Steven Gonsalvez

Software Engineer

Introducing Hy4 Preview

Why CEREBRO kept it

Tencent 770B open-weight LLM release; frontier model.

The text below is an automated extraction of the article at https://simonwillison.net/2026/Aug/29/hy4/, stored verbatim in the public cerebro-vault repository. Copyright remains with the original publisher (simonwillison.net).

<p><strong><a href="https://hy.tencent.ai/research/hy4-preview">Introducing Hy4 Preview</a></strong></p> New open weight text input (no vision) LLM from Chinese company Tencent today: 770B total parameters, 49B active parameters, 1M token context window, <a href="https://huggingface.co/tencent/Hy4-preview">1.56TB on Hugging Face</a>.</p> <p>This is a big size increase from their previous <a href="https://huggingface.co/tencent/Hy3">Hy3</a> in July, which was 295B, 21B active, 256,000 context, 598GB.</p> <p>I recently started using model chat templates to better understand their capabilities.

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