StepFun unveils STEPX Neo, betting protocol-based access can bridge app silos
StepFun released STEPX Neo on July 13, positioning it as the world’s first native large-model agent smartphone. The device runs Step AOS, includes the Amoo agent, and comes with the company’s Step Edge on-device model and GUI-MCP protocol. The product arrives after a very different experiment by ByteDance’s Doubao phone assistant ran into WeChat risk controls in late 2025, highlighting how hard cross-app automation remains inside closed mobile ecosystems. The key distinction is technical and commercial. Doubao relied on simulated taps through system-level permissions, a method that could bypass splash screens and jump across apps but also triggered platform defenses and, according to the article, raised sustainability and compliance questions. StepFun is trying another route: a standardized interface model that asks apps to expose capabilities instead of having an agent imitate user actions from the outside. StepFun says GUI-MCP uses a layered dual-stack architecture, keeps raw screenshots on the device, uploads only semantic summaries, and works with a 4B GUI-specific model that supports recognition and operation across more than 200 apps locally. The broader question is whether major apps will join. StepFun has named partners including Meituan, WPS, CapCut, Ctrip, Amap, Alipay, Baidu, Didi, and JD.com, but the article argues that technical design alone will not break app walls unless revenue sharing and authorization models also change.








