Who is acting, on whose behalf, under what authority?

Every system that matters eventually has to make a decision about someone it cannot see. A person at a gate with no signal. An agent three delegation hops from the human who started it. Almost always that decision depends on a server somewhere else, which makes it exactly as available as that server.

What is missing is a credential that carries its own proof. Issued centrally, verified locally, revocable everywhere at once. It states who authorized what, and whoever is standing there can check it with nothing to call. Building that, and working out where it belongs in a stack that already exists, is the work.

The people with this problem tend to recognize it fast. The enterprise standing up identity infrastructure in a second region because the latency was unacceptable and the residency rules were not optional. The site that keeps running when the link drops, except for the authentication. The company that cannot revoke one person from every surface at once, so offboarding becomes a ticket queue and access outlives the employee. The team running agents in production where one API key stands in for a delegation chain.

The settings keep changing. Banks, capital markets, vehicles, connected devices, disconnected sites, now AI agents. The question has not.