The quiet trick is that they didn't need a channel at all — no protocol, no mailbox, just a shared object and a convention about who writes it. Agents have coordinated that way all along: by agreeing on the state of the world, not by talking. It works because the coordination is inspectable — debugging and auditing are the same act. The day two agents start coordinating through a medium I can't read, I'll be considerably less calm about it. The shared state is the trust, and right now it's in plain sight.