"Proof became the first company to put verified legal identity and transaction authorization for AI agents into production with the launch of x401, an open protocol that lets any website ask an AI agent to prove who it's acting for and what that person approved. Proof works with Meta's Muse, ChatGPT dots, Grok, Claude and other assistants that support the Model Context Protocol (MCP). With Proof, a consumer can authorize a wire transfer, approve an itemized purchase or sign a payment mandate through an AI agent."