Cline said Tencent Hy4 Preview currently leads SWE-bench Pro. The open-weight model is described as 770B parameters with 49B active and a 1M-token context window, and Cline called it Tencent's biggest generational leap measured to date. The practical developer path is immediate: npm i -g cline, run /model, and select Hy4 preview. SWE-bench Pro is a harder, more realistic software-engineering eval than classic HumanEval-style completion, so a lead there is a stronger signal for repository-level agents than a short coding quiz. The 1M context window is the other half of the story: long-horizon refactors, multi-file patches, and eval traces can stay in a single session instead of being retrieved in fragments. Cline's distribution also matters; putting Hy4 beside GLM-5.3 and Qwen3.8 in the same agent makes model shopping a /model command rather than a new IDE.
Key Takeaways
- โHy4 Preview is an open-weight 770B/49B-active model with 1M context that Cline says leads SWE-bench Pro.
- โCline calls it Tencent's largest measured generational leap and already hosts Hy4 preview in-product.
- โDevelopers can switch via npm i -g cline and /model for repository-scale long-context repairs.