Multiple config files of Xcode projects are not publicly documented as far as I remember and personally I have preferred to require my agents not to modify them out of fear it might break something and be hard to fix. I don't know how agentic programming will work in Xcode but I would expect it to do it using a safer approach, so that's also another case where it might have an advantage.

Your workflow looks very interesting especially the describe_ui part, are you already able to do this today?