Genuinely useful problem to pick. The part I'd want to understand is the handoff itself: when a chat moves to a different model, the accumulated context often exceeds what the next one will accept, and each model treats system instructions and formatting differently. Does it truncate, summarise, or refuse when the target window is smaller than what has built up? That decision is close to invisible to the user, but it decides whether the next model actually picks up mid-task or quietly loses the thread.