VSCode LLM Integration

I've been using ChatGPT-4 a ton lately for coding. It's super useful for small side projects - I can basically act like a PM, telling it what to build. It's less useful for real work where I'm modifying an existing large codebase.

But I still do a lot of copy pasting code from ChatGPT into VSCode and vice versa. Every time I accept new code from it, I need to state my current changes so I can easily see the diff for the new code.

What are the best tools right now for improving this workflow? I've used Copilot, but I want to be able to describe a new feature, have it propose changes to existing files, see the diff, then update the code.