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How we got to the Personal Agent Protocol

PAP didn't appear out of nowhere. Meta launched Muse on September 8, 2026. Amazon blocked it twelve days later. Just over two weeks after that, Meta and Sierra announced a standard for exactly that problem: agents showing up at businesses without saying who sent them.

The earlier entries matter too. By the time PAP arrived, agents already had a checkout protocol (ACP), an identity protocol (TAP) and a commerce protocol (UCP). PAP's pitch is the piece none of them owns: the customer's permission.

  1. Context

    OpenAI and Stripe release the Agentic Commerce Protocol

    ACP powers Instant Checkout in ChatGPT. Stripe issues a shared payment token so the agent never sees the card. Stripe is now also a PAP launch partner. Stripe

  2. Context

    Visa and Cloudflare introduce the Trusted Agent Protocol

    TAP lets merchants tell a known agent from an anonymous bot by checking signed HTTP requests, building on Web Bot Auth. Visa Developer

  3. Context

    Amazon sues Perplexity over its shopping agent

    Perplexity called the suit a bullying tactic. It set the tone for how big retailers treat agents that show up uninvited. CNBC

  4. Context

    Google announces the Universal Commerce Protocol

    UCP covers the shopping flow from discovery to checkout and post-purchase. Shopify helped build it. Google Developers Blog

  5. Context

    Meta launches Muse

    Meta’s personal agent books trips, fills in forms and buys things for its users, in the US first. Engadget

  6. Context

    Amazon blocks Muse on Amazon.com

    Amazon says Meta declined to remove Amazon from the Muse experience, and that the agent didn’t identify itself while browsing. BERI

  7. PAP

    Sierra and Meta announce the Personal Agent Protocol

    Unveiled at Sierra Summit in San Francisco. OAuth sessions, guest or signed-in, read-only or write access, and three routes the company can offer. Sierra (Bret Taylor, Clay Bavor)

  8. PAP

    Two partner lists, not one

    Sierra names Genesys, Instinct, Rocket, Shopify, Stripe and Walmart. Meta’s list swaps Instinct for NiCE and Decagon. CMSWire

  9. PAP

    Decagon open-sources PACT and joins the PAP working group

    PACT, built with Instinct on A2A and OAuth 2.0, ships with a public spec the same day PAP is announced without one. Decagon

  10. Expected

    PAP v0.1 specification (expected)

    Promised for later in October, followed by design workshops and a reference implementation. Sierra (Bret Taylor, Clay Bavor)

Next stop is v0.1. We track it on the spec status page.

Sources

  1. Stripe powers Instant Checkout in ChatGPT and releases Agentic Commerce Protocol codeveloped with OpenAI · Stripe, Sep 29, 2025 · primary source
  2. Getting Started with Visa's Trusted Agent Protocol · Visa Developer · primary source
  3. Meta joins with group of companies to tame 'chaos' of doing business with AI bots · CNBC, Oct 6, 2026
  4. Under the Hood: Universal Commerce Protocol (UCP) · Google Developers Blog · primary source
  5. Meta reveals its AI agent that can shop, send emails and plan trips on your behalf · Engadget
  6. Meta's Personal Agent Protocol Signs Walmart Before It Has a Spec · BERI
  7. Introducing Personal Agent Protocol · Sierra (Bret Taylor, Clay Bavor), Oct 6, 2026 · primary source
  8. Genesys, NiCE Join Sierra, Meta on Open Standard for Personal AI Agents · CMSWire
  9. Introducing the Personal Agent Consent & Trust Protocol (PACT) · Decagon, Oct 6, 2026 · primary source

pap.md is independent and not affiliated with Sierra, Meta or any PAP partner. Facts here come from the sources listed on each page.