Circle and Proof plan to demonstrate a checkout that would give merchants evidence of a buyer’s identity and approval before an AI agent pays in Circle’s dollar-backed stablecoin, USDC.
The companies have set the Las Vegas Money20/20 presentation for Oct. 19-21. In the proposed flow, the merchant would send the agent an identity request through Proof’s x401 protocol and a payment request through x402. Proof’s wallet would supply a claim verifying the buyer and a signature authorizing that order; the agent would then send USDC from a Circle Agent Wallet. The protocols handle separate parts of the exchange: x401 covers identity, while x402 carries payment.
Proof says the merchant could check the credential’s signature and retain signed approval if the transaction is disputed, receiving only the requested identity information rather than a copy of the buyer’s ID. Circle and Proof say the arrangement addresses the difficulty merchants face in confirming that a person approved an order made by an AI agent.
Circle made Agent Wallets available within its AI payment toolkit, Agent Stack, on May 11. Those wallets let developers restrict how much USDC an agent can spend. Proof published x401 on June 25 and said its Oct. 15 production rollout added an agent identity wallet and an MCP server.
The companies have also discussed charging merchants in USDC for each credential verification, with payments going to the identity provider. That potential fee would be separate from the agent’s payment for goods. It could give identity issuers a revenue source while adding a cost for merchants. The companies also identify separate contracting for repeat checks as a friction.
Shopify has described a buyer-controlled checkout for AI shopping agents, where orders cannot proceed until shoppers accept the total and payment method. Circle and Proof plan to run their demonstration through Oct. 21.
