Anything it has not been trained on. Try getting AI to use OpenAI's responses API. You will have to try very hard to convince it not to use the chat completions API.
in cursor you can index docs by just adding a url and then reference it like file context in the editor
yeah once again you need the right context to override what's in the weights. It may not know how to use the responses api, so you need to provide examples in context (or tools to fetch them)
im struggling to understand what the issue with that is
This is just an issue with people who expect AI to solve all of lifes problems before they get out of bed not realising they have no idea how AI works or what it produces and decide "it stops working because it sucks" instead of "it stops working because I don't know what I'm doing"