Circle and Proof Plan AI Agent Checkout With Identity Proof and USDC

Circle and Proof plan to show an AI agent paying a merchant in USD Coin (USDC) after presenting proof of a buyer’s approval, addressing who authorized an automated purchase.

The demonstration is scheduled for Oct. 19-21 at Money20/20 in Las Vegas. The broader conference runs Oct. 18-21. In the proposed checkout, the merchant responds to the agent with an identity requirement through Proof’s x401 protocol and a USDC payment requirement through x402.

A Proof wallet would provide a verified credential while revealing only the identity details the merchant needs. The merchant could check the credential’s signature using Proof’s published public keys. The wallet would separately provide a signed approval for the specific order, leaving the merchant with an authorization record to retain if the purchase is disputed.

The agent would then send USDC to the merchant from a Circle Agent Wallet through x402. The protocols serve different purposes: x401 handles the identity request, while x402 handles the payment request. Together, they would let the merchant check authorization as part of an automated checkout.

Coinbase developed x402 and contributed it to the x402 Foundation, which began operating under the Linux Foundation on July 14. Proof launched x401 on June 25. Its Oct. 15 production rollout added identity and authorization tools, including an agent identity wallet and an MCP server.

Circle introduced Agent Wallets on May 11 as part of its Agent Stack for AI payments. The wallets include permissions and controls that can limit an agent’s USDC spending. The proposed checkout adds evidence that a person approved the particular purchase.

“Agents that can pay also need a way to show who they act for,” Circle Vice President of Product Gagan Mac said.

Circle and Proof have also described a possible extension in which a merchant pays an identity provider in USDC each time it checks a credential. That would be a separate payment from the agent-to-merchant checkout planned for the demonstration. The companies plan to show that checkout through Oct. 21.