StepFun is playing the same open-weights card that made DeepSeek and Qwen global reference points, and a 27B-active MoE with 1M context is a serious spec sheet for agentic workloads. The catch is that 'Preview' means no proven benchmark track record yet — parameter counts and context windows are cheap to advertise, quality is not. Still, every credible open release in this weight class narrows the gap with closed frontier models and hands developers another cheap long-context option. On our view, the real test will be independent evals on tool use and multi-step tasks, not the launch post. Worth watching closely.