StepFun's Step AOS: An Agent-Native Operating System, Not "OS Plus AI"

On July 13, 2026, the Chinese AI company StepFun held a launch event in Shanghai and unveiled a stack of new products at once. The headline release is Step AOS, which the company calls the world's first agent-native operating system. On top of it sit a personal AI assistant called Amoo, a new device brand called STEPX, and the first phone built for the new stack, STEPX Neo. The key idea is a shift in paradigm. Today's smartphones run a traditional operating system that was designed for humans tapping on apps, then bolted an AI assistant on top. StepFun argues this is the wrong starting point. Step AOS is rebuilt from zero so that the operating system itself treats the AI agent as a first-class citizen, not as a visitor that must ask the OS for permission at every step. The system is built around three new capabilities. First, a two-domain, three-step memory structure helps the agent remember a user's habits and its own experience, and reaches top scores on international memory benchmarks, with a routine recall time of about 15 milliseconds. Second, an edge-cloud multi-brain layer lets simple tasks finish on the device in under 100 milliseconds with over 99 percent success, while complex tasks are sent to the cloud. Third, the team pairs the launch with a four-part safety framework, summarized as trusted, visible, controllable, and reversible. STEPX Neo is also the first phone to pass China's L3 national standard for AI terminals, the highest level currently open for testing. The launch partner list includes Ctrip, Alipay, Didi, Meituan, WPS, and CapCut, hinting that the next round of competition will not be about who has the smartest model, but about who controls the operating system on which all agents run.