Anthropic’s hidden "spyware" warning shot at China:

The issue isn’t that Anthropic can detect proxies or collect operational metadata. That is expected.

The issue is that Claude Code allegedly encoded routing and China-related fingerprints into the system prompt using near-invisible Unicode/date-format changes.

It looks mire like a indirect warning: Anthropic can fingerprint proxy-based China routing, and it wants resellers and labs to know they are being watched.