Phone Harness MCP is a hosted connector for people already running agents in Claude, ChatGPT, Cursor, Codex, or another Model Context Protocol client. Paste the server URL, sign in, and the agent can read the screen, tap, type, swipe, and open apps on a cloud phone. Nothing has to be installed on the machine running the agent: no Mac, no adb, and no pairing. The release matters now because those clients already speak MCP, while the existing Phone Harness path still needs a local iPhone Mirroring session on a Mac or an adb connection to a personal Android. Cloud iPhones are dedicated real phones on a flat subscription, $80 a month or $100 with an eSIM, and 20% off when billed annually. Android sessions run on emulators, free to start and then 5 cents a phone-minute, and new accounts begin with $5 of credit. A live viewer stays open while the agent works, and saved phones keep apps and logins between sessions. On ChatGPT web, a custom connector that can drive the phone requires a Business, Enterprise, or Edu workspace. Shawn Pana is the solo founder and CEO. Phone Harness is in Y Combinator's Fall 2026 batch in San Francisco, and he was previously head of growth at Browser Use. Y Combinator lists the open-source project at more than 3,800 GitHub stars. The local harness is still how an agent attaches to a phone someone already owns. This launch is the hosted MCP path onto a phone the agent can use without that hardware.