Just make that service!

I generally vibe code with vim and my playlist in Cmus.