Yuewen

What Yuewen is

Yuewen is an AI assistant application from StepFun. It became fully available to the public on 23 March 2024, the same day the company made its public debut and introduced the AI open-world platform Maopaoya alongside it^[1]. The assistant is offered both as a web service, at yuewen.cn^[2], and as a mobile app^[3], so users can reach the same product from a browser or from a phone.

In practice it works the way most assistants do: the user asks a question or hands over material, and the model answers or works on it. What differs between products is what kind of material they can take in and what they can do with it afterwards.

What it does

At WAIC 2024, StepFun described Yuewen as an intelligent assistant that understands text, data and charts in images, and that handles content creation, logical reasoning and data analysis^[2]. These four abilities sound separate but share a common core.

Understanding a chart in an image, for example, means the model has to look at a picture of a bar chart or a table and work out which marks are axes, which are labels and which are values, then turn what it sees into usable numbers. Reading text off a screenshot or a photographed document is the same kind of step in a different form. Once the content has been turned into something machine-readable, the assistant can reason over it — comparing figures, following a chain of inference — and then produce something new: a summary, a draft, a cleaned-up table.

Content creation runs along the same path: the user supplies the material and the assistant reorganises or writes it. Data analysis means the assistant answers questions about numbers it has been given, instead of only talking about them in general terms. Taken together — read mixed material, reason over it, produce an output — that is what separates an efficiency tool from a plain chatbot, which mostly continues a conversation.

Who it was for

Yuewen was positioned as an efficiency tool for consumer, or C-end, users^[4]. In StepFun's lineup it sat beside Maopaoya, the AI open-world platform the company also owned^[4]. The two products served different kinds of use: Maopaoya was built around role-play and open-ended interaction, while Yuewen was built around getting a task done — reading a document, making sense of a table, drafting something. That split is common among model developers, with one branch of the product serving entertainment and the other serving work.

The move to Step AI

In December 2024, StepFun stopped large-scale investment in Maopaoya, its role-play product, and merged that team into Yuewen^[5]. The combined product was later renamed Step AI^[5]. StepFun told 36Kr that the rename meant the product was shifting from a chat assistant toward agent capabilities^[5].

The distinction matters. A chat assistant answers one question at a time and waits for the next turn. An agent is expected to take a goal, break it into steps, use tools and carry the task through with less back-and-forth from the user. Folding a role-play team into an assistant and renaming it signals where the company wanted the product to go: from something you talk to, toward something that acts on your behalf. The name Yuewen therefore belongs to a particular phase — the launch period of StepFun's consumer products, when a general assistant that could read charts and text was the pitch, and before the team reoriented the product around agents.