Tencent spotted testing Hy4 model in Yuanbao app as expert-level model

Tencent has unveiled Hy4 Preview, an open-source Mixture-of-Experts (MoE) model. The release marks a significant escalation in China’s intensifying AI arms race, where the country’s biggest tech companies are racing to build ever-larger foundation models. For context, Tencent’s previous Hy3 model clocked in at 295 billion total parameters. Think of parameters as the knobs and dials that a model can tune during training: more parameters generally means a model can learn more nuanced patterns, though how efficiently those parameters are used matters just as much. From Hy3 to Hy4: a rapid evolution The Hy4 Preview builds on what was already a strong foundation. Tencent’s Hy3 model, a 295B total parameter MoE architecture with 21B active parameters and a 256K context window, was open-sourced under the Apache 2.0 license in April 2026 before receiving its formal release in July. Weekly usage of Hy3 rose more than 68-fold after it transitioned from preview to formal release. Hy3 became the engine behind a growing suite of Tencent products, powering features across Yuanbao (Tencent’s AI assistant app), CodeBuddy (its coding assistant), and WorkBuddy (its enterprise productivity tool). The...