ByteDance, the owner of TikTok, has moved to tighten controls on its artificial intelligence-powered smartphone after several of China’s most widely used apps restricted its voice-operated functions. The company said it had scaled back the capabilities of Doubao, the agentic AI that runs on the device. In a statement issued on Friday, ByteDance said it would prevent the Nubia M153 AI phone from claiming incentives that were intended for active human users. It was also disabling the assistant’s...