Meta and AI startup Sierra have launched the Personal Agent Protocol, an open standard for interactions between personal AI agents and businesses, with founding partners including Genesys, Instinct, Rocket, Shopify, Stripe and Walmart. The protocol uses OAuth for authentication, lets users grant agents read or write access to accounts, and allows businesses to control available functions and monitor agent activity through websites, APIs or their own agents. Version 0.1 is planned for release later in October. The initiative comes as Meta’s Muse and other agents such as Instinct gain traction while companies develop competing infrastructure for agent-led commerce. Stripe Link, used by approximately 300 million people and connected to around 1 million merchants, recorded a 38-fold increase in agentic purchases over the month leading into late September 2026. Meta launched Muse on September 8, 2026, as the first personal agent integrated with Stripe Link, later adding Shop Pay and PayPal and introducing purchase protections. Walmart and Shopify also participate in the Universal Commerce Protocol, while Stripe has separately developed protocols with OpenAI and Tempo, leaving the market fragmented.