Pandaily2 min read
StepFun Step 5 Preview: ~600B MoE Long-Horizon Agent; Open Weights Due Oct 15
StepFun launched Step 5 Preview on September 20, 2026: a ~600B sparse MoE (~27B active) with 1M context for long-horizon agents, API live now and BF16 open weights planned for October 15.
By PandailyPandaily
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Originally published by Pandaily on Sep 28, 2026.
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