.tex files work fine in VSCode with the Copilot AI integration. Haven’t tried actually writing LaTeX with it but some cursory investigation shows that it seems to be working well. I suspect it’ll perform decently for basic modifications!

(Side note: it’s always impressed me how Copilot works well in even the more obscure languages)

> Unless you want to copy it into another window, tell ChatGPT what modification you want, and then copy it back.

There will be no copying. Plug-ins exist or will exist, such that you will be able to ask GPT-4 directly from within your editor and the plug-in will pass the contents of the document or selection alongside your prompt. Conversely the plug-in for your editor will replace the contents of your document or selection with the output of GPT-4.