Simon Willison Flags Tencent's Hy3 — a 295B Apache-2.0 Open MoE That Rivals GLM-5.2 and DeepSeek-V4, Free on OpenRouter Until July 21

simonwillison.net·high signal

On July 6-7 Simon Willison covered Tencent's newly open-sourced Hy3, a 295B-parameter Mixture-of-Experts model (21B active, 256K context) released under Apache 2.0 and free on OpenRouter through July 21. By Tencent's numbers hallucinations dropped from 12.5% to 5.4% and it beats GPT-5.5 on scientific tasks while rivaling flagship open models 2-5x its size. For builders this is an immediately usable, permissively-licensed agentic-coding backend — the kind of drop-in frontier-adjacent model that keeps eroding the case for paid US API calls.