Tencent has released Hy4 Preview, a new open weight text-only large language model with 770 billion total parameters and a one million token context window. The model weighs 1.56TB and is available on Hugging Face, representing a significant increase in size compared to the previous Hy3 release. Analysis of the chat template reveals a binary reasoning effort setting, defaulting to high logic or disabling thought entirely. Testing the model with a prompt to generate an SVG of a pelican riding a bicycle produced a flat vector illustration against a pale blue sky. The internal reasoning trace displayed slightly truncated English as it considered adding a helmet or sunglasses before deciding against them to avoid obscuring the bird’s large beak.
This release demonstrates how massive parameter counts and extended context windows coexist with simplified reasoning interfaces. The model prioritises visual accuracy in generated code while maintaining a distinct internal monologue that balances creativity with constraint. Key specifications include:
- 770B total parameters
- 1M token context window
- Binary reasoning modes
