What the author is asking about, a quick sketchpad where you can try out code quickly and chat with the AI, already exists in the JetBrains IDEs. It's called a scratch file[1].
As far as I know, the idea of a scratch "buffer" comes from emacs. But in Jetbrains IDEs, you have the full IDE support even with context from your current project (you can pick the "modules" you want to have in context). Given the good integration with LLMs, that's basically what the author seems to want. Perhaps give GoLand[2] a try.
Disclosure: no, I don't work for Jetbrains :D just a very happy customer.
It's also available in emacs with packages like gptel which let you send the content of any buffer to your LLM of choice.
I think emacs + LLM is a killer feature: the integration is super deep, deeper than any IDE I've seen, and it's just available... everywhere! Any text in emacs is sendable to a LLM.
I need to try that, but I have a feeling that in emacs it won't work as well because emacs has a bit more "trouble" setting up workspaces and using context only from that. Trying use use `project.el` now as it seems projectile has been superseded by it, if you know how to easily set that up with eglot support + AI would be helpful.
As far as I know, the idea of a scratch "buffer" comes from emacs. But in Jetbrains IDEs, you have the full IDE support even with context from your current project (you can pick the "modules" you want to have in context). Given the good integration with LLMs, that's basically what the author seems to want. Perhaps give GoLand[2] a try.
Disclosure: no, I don't work for Jetbrains :D just a very happy customer.
[1] https://www.jetbrains.com/help/idea/scratches.html
[2] https://www.jetbrains.com/go/