I've been dealing with it on the post-training (runtime) side with a large codebase that contains many moving parts, many rules and requirements. Putting all of that into the context has already gone far past 1MB, so it's untenable.

Now I have all of that information stored in a pointers-to-resources fashion, where layers of small "directories" of triggers-to-information point the agent gradually towards deeper, more esoteric knowledge the more specific its needs become when tackling a goal.