Fuck Claude

According to public reverse-engineering reports, when Claude Code talks to a non-official endpoint it reads the OS timezone and proxy hostname, and steganographically encodes the result into its system prompt. The timezone this page reads via Intl.DateTimeFormat is the very same OS timezone.

No. Only the system timezone maps one-to-one onto Claude's reported mechanism. The other signals are common Chinese-environment fingerprints that correlate with it, so treat the score as an estimate, not a verdict.

Switch your OS timezone away from China zones such as Asia/Shanghai, move zh-CN off the top of your browser language list, and avoid routing Claude Code through proxies whose hostnames contain flagged domains or AI-lab keywords.

The tool checks 11 browser fingerprint signals: system timezone (weight 26, same as Claude), browser language (20), installed Chinese fonts (17), Intl locale (8), timezone offset (6), emoji rendering style (5), WebGL renderer (5), screen resolution (4), network info (3), browser plugins (3), and privacy signals like DNT/GPC (3).

When Claude Code detects a China user via timezone or proxy hostname, it reportedly encodes this verdict into the system prompt using visually identical Unicode characters — swapping the date separator dash with a slash, and rotating among four look-alike apostrophe variants to encode additional flags.

No. Every check runs 100% locally in your browser. None of the detected signals are ever sent anywhere.