I've tried nearly all the models, they all work best if and only if you will never handle the code ever again. They suck if you have a solution and want them to implement that solution.

I've tried explaining the implementation word and word and it still prefers to create a whole new implementation reimplementing some parts instead of just doing what I tell it to. The only time it works is if I actually give it the code but at that point there's no reason to use it.

There's nothing wrong with this approach if it actually had guarantees, but current models are an extremely bad fit for it.

Yes, I only plan/implement on fully AI projects where it's easy for me to tell whether or not they're doing the thing I want regardless of whether or not they've rewritten the codebase.

For actual work that I bill for, I go in with intructions to do minimal changes, and then I carefully review/edit everything.

That being said, the "toy" fully-AI projects I work with have evolved to the point where I regularly accomplish things I never (never ever) would have without the models.

There are domains of programming (web front end) where lots of requests can be done pretty well even when you want them done a certain way. Not all, but enough to make it a great tool.