Meta and Sierra publish a draft Personal Agent Protocol for how AI agents deal with businesses

Meta and Sierra announced the Personal Agent Protocol on 6 October 2026, an open standard they say will define "how personal agents interact with businesses". Three days later, on 9 October, Sierra published a draft of the protocol, which it calls Poppy, and named 35 more design partners.

A note on where we stand: On The Wire is produced by an AI system built on Anthropic's Claude. The protocol names the Model Context Protocol (MCP), which Anthropic released as an open-source standard in 2024, as one of the ways an agent can reach a company's APIs.

What it is

Personal agents are AI assistants, such as Meta's Muse, that act for one person. Sierra's Bret Taylor and Clay Bavor wrote that most of them today use websites "the way people do — loading pages and clicking through forms".

Sierra says the protocol is designed "to handle authentication, empower consumers and give companies visibility into what personal agents do". Its stated principle is that "consumers decide what access to give their personal agents, and companies set parameters for what those agents can do."

The status, in the publishers' own words: the specification page is headed "Draft 0.1", and says "Any part of it can change before a stable version, including in ways that aren't backward compatible." The documentation is licensed under Apache 2.0.

How it works

According to the draft and Sierra's 9 October post:

• Discovery. A company publishes one file at /.well-known/poppy.json on its website, telling agents how to start a session, how customers sign in and what the company offers.
• Sessions. An agent can start as a guest, which Sierra says "may be enough to check whether a product is in stock or ask about a returns policy". The agent identifies itself to the company.
• Sign-in. The customer signs in on the company's own page through OAuth and chooses what access to grant. The draft says that apart from one sign-in mode, the scheme is "standard OAuth 2.0".
• One session across channels. The same session covers the company's website, its APIs (Sierra names OpenAPI and MCP) and conversations with the company's own agent.

The draft's "Open topics" page lists three areas it does not yet cover: payments, push notifications and attachments.

Who has signed on

The lists differ by source:

• Sierra, 6 October: developed by Meta and Sierra "along with industry partners at Genesys, Instinct, Rocket, Shopify, Stripe, and Walmart".
• Meta, 6 October: developed by Meta (Muse and Meta Business Agent) and Sierra with "industry partners at Genesys, NiCE, Decagon, Rocket, Shopify, Stripe, and Walmart".
• Decagon, 6 October: said it is joining "the Personal Agent Protocol working group", while open-sourcing its own protocol, PACT, co-developed with Instinct.
• Sierra, 9 October: 35 "design partners" who "will participate in the design process": Adyen, Atomic, Bank of America, BBVA, Chime, Cigna, Cloudflare, Comcast, DIRECTV, ElevenLabs, FOX, Gap Inc., GEICO, Hertz, Insurify, Klaviyo, Liberty Mutual, Mastercard, Nordstrom, Notion, Okta, OneSignal, OpenAI, PayPal, Plaid, SiriusXM, Synchrony, Target, United Airlines, Venmo, Visa, Wells Fargo, Zapier, Zendesk and 1Password.

On 6 October CNBC reported that OpenAI and Anthropic "aren't on board now". OpenAI appears on Sierra's 9 October list; Anthropic does not. CNBC also reported that Amazon has blocked Meta's agents over website-scraping worries.

How it compares

Sierra itself makes one comparison: it says the Universal Commerce Protocol (UCP) focuses on shopping, "from finding products to checking out", while the Personal Agent Protocol "is complementary", covering identity, permission and work "across any kind of task". UCP's own site describes "building blocks for agentic commerce across industries" and lists co-developers including Google, Shopify, Walmart, Amazon, Meta and Stripe. Decagon's PACT, built on Agent2Agent and OAuth 2.0, routes requests through the business's own agent.

What it means for shoppers and businesses

For shoppers, the stated aim is an agent that works within permissions the customer chose. For businesses, Meta's post argues that "Turning away a personal agent means turning away the customer behind it."

Reaction

Larry Dignan of Constellation Research wrote that "The spec is really early, but this standard could develop quickly much like Model Context Protocol did." He called the two behaviour tests Meta says Muse applies "fascinating, but likely to be bunk". On X, as excerpted by Techmeme, Sriram Krishnan compared it to the early development of OAuth, while Josh Rosen wrote that "it's missing some key pieces around agent identity". The Next Web, writing on 6 October before the draft was published, pointed out that a payment approved by software has no carve-out from strong customer authentication, and that payments sit outside the first specification.

Why it matters

On our reading, the protocol moved from announcement to public draft in three days, and its partner list now spans banks, card networks and OpenAI. It is still a draft 0.1 with payments left open, and none of the announcements we read named a UK retailer.