Sierra and Meta have launched the Personal Agent Protocol, an open standard for how personal AI agents interact with businesses. The announcement was made on October 6. Founding partners include Walmart, Shopify, Stripe, Genesys, Instinct and Rocket.

The protocol defines how agents authenticate with businesses and what they are allowed to do. It is built on OAuth. Agents can act as guests for simple tasks like checking stock. Once users sign in, they decide whether the agent gets read-only or write access. Sessions carry across channels, so one visit stays connected.

Businesses can choose how agents reach them. Options include websites, APIs like MCP and OpenAPI, or their own agents. Sierra plans to publish a v0.1 specification later in October. Design workshops and a reference implementation will follow.

The move follows Meta’s launch of Muse, its personal AI agent, a month ago. Notably, Amazon, OpenAI and Anthropic are not part of the coalition. Visa launched a rival agent protocol in June.