StepFun ditches the app drawer, bets the phone on an AI agent — and a 3,999 yuan receipt 🤖

StepFun, a Chinese AI startup backed by Tencent, has launched the STEPX Neo, a smartphone whose AI agent is built directly into the operating system rather than living inside an individual app. Pre-orders opened at 3,999 yuan (about $560) with a first sales event scheduled for Oct. 16. StepFun told the launch audience that in the agent era AI is no longer an add-on to a smartphone but the product itself.

The device runs Step AOS 1.0, which StepFun says was built from scratch for autonomous task execution and combines Android, Linux, and real-time operating system components. The system breaks messaging, apps, files and settings into modular blocks the agent can call directly through Model Context Protocol (MCP), a shared standard that lets AI programs plug into other software. Users can access either a familiar app grid or a separate agent space headed by an assistant called Amoo, which maintains separate memory stores for user facts and learned task routines.

Simple commands such as setting an alarm run on a small on-device model, some of them offline, while multi-app requests are routed to a larger cloud model. A secondary MiniLED display on the rear of the device shows Amoo's real-time activity. StepFun first previewed the agent, the operating system and the STEPX brand in Shanghai on July 13, without pricing or a sales date.

Nearly 100 companies and products, including Alipay, Tencent, Ctrip, Didi and Meituan, have integrated with the platform, allowing payments, travel bookings and content creation to remain on their native services rather than relying on screen-reading or simulated-click techniques. The 3,999-yuan package includes 12 months of the STEPX Token Plan, providing 100 billion tokens per month, though it has not disclosed AI service costs after the first year.

StepFun, founded in 2023 by former Microsoft vice president Jiang Daxin, develops its own large language models. Its flagship Step 5 Preview launched in September with 600 billion parameters, of which 27 billion are active at a time, and can process up to 1 million tokens in a single request. A smaller Step 3.5 Flash, released earlier this year, is available as open-source under an Apache 2.0 license.