StepFun launches Step 3.5 Flash 2603
StepFun has rolled out Step 3.5 Flash 2603, an updated version of its Step 3.5 Flash model for Step Plan users. The release adds a low-think mode and targets coding and agent frameworks, with StepFun claiming similar reasoning quality in high mode while reducing token use by about 14%, and up to 56% in low-think mode. The update is clearly aimed at high-frequency, lower-complexity agent tasks where speed and cost matter more than exhaustive reasoning.
This looks like a practical efficiency upgrade rather than a brand-new model reset.
- –Low-think mode is the main feature: it gives users a cheaper, faster option for routine agent steps.
- –The coding and agent tuning suggests StepFun is optimizing for real workflows, not just benchmark vanity.
- –If the token-savings hold in practice, this becomes a strong fit for orchestration layers and multi-model stacks.
- –The launch matters most to existing Step Plan users and OpenClaw/OpenRouter adopters who run lots of short, repetitive tasks.
DISCOVERED
55d ago
2026-04-02
PUBLISHED
55d ago
2026-04-02
RELEVANCE
AUTHOR
tarruda