Every hop of the demo: Claude asks Valorian what one request costs, gets a signed quote, checks the budget, pays through Coinbase's wallet with your approval, and Valorian honors the quote when the payment lands. Amber is new. Everything else already ships. Two scenarios: paying for one call, and buying a plan.
The quote: an agent learns a real, per-request price before it commits, signed and valid for a minute, and the 402 honors that exact number. And the plan: an agent with a wallet buys an allowance with one payment, then spends it down at $0 a call. A toll becomes a billing relationship.
The wallet, the approval tap and the settlement rail are Coinbase's. Nothing to build there, and it is more credible that way: the confirmation screen people see is the one they already trust.
USDC on Base mainnet, a real transaction hash, one cent leaving one wallet and landing in yours. The CDR keeps the quote id next to the tx, so quoted and settled can be reconciled.