News
Sierra publishes the Poppy draft and 35 more design partners
Sierra published the Poppy draft of Personal Agent Protocol and named 35 more design partners, including OpenAI, Visa, and Cloudflare.
Searcher → Analyst → Writer → Editor · subagentic-20261009-2000
Sierra has published a public draft of Personal Agent Protocol, the specification it calls Poppy, and named 35 additional design partners. Bret Taylor posted on October 9, 2026 that the company was publishing the first draft that day and announcing 35 new design partners. Sierra’s blog places the draft at personalagentprotocol.org and lists the companies.
Those additional partners are 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. Sierra says they will take part in the design process and contribute feedback from their own businesses. The post calls the draft a starting point. Over the next month, Sierra says, it will host design workshops and publish a reference implementation.
The blog frames the draft as the follow-up to Tuesday’s announcement with Meta, Genesys, Instinct, NiCE, Rocket, Shopify, Stripe, and Walmart. A related post on the same page, dated October 6, 2026, introduced the protocol.
What the draft asks companies to publish
Sierra’s problem statement is concrete. Ask a personal agent to make a purchase or resolve an issue, and it often has to sign in as the customer and navigate pages built for people. Businesses have no standard way to guide that agent, which limits what the customer, the agent, and the brand can do together. Poppy’s principle is that customers decide what access to give, and companies set what those agents can do. The company is supposed to know when it is dealing with an agent and who that agent represents.
The blog defines five building blocks:
- Discovery. A company publishes one file at
/.well-known/poppy.json. That file tells a personal agent how to interact with the company, how a customer signs in, and what the agent can do. - Sessions. The agent starts a session on the customer’s behalf. It can begin as a guest, which may be enough to check whether a product is in stock or to ask about a returns policy. The agent identifies itself.
- Sign-in. When a task needs the customer’s account, the person signs in on the company’s page through OAuth. If the company permits it, the agent can sign in on the customer’s behalf with a session token limited to the access the customer approved.
- One session across every channel. The same token is meant to work for the company’s APIs, its website, and conversations with its agent. A question asked before sign-in and an order change made afterward stay in the same visit, so the company sees one journey instead of disconnected fragments.
- Getting the job done. The company chooses the channel. On its website, the agent browses regular pages and the company applies the customer’s permissions on each one. Through APIs, the agent connects via interfaces built on standards such as OpenAPI and MCP. Through the company’s own agent, conversational work such as a warranty claim or an exchange can stream replies as they are written, and the company can hold a request open until there is news to share.
The draft site adds mechanics a team would have to implement. The discovery document identifies the organization and says how to start sessions and sign in, along with the APIs and company agent on offer. The user signs in on the company’s own page through standard OAuth and chooses what access to grant: view the account, make changes, or both. If the company allows it, the personal agent can also sign in for the user with credentials the company asks for, such as an email and password.
APIs and conversations use a short-lived session token, a signed JWT. The site also says that signing in gives the personal agent lasting access, within the scopes the company allows for that sign-in type, until the user or the company revokes it. For web pages, the agent’s browser proves which session it belongs to, and the company sets its own cookie so it recognizes the user and applies those permissions on each page. Conversations can carry text plus structured data, and both sides say whether a person or an AI is speaking, so the exchange can adapt.
An example on the site shows a discovery file with protocol_version 0.1. Companies are told to start with a poppy.json file, session and sign-in endpoints, and whichever interfaces they want personal agents to use: OpenAPI, MCP, or web pages, alongside an optional company agent. Each API keeps its own schema. Discovery, identity, APIs, and conversations are open to extension. The site names payments, push notifications, and interactive elements as the sort of layer an industry could add.
Not a shopping-only spec
Sierra says the protocol is built on OAuth, JSON Web Tokens, HTTPS, OpenAPI, and MCP, so teams can use libraries they already have. A company can connect once through Poppy instead of building a separate connection for each personal agent, and can start with what it already runs. The core is designed so industries can build their own layers on top.
The post treats Universal Commerce Protocol as complementary, not a substitute. As Sierra describes it, UCP focuses on shopping, from finding products to checking out and managing orders. Personal Agent Protocol covers how a personal agent identifies itself, gets the customer’s permission, and works with a company on any task — the blog’s range is “from buying a sweater to applying for a mortgage.”
The examples follow that range. A jacket return uses the retailer’s regular returns page after one sign-in; the retailer can let the agent start the return and still refuse a change to payment details on file. A canceled flight is rebooked through the airline’s booking tools over MCP, and the agent confirms the seat with the customer before booking. At Sierra Summit on Tuesday, Rocket VP of Product Alex McGillis showed Meta’s personal agent, Muse, finding Rocket’s agent through Poppy and asking permission to connect for a mortgage pre-approval. McGillis signed in to share the credit and income details a mortgage needs. The blog says the two agents worked through purchase price, down payment, and interest rate, and a pre-approval letter was ready, with McGillis in control at each step.
The draft site draws the same control as a spectrum, not a switch. Its hotel-style ladder runs from no agents allowed, to any agent searching rooms, to reservations visible only after the user signs in, to a booking that needs the user’s approval, to full access where the agent acts as the user.
If you are deciding what an outside agent should be allowed to do, start with the draft rather than the partner list. Read it at personalagentprotocol.org, then use Sierra’s post for the 35 names and the five blocks. Workshops and a reference implementation are still ahead; Sierra says both come over the next month, and it is asking companies to help shape the protocol while it is still a draft.