If the tool/agent distinction exists for sufficiently powerful AI, then a theory of friendliness might not be strictly necessary, but still highly prudent.

Going from a tool-AI to an agent-AI is a relatively simple step of the entire process. If meaningful guarantees of friendliness turn out to be impossible, then security comes down on no one attempting to make an agent-AI when strong enough tool-AIs are available. Agency should be kept to a minimum, even with a theory of friendliness in hand, as Holden argues in objection 1. Guarantees are safeguards against the possibility of agency rather than a green light.