>> I don't think people realize how much dumber the models get at larger contexts and how much more the token cost is.

It does not match my experience that the model gets significantly dumber. It does get slower and more expensive, yes, but that's a sacrifice that needs to be made when working on anything complex.

My process involves having the main agent use subagents to explore what is needed for the given task. Then it writes a plan. Then it has the plan adversarially reviewed by more subagents and hardens it. After all is said and done, the 1M token window is 30-40% full. This flow would never work with 272k context, and in fact I've had to tone it down significantly for 5.6 Sol. Which, now that I think about it, probably explains why the results I get with it are inferior.