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Meta, Sierra and partners including Walmart and Stripe announced Tuesday Personal Agent Protocol, a standard its backers say anyone can implement for personal AI agents' authentication and permissions at businesses. Sessions would run on OAuth, an authorization standard; the v0.1 specification is due later in October. Meta's Muse became the top free app on Apple's U.S. App Store a week after launch, before Amazon blocked it for not identifying itself.
“It is kind of chaos until such a standard exists,” said Bret Taylor, Sierra's co-founder and OpenAI's board chairman.
What Changed
- Meta, Sierra and partners including Walmart and Stripe announced Personal Agent Protocol, a standard for how personal AI agents sign in and get permissions at businesses.
- The v0.1 specification is due later in October; no specification, license or governing body has been published yet.
- Amazon cut Meta's Muse agent off from Amazon.com on Sept. 20, saying it did not identify itself while browsing.
- Stripe, Shopify and Walmart already sit in rival agent protocols from Visa, Google and OpenAI, and OpenAI and Anthropic are not on the partner list.
AI-generated summary, reviewed by an editor. More on our AI guidelines.
Amazon blocked Muse
Meta launched Muse on September 8, 2026.
David Singleton, vice president of engineering and consumer products at Meta Superintelligence Labs, said Muse had millions of U.S. users and was “growing rapidly.” That is Meta's own figure and has not been independently verified.
Amazon cut Muse off from Amazon.com on Sept. 20. It said Meta had not told it the agent would access its store, Muse did not identify itself while browsing, and it appeared to capture and store customer credentials. Meta says shared credentials go into secure storage that Muse can use without seeing passwords or payment methods. Meta says Muse runs with its own browser on a secure virtual machine and asks the user before sensitive actions such as sending email or making a purchase.
“We think it's fairly straightforward that third-party applications that offer to make purchases on behalf of customers from other businesses should operate openly and respect service provider decisions about whether or not to participate,” an Amazon spokesperson said.
Amazon sued Perplexity in November 2025 over shopping agents it said were concealed. Its March 2026 preliminary injunction was overturned Aug. 4, when the Ninth Circuit ruled the user was accessing Amazon's computers under federal anti-hacking law, rather than the AI company.
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Walmart, a Muse partner, said problems users reported completing purchases on its site were unintentional. Yelp does not permit non-human traffic unless the agent pays for access through its data licensing program.
How access would work
Taylor compared the proposed standard to signing in to websites with Google or Facebook credentials. He worked on Facebook's sign-in technology as the company's chief technology officer.
Sierra says most personal agents load pages and click through forms as people do. If they cannot complete a task that way, they may call a company's support line or open its web chat.
Under the proposed design, an agent starts on a company's website, discovers what the business offers and begins a session for its user. To ask about a returns policy or check product availability, a guest session may be enough.
For account access, the customer signs in on the company's page or uses credentials already set up with the agent. The customer chooses whether to grant read-only or write access. The business sets the limits on what the agent can do.
OAuth sessions would carry across channels, keeping a question asked before sign-in and an order change made afterward within the same visit. Businesses could let agents use their regular web pages, connect to APIs through MCP and OpenAPI, or work with the company's own agent on a conversational task such as a warranty claim.
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Partners already back rival protocols
Stripe and Shopify have already joined Visa's Trusted Agent Protocol. Walmart and Shopify also participate in Google's Universal Commerce Protocol. Stripe co-developed OpenAI's Agentic Commerce Protocol, released in September 2025.
Google's Universal Commerce Protocol covers the full arc of an agent-initiated checkout. Personal Agent Protocol lists payments, push notifications and finer permissions as future extensions, outside the first specification.
OpenAI and Anthropic are absent from Personal Agent Protocol's partner list. Taylor, who chairs OpenAI's board, said he expected them to participate and would be “really disappointed” if competitors did not use it.
What is still missing
The developers plan design workshops with interested parties and a reference implementation to help businesses and agent builders get started.
No specification, license or governing body has been published yet.
“The whole point of this is to be an open standard,” Taylor said.
Frequently Asked Questions
What is Personal Agent Protocol?
A proposed standard from Meta and Sierra, developed with partners including Walmart and Stripe, that defines how personal AI agents authenticate with businesses and what those businesses let them do. Its backers say anyone can implement it.
How would an agent get access to a customer's account?
The agent starts on the company's website, may begin as a guest, and gets account access only when the customer signs in or uses credentials set up with the agent. The customer picks read-only or write access, and sessions run on OAuth.
Why did Amazon block Meta's Muse?
Amazon said Meta had not told it Muse would access its store, the agent did not identify itself while browsing, and it appeared to capture and store customer credentials. Meta says credentials go into secure storage Muse cannot see.
Does the protocol handle payments?
Not in the first version. Payments, push notifications and finer permissions are listed as future extensions outside the first specification.
Are OpenAI and Anthropic involved?
No. Neither is on the partner list. Bret Taylor, Sierra's co-founder and OpenAI's board chairman, said he expected them to participate and would be "really disappointed" if competitors did not use it.
AI-generated summary, reviewed by an editor. More on our AI guidelines.
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Marcus Schuler
Editor-in-Chief and founder of Implicator.ai. Former ARD correspondent and senior broadcast journalist with 10+ years covering tech. Writes daily briefings on policy and market developments. Based in San Francisco. E-mail: editor@implicator.ai
