That makes it not a context window.
How to organize code like you said, and how agents interact with it, to keep the actual context window small is the fundamental challenge.
I keep getting surprised that people who are all-in on this (" i regular execute tasks that require hundreds of subagents ") don't have any idea of what is happening even a single layer below their interface to the LLM ("in practice the context window is effectively unlimited or at least exceptionally high — 100m+ tokens.")
I looked at that response by GP (rgbrenner) and refrained from replying because if someone is both running hundreds of agents at a time AND oblivious to what "context window" means, there is no possible sane discourse that would result from any engagement.
ok "series of context windows spread across many agents".. sure much clearer.
Doesn't change my point: the amount of code the agent can operate on is very large, if not unlimited, as long as you put even a little bit of thought into structuring things so it can be divided along a boundary.
If you let the codebase degrade into spaghetti, then the LLM is going to have the same problem any engineer would have with that. The rules for good code didn't disappear.