A Mixture-of-Experts design featuring 27 billion active parameters powers the latest flagship AI for agentic software engineering and finance. StepFun's Step 5 Preview utilizes a total of 600 billion parameters and a 1 million token context window to maintain execution over long horizons in professional knowledge work.

The developer releases the model weights on October 15. The system integrates vision capabilities and targets lower task costs than existing frontier models while maintaining comparable intelligence for software development tasks.