I've been in a lot of situations where I could step gpt5.x through a big refactor if I spoon feed it one type name at a time. If I let it try to do the whole thing at once it will refuse or get stuck in apply patch loops.

Planner / executor separation can make a huge difference in performance. LLMs are fantastic at coming up with a lot of elaborate narratives regarding what should be done. They are terrible about doing that prescribed work all at once. This impedance mismatch is best resolved with a simple role separation. Placing a shared collection of tasks between these roles is how you can decouple them. The executors need significantly more tokens than your planners to get the job done. It's probably in the range of 10-100x more for really complicated jobs with a lot of iterations through compiler feedback, sql provider errors, etc. This is why you can't do both things in the same context very well.