An anonymous reader quotes a report from Ars Technica: Anthropic quickly removed a tracker secretly monitoring Claude Code users in China after a security researcher exposed the hidden code and condemned the spyware-like tracking as a "serious breach of user trust." Last week, a web developer known as "Thereallo" was researching privacy issues in Claude Code and was shocked to find that the AI firm was using "prompt steganography" to hide code that tracks Chinese users "in plain sight." This code wasn't malicious, but it was sending information to Anthropic that most users wouldn't detect, relying on shorthand markers to quietly flag users' timezone, proxy, and potential connection to Chines...