Browser Helper: Site Metadata & Domain Exit Probes
Standard web pages cannot read cross-origin Claude cookies or trace responses. Installing this optional helper allows inspecting cookie names/flags and fixed-domain trace exits without reading credential values.
An embedded webview, a different browser profile, or another computer will not reflect your Claude browser state. Version 5.0 supports both localhost and claudetest.app.
Download Browser Helper (ZIP)- Download the ZIP above, extract all files to a local folder, and note the folder location.
- Open the Chrome Extensions page (
chrome://extensions) or the Edge Extensions page (edge://extensions）。 - Enable "Developer mode", click "Load unpacked", and select the extracted folder containing
manifest.json. - Click the helper icon in your browser toolbar, then click "Authorize Claude Site Metadata Check" (or Domain Probe). You can revoke permissions or uninstall at any time.
- Open the Online Site (claudetest.app) or the Local Server (127.0.0.1:4173) in the same browser profile, refresh the page, and click "Run Full Check".
If a Claude tab is currently open, the helper also inspects top-level localStorage/sessionStorage key names; if no tab is open, it still checks visible cookie metadata without opening or reloading Claude.
Domain Exit Probe Permission
Helper v5 adds a separate "Authorize Domain Exit Probe" permission. It sends anonymous requests to fixed /cdn-cgi/trace endpoints without cookies or credentials to supplement browser CORS-restricted probes.
What the Helper Reads
| Item | How It Is Handled |
|---|---|
| Cookie | Retains only cookie name, domain, and HttpOnly/Secure/Session flags. Although the Chrome cookies API includes values, our sanitizer immediately discards the value field and never passes it to the page. |
| Open Tab Storage Keys | Key names only (via Storage.key()); never calls getItem() and never reads storage values or chat DOM content. |
| Domain Scope | Strictly limited to claude.ai, claude.com (and subdomains), and console.anthropic.com; look-alike domains are rejected. |
| Storage & Export | Metadata is passed only to localhost or claudetest.app in memory and is never written to history or uploaded. Optional ProxyCheck lookups send only the target public IP via the same-origin relay (cached up to 10 minutes). |
How Matches Are Interpreted
Key names are normalized and matched against known aliases, semantic tokens, and conservative Levenshtein similarity. Similarity reflects string closeness, not ban risk.
Matched cookie names indicate possible site traces in this profile but cannot verify whether a session is active or restricted; zero matches do not prove you never signed in.
Languages & Local OS Settings
Online mode checks browser languages; running the local server on Windows additionally checks Windows format culture, UI language, system locale, home region, proxy/TUN status, and matched software names without reading file paths or credentials.
OS and software names are processed locally and never stored in history. Normal websites cannot enumerate your installed software.
Chinese locale and region differences are noted as weak environmental signals; there is no official evidence that Chinese language settings alone cause account bans.
How Matching Rules Are Updated
View Current JSON Rules ↗. Maintainers can update language prefixes, marker aliases/tokens, software aliases, and matching thresholds in context-v3.json without changing application code.
When a check cannot complete, the exact reason is shown. Opaque new key names remain categorized as unrecognized until added to the rule catalog.
References & Verification Date
2026-10-15。Anthropic Privacy Policy describes collection of device, connection, and cookie data; internal risk rules are not publicly disclosed. MDN Navigator.languages、Same-Origin Policy、Chrome cookies API、Windows International PowerShell Docs。
Independent diagnostic suite · Unaffiliated with Anthropic · No ban probability scores · Local vs. Online capabilities clearly labeled