Hy4 preview - Tencent’s 770B open model for long-horizon work
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Hy4 Preview is a 770B MoE model (49B active, 1M context) from Tencent, built for long-horizon agentic tasks. It autonomously handles coding, game dev, and complex document analysis, running its own tests and fixing bugs before delivery.
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Flowtica Scribe
Hi everyone!
Hy4 preview is the next step after Hy3, and Tencent went much bigger this time. 770B total, 49B active, 1M context.
Tencent built a lot of the training around real work from its own engineering and specialist teams. The model is meant to stay with a task when it gets long or messy.
They also ran a blind eval with 163 internal experts across 203 engineering tasks. Hy4 preview came out slightly ahead of GLM 5.3 and Kimi K3 🤔
It is open under Apache 2.0, and you can try it now through OpenRouter or @WorkBuddy.
They are still calling it a preview. It overthinks and over-checks itself. Same habit as Hy3: put it out, see what breaks!