StepFun's STEPX Neo opened for pre-orders in China on Oct. 13 at 3,999 yuan (about $560, per Decrypt's conversion). The headline feature is not a camera or a chip. It is that the AI agent is part of the operating system, and the phone's own functions are exposed to it over the Model Context Protocol (MCP). That is the part worth a builder's attention: MCP just became the plumbing of a consumer phone, at least according to the company.
Everything below is what StepFun says and what Decrypt reports. The article describes no independent testing, teardown, or hands-on review.
What shipped
Per Decrypt, the phone runs Step AOS 1.0, which the article describes as a mix of Android, Linux, and real-time OS components. The built-in agent is called Amoo. Messaging, files, apps, and settings are exposed as blocks the agent can call, using MCP.
- ▸Two entry points. The usual app grid, plus a separate agent space.
- ▸Two memories. One for user facts and preferences, one for lessons from completed tasks.
- ▸Split compute. Simple commands like setting an alarm run on a small on-device model, some of them offline. Harder multi-app requests go to a larger cloud model.
- ▸A visible agent. A rear MiniLED screen shows what the agent is doing.
Pre-orders ran on JD.com, Tmall, and Douyin, with a first sales event on Oct. 16. The price includes 12 months of the STEPX Token Plan, which Decrypt lists at 100 billion tokens per month. StepFun has not said what the AI costs after year one. The phone was first shown in Shanghai on July 13 without a price or sales date.
The interesting choice: calls, not clicks
Decrypt contrasts this with ByteDance's Doubao phone agent, which relied on screen-reading and simulated taps and drew blocks from major Chinese apps in December. StepFun's route is the opposite. Partners expose capabilities, and the agent calls them.
StepFun says nearly 100 companies and products have signed on, including Alipay, Tencent, Ctrip, Didi, and Meituan. That figure is company-reported. The article gives no contracts and no live integrations, so treat it as a claim of intent until someone shows the calls working.
Here is the pattern we keep seeing in agent stacks. A click-simulating agent works until the app owner objects. A tool-calling agent works because the app owner opted in. The second is slower to build and much harder to shut off. Builders on any chain have already met this fork: scrape a UI, or integrate against a documented tool surface.
What this is not
Be exact about the framing. Decrypt's piece has no crypto, blockchain, or wallet content. Payments, travel bookings, and content creation are still completed on each partner's own platform. Alipay is a partner in the list, and Alipay still does the paying. This is an agent that routes you to checkout, not one that holds funds.
That is the gap an onchain builder should notice. A phone agent that can call MCP tools but cannot hold a wallet, set spend limits, or settle on an open rail is an assistant, not an economic actor. If an agent can move funds, it needs wallet controls, a payment rail, and a way for a counterparty to check what it is. None of that is in this story.
Claimed vs shown
| Claim | Status per Decrypt | |---|---| | Agent built into the OS | Company claim; no independent testing reported | | Nearly 100 partners | Company-reported; no live integrations cited | | 100B tokens/month for 12 months | Company offer; post-year-one pricing not stated | | Price and dates | Match the launch and pre-order listings the article cites |
What to watch
- ▸Third-party MCP tools. Does Amoo only call partner-signed blocks, or can a developer add their own? That decides whether this is a platform or a closed catalogue.
- ▸Post-year-one pricing. A bundled token plan is a launch offer, not a business model.
- ▸Real integrations. Which of the nearly 100 partners ship working tool calls, and how many tasks still hand off to the partner app.
- ▸Any payment path that is not a partner checkout. Wallets and agent-native rails are the missing layer, and nothing here suggests they are coming.
Build with the stack
The phone is a new place for an agent to live. The stack under an agent is the same on any device: the tools it calls, the wallet that limits it, the rail it pays on. Most agent tools start you at a blank prompt. Sato starts with the stack, the skills, MCPs, wallets, and payment rails already mapped and query-able over MCP. Describe the agent and we map what builds it at satohub.ai/build.