Claude China Environment Check

Claude China Environment Check is a browser-based tool that estimates how strongly your current setup resembles a typical China-region user profile. Public reverse-engineering reports suggest Claude Code may read the OS timezone and proxy hostname when using non-official endpoints, then encode the verdict inside its system prompt. This checker cannot replicate Claude's internal pipeline exactly, but it reads the same OS timezone and adds eight more browser-visible fingerprints—language, Chinese fonts, vendor fonts, Chinese browsers, device brand, Intl locale, UTC+8 offset, and emoji style—to produce a weighted 0–100 score.

Everything runs locally in your browser. Scan results are never uploaded, making it useful before changing proxies, locale settings, or troubleshooting Claude Code access issues.

What gets scanned

• System timezone — the same OS timezone Claude Code is reported to read
• Browser language — whether zh-CN or Simplified Chinese ranks first
• Installed Chinese fonts — Microsoft YaHei, PingFang SC, and similar faces
• Chinese vendor fonts — MiSans, HarmonyOS Sans, OPPO Sans, and more
• Chinese browser / WebView — WeChat, QQ, Quark, UC, Baidu, etc.
• Chinese-brand device — HarmonyOS, Huawei, Xiaomi, OPPO, vivo hints
• Intl locale — locale used for date and number formatting
• Timezone offset — whether the offset matches UTC+8
• Emoji rendering style — a weak auxiliary signal

How to use

1. Open the tool page and wait for the embedded checker to load
2. Click Start scan to run the local analysis
3. Review the 0–100 score and Low / Medium / High bands
4. Use Open in new tab for the standalone full-page experience

FAQ

Is this Claude's exact internal check?
No. Only the system timezone maps one-to-one; other signals are common China-environment fingerprints and should be treated as estimates.

How can I lower the score?
Move your OS timezone away from China zones, deprioritize zh-CN in browser languages, and avoid proxies whose hostnames contain flagged patterns.

Is any data uploaded?
No. All checks run locally; detected signals are never sent anywhere.