StepFun Launches STEPX Neo, China's First Vertically Integrated AI Agent Smartphone

Shanghai-based AI unicorn StepFun launched its first AI agent smartphone, the STEPX Neo, on July 13, alongside the Step AOS agent-native operating system and the Amoo personal agent¹. The device combines StepFun's own foundation models, an operating system designed from scratch for agent interaction, and custom hardware, representing the most complete vertically integrated AI-native smartphone offering from a Chinese AI company.

StepFun has secured ecosystem partnerships with more than 10 major internet platforms including Alipay, Meituan, Amap, Tongcheng, Jianying, JD, Didi, Baidu, Weibo, and WPS for cross-app service invocation³. Chairman Yin Qi said StepFun does not prioritize shipment volume in the first phase but aims to get early users onto the platform as quickly as possible.

Step AOS is built on three architectural pillars. First, a dual-domain three-stage memory system separates user-domain personal data from agent-domain knowledge, processing information through recording, organization, and recall stages. Second, an end-cloud collaboration architecture routes simple tasks like setting alarms or finding photos to on-device inference using the Step Edge model family, while complex long-chain tasks are handled by cloud models up to 1.5 trillion parameters. Third, an atomic service engine decomposes traditional app functions into agent-callable micro-services, enabling cross-app task execution without requiring individual app integrations for each operation.

The Step Edge model family achieved top rankings across all 29 benchmark evaluations for on-device edge models globally and took first place in GUI, agent, and terminal task benchmarks in China. The Step Inference NPU engine optimizes inference specifically for terminal hardware.

Step AOS includes a security architecture with trusted execution environments for agents, fully auditable and trackable operations, on-demand permissions revoked when tasks complete, and one-click reversal for erroneous operations.

Yin Qi said applications will not disappear but will evolve to serve more diverse carriers, with agents becoming a new application paradigm alongside apps and websites. StepFun is also recruiting 1,000 creators through a co-creation program with Bilibili to build agents on the platform. The company plans a second-phase launch in 100 days with additional agents, skills, and ecosystem partners built with early users.

The launch arrives amid emerging competition. ZTE subsidiary Nubia will debut its own AI agent phone on July 17 at the World Artificial Intelligence Conference. Nubia president Ni Fei outlined a vision where native agent phones understand user intent, remember preferences, execute complete tasks across apps, and protect privacy. The upcoming device marks Nubia's second AI phone generation after the December 2025 nubia M153 engineering prototype with ByteDance Doubao. However, Nubia and ByteDance's pilot showed that early agent performance was inconsistent, with some demo scenarios not reliably reproducible.

StepFun's foundation models span from 300M to 400B parameters, and its end-cloud architecture routes tasks to models as large as 1.5 trillion parameters. ANALYSIS StepFun's vertical integration — spanning its own foundation models, a custom OS, and hardware — contrasts with Nubia's approach of pairing its own device engineering with a third-party model ecosystem.

The broader market context adds urgency: IDC data shows Chinese smartphone shipments declined 3.3% year-on-year in Q1 2026. China's National 15th Five-Year Plan explicitly targets over 90% adoption of new-generation intelligent terminals by 2030.

ANALYSIS The STEPX Neo launch and Nubia's imminent debut signal that the AI agent smartphone category is moving from concept to commercial product in China, with both a pure-play AI company and a traditional hardware maker now competing for the same emerging segment.