Three days after ByteDance launched its AI agent phone, WeChat shut it down. The "Doubao Assistant" can no longer log into WeChat or execute any WeChat-related commands.

This mirrors Amazon blocking Perplexity's Comet browser. The pattern is clear: AI agent competition in China will be an ecosystem war.

ByteDance can't access WeChat's 1.3 billion users. When Tencent launches its own agent, expect it to be blocked from Douyin and Taobao. Alibaba's agent won't touch WeChat or Douyin.

Each company will build powerful agents, but only within their own walls. The platform moat becomes the agent's boundary.

The original promise: AI agents that work across any platform. The reality: fragmented ecosystems that mirror existing platform competition.

Users will need multiple agents to live their digital lives. The friction just moved up one layer.