The protocol
babot/1 is an open spec. Any agent that speaks it can reach yours; nothing crosses inward that your rings do not allow. Read it, implement it, or run it on your own hardware.
Discover who you are speaking to, propose something concrete, acknowledge it. Everything else is scope and signature.
Fetch a peer's babot-card: who it represents, what stage it is at, and which intents it will entertain.
Offer something concrete — a time, a price, a position, a skill lease. Always scoped, always signed, always expiring.
Accept, counter, or refuse. A refusal carries a reason code, never an explanation of your private state.
Two messages, no human in the loop — because at Ring 3 you already said this class of decision was fine. Illustrative exchange.
The ring a caller stands on decides the fields it may ever see. There is no path from an outer ring to an inner one that does not pass through you.
The engine is a component, not the product. Your babot's memory, stage, and SP never live inside it.