Sixteen days after Amazon began blocking Meta’s Muse agent from its retail site, Meta and Sierra announced an open standard for how personal AI agents deal with businesses. The Personal Agent Protocol (PAP) arrived on October 6, 2026 with Walmart, Shopify and Stripe on its partner list and no specification attached. Sierra says the v0.1 spec will follow later this month.
What Sierra and Meta announced
Sierra co-founders Bret Taylor and Clay Bavor introduced PAP as an open standard that Meta and Sierra are developing with Genesys, Instinct, Rocket, Shopify, Stripe and Walmart. It covers authentication, consumer control and company visibility when an agent acts through a website, an API or a company’s own agent. Meta’s partner list, as CMSWire reported it, adds NiCE and Decagon and leaves out Instinct.
The backdrop is Muse, the personal agent Meta announced on September 8. Amazon began blocking it on September 20, and an Amazon spokesperson said that apps buying on customers’ behalf should operate openly and respect the choices of the businesses they shop. Adweek relayed a further Amazon claim, that Muse does not identify itself. That claim comes from Amazon and has not been independently verified. Meta’s October 6 post, which acknowledged that some businesses have blocked personal agents, put its argument in one line: “Turning away a personal agent means turning away the customer behind it.”
How a session works
Sierra’s design starts at the company’s website. An agent discovers what a business offers from there and can begin as a guest, for example to check stock or a returns policy. For account tasks, the customer signs in on the company’s own page or uses credentials already set up with the agent, and chooses read-only or write access. Sessions run on OAuth and carry across channels, so a question asked before sign-in and an order change made afterward belong to the same visit.
Businesses pick from three routes: ordinary web pages, APIs built on standards such as MCP and OpenAPI, or the company’s own agent, which Sierra points to for conversational tasks like a warranty claim. The examples reach well past shopping. Rocket Companies CTO Shawn Malhotra said Rocket and Redfin are building agents that can move from home search to financing.
Payments wait for a later version
Sierra’s post lists three possible extensions: more detailed permissions, push notifications such as a delayed-flight alert, and payments. Each is described as something that could come, with no dates attached. The payments extension could let an agent complete a purchase without sharing card details.
Three earlier efforts center on buying. OpenAI’s Agentic Commerce Protocol (ACP), co-developed with Stripe and open-sourced on September 29, 2025, carries order details from ChatGPT to a merchant’s backend. Visa’s Trusted Agent Protocol (TAP), built with Cloudflare and announced October 14, 2025, uses cryptographic signatures so merchants can recognize approved agents, with Shopify and Stripe among its early partners. Google’s Universal Commerce Protocol (UCP), announced January 11, 2026, was co-developed with Shopify, Etsy, Wayfair, Target and Walmart and spans discovery through post-purchase support.
The same names keep appearing. Stripe is a partner in PAP, a co-developer of ACP, an early partner in TAP and an endorser of UCP. Shopify sits in PAP, TAP and UCP, and Walmart in PAP and UCP.
My take: leading with identity and permissions is the sounder order. A payment standard is only as useful as a merchant’s confidence about who is asking and what that party may do, and PAP puts the customer’s read-only or write choice at the front of the design. The catch is that none of this can be tested until the spec exists.
A published spec already exists next door
Decagon, which Meta lists as a partner, published its own Personal Agent Consent & Trust Protocol, PACT, on the same day. Decagon says PACT is built on the Agent2Agent protocol and OAuth 2.0, was co-developed with Instinct, and has its spec at openpactprotocol.org/spec. Decagon also says it is joining the Personal Agent Protocol working group announced by the team behind Muse.
Instinct therefore appears on both sides: Sierra says it is joining PAP, and Decagon says it co-developed PACT. The shared membership suggests the two efforts could converge rather than compete, though that is an inference. The v0.1 text will show how much of PACT’s approach carries over.
What the announcement leaves open
Membership is still moving. The Daily Caller News Foundation, citing CNBC, reports that Taylor expects both OpenAI and Anthropic to sign on, and describes Taylor as OpenAI’s chairman. OpenAI already backs its own commerce protocol, so its choice would say a good deal about how the field settles.
Governance is the larger gap. Sierra’s announcement names no governing body, licence or standards organization. It says the protocol is open for anyone to implement and builds on OAuth, MCP and OpenAPI. Open for implementation describes who can build against a protocol. It does not say who decides how the protocol changes.
Agent identification is the third. Sierra’s post explains how customers sign in and set permissions, but Amazon’s stated complaint was that Muse does not say who it is. Whether v0.1 gives a business a way to confirm which agent is calling will matter as much as the sign-in flow.
When the spec arrives, three things will show whether PAP is a standard or a partner announcement: the licence and governance terms, the mechanism for identifying an agent, and how the text treats PACT. Until then, PAP is a plan with a long partner list.
The post Meta and Sierra’s Personal Agent Protocol Starts With Login, Not Payments appeared first on DataFLOQ.
