Claude Guard

Methodology

Claude Guard combines client-side browser collection with server-side network enrichment. The browser reports locale, timezone, fonts, WebGL, WebGPU, audio, WebRTC, permissions, UA Client Hints, and automation-related signals. The server adds the observed IP address, GeoIP fields, request language, Client Hints, and Fetch Metadata headers.

The scoring engine matches those values against SQLite rules. Weighted red and warning rules contribute to the risk score; neutral fingerprint entropy signals are shown for auditability but do not directly increase the violation score.

Limits

The result is probabilistic. A web page cannot inspect OS environment variables such as ANTHROPIC_BASE_URL, account payment data, KYC state, or Anthropic's private enforcement systems. GeoIP databases can be wrong at city or ISP level, so the verdict should be treated as a research-grade self-check.