Tencent's Hunyuan open-source 4B parameter mobile agent model, PhoneBuddy.

Tencent Hunyuan open-sourced the PhoneBuddy 4B mobile agent model, simultaneously releasing five papers including PhoneWorld and PhoneHarness, covering the entire chain of environment, training, execution, privacy, and security. The model's core innovation employs a hybrid Real+Mock RL training approach, combining real apps with a self-built PhoneWorld mock environment, enabling the 4B model to outperform GPT-5.4 in multiple metrics across 150 real-device evaluations.