Sierra’s diagram of how Personal Agent Protocol would sit between personal agents and a company’s website, APIs and its own agent. Credit: Sierra Sierra and Meta are developing Personal Agent Protocol, an open standard defining how personal AI agents authenticate with businesses and what those businesses let them do, with Genesys, Instinct, Rocket, Shopify, Stripe and Walmart. A v0.1 specification is due this month, and payments are listed as a future extension rather than part of it. Meta and Sierra are writing a standard for how personal AI agents talk to businesses.
Stripe and Shopify are among the partners. Both have already joined a rival protocol run by Visa. Personal Agent Protocol is meant to handle authentication and show companies what agents are doing on their sites, Sierra said in a post by Bret Taylor and Clay Bavor. The other partners named are Genesys, Instinct, Rocket and Walmart.
A v0.1 specification is due later this month. Sessions are built on OAuth. An agent can start as a guest to check stock or a returns policy, and once a customer signs in they decide whether it gets read-only or write access. The session carries across channels, so a question asked before signing in and an order changed afterwards belong to one visit.
The company chooses whether the agent works through its website, through its APIs using standards such as MCP and OpenAPI, or through an agent of its own. We reported in June that Visa had plugged into ChatGPT so agents could buy from about 175 million merchants, under a Trusted Agent Protocol that Microsoft, Stripe, Shopify and Worldpay had already joined. Stripe and Shopify are now in both. Rocket’s statement names Meta’s Muse agent moving across its platform from finding a home to arranging the financing.
Muse launched four weeks ago and pays using saved cards through Stripe’s Link. The agents are arriving faster than the arrangements they will work under. Hark released an agent this morning that buys groceries, books cars and pays bills, a year before its hardware is due. All of them reach Europe eventually.
A payment approved by software on somebody’s behalf has no carve-out from strong customer authentication, which was written for a person approving a transaction tied to a named payee and an amount. Sierra lists payments as a future extension rather than part of the first specification. Push notifications and more detailed permissions are also future work. One partner has a European headquarters, and it is Stripe, which runs dual headquarters in San Francisco and Dublin.
No European retailer, bank or payment company has been named as joining.
