The 2x2 coexistence matrix divides AI capabilities into four quadrants based on 'who does it better' and 'whether it is duplicated': if Joule does it better, retire the custom agent; if the custom one does it better, keep it and document the API contract; if both can do it, make Joule the standard and retire the custom one and redirect calls; if neither does it well, the two sides' contracts clarify who is the source of truth.