StepFun releases 'Step 5 Preview,' a 600B MoE with a 1M-token context, on OpenRouter (community report)

What happened

According to GeekNews, StepFun's 'Step 5 Preview' has been listed on OpenRouter. It is a flagship model for agentic work such as processing large codebases and documents, tool use, and iteratively refining results over multiple steps. It uses a sparse MoE architecture that activates 27 billion of its 600 billion total parameters, with a 1-million-token context window.

Provider claims

StepFun presented Step 5 Preview as its flagship model for agentic work (community report).

Why it matters

With a Chinese model developer making a large 1M-token-context MoE immediately available via API, the range of model options for agent and coding use has widened.

Sources

• Community StepFun의 100만 토큰 컨텍스트 MoE 모델 Step 5 Preview, OpenRouter에 등장 GeekNews