Tencent-Backed Startup StepFun Debuts AI-First Smartphone

Chinese artificial intelligence startup StepFun is challenging conventional mobile design with the release of the STEPX Neo, a smartphone built entirely around an autonomous software agent rather than a grid of applications. Backed by tech giant Tencent, the company opened pre-orders for the new device at 3,999 yuan, equivalent to about $560, ahead of its initial sales event.

Unlike traditional mobile operating systems such as iOS or Android, where artificial intelligence functions primarily as an assistant living inside applications, StepFun has embedded its agent directly into the foundational software. The company previewed the hardware and its proprietary Step AOS 1.0 software in Shanghai earlier this year, arguing that legacy smartphone systems were never designed for autonomous task execution.

The Agent-First Approach

The core interface revolves around Amoo, an AI agent designed to execute complex user goals without requiring manual navigation through multiple applications. For instance, rather than opening a ride-hailing service, entering a destination, and selecting a vehicle, users simply state their travel intentions to the device, and the agent manages the remaining steps.

Step AOS 1.0 combines elements of Android, Linux, and real-time operating systems into a base layer featuring long-term memory, task scheduling, and security controls. The software divides standard phone functions like messaging, files, and settings into modular blocks that the agent can access directly. This integration utilizes the Model Context Protocol, a shared standard that allows artificial intelligence programs to connect seamlessly with other software.

Under the hood, the system balances processing power by routing simpler commands to a small model running locally on the phone, while heavier requests spanning multiple platforms are sent to a cloud-based large language model. The hardware itself features a secondary MiniLED screen on the back to display Amoo's current activities in real time.

Ecosystem and Infrastructure

StepFun was founded in 2023 by former Microsoft vice president Jiang Daxin and develops its own large language models. The company's flagship model, Step 5 Preview, incorporates 600 billion parameters and a massive context window capable of processing up to one million tokens at once. Buyers of the STEPX Neo receive a 12-month subscription to the STEPX Token Plan, providing 100 billion tokens per month.

To ensure practical utility, nearly 100 companies and products have aligned with the ecosystem. Major Chinese platforms including Alipay, Tencent, Ctrip, Didi, and Meituan will continue to process payments, travel bookings, and content creation through their own systems while interacting directly with the StepFun agent.

Why it matters

The launch marks a notable attempt to shift the smartphone paradigm away from app-centric interfaces toward autonomous software agents. By integrating artificial intelligence at the operating system level, StepFun is testing whether consumers prefer conversational task execution over traditional screen navigation. The backing of major Chinese tech platforms suggests that dominant service providers are willing to experiment with agent-driven architectures.

What to watch

Observers will monitor consumer adoption rates following the initial sales events and evaluate how effectively the Amoo agent handles complex, multi-app workflows. Additionally, market analysts will look for clarity on subscription pricing for the token plan after the initial 12-month promotional period expires.