mcpX product documentation
Security and privacy
Understand local transport, pairing, permissions, and sensitive browser output.
mcpX runs locally, but browser automation can still expose sensitive page data to the MCP client you selected. Treat the client as part of your trust boundary.
Data flow
Tool inputs and results move between your MCP client, the local npm server, and the Chrome extension. Snapshots, typed text, console entries, and screenshots can contain personal or sensitive information from signed-in pages.
mcpX does not add advertising, analytics, or a hosted browser-command relay. Your MCP client or model provider may process tool results under separate terms.
Local transport
The browser-control WebSocket binds to 127.0.0.1 and requires authentication.
It uses ws://, not TLS, because traffic remains on the loopback interface.
Never expose ports 3000 through 3010 with a public interface, tunnel, proxy,
or container port mapping.
Pairing credentials
Automatic pairing is available only to the official Chrome extension or an extension ID you explicitly trust. The credential is stored locally by Chrome and is not printed during normal startup.
Manual token entry is a recovery option. If you use mcpx pairing-token show,
do not paste its output into logs, screenshots, chat, or GitHub issues. Use
Forget pairing in the popup to remove the stored credential.
Chrome permissions
| Permission | Why it is needed |
|---|---|
tabs and activeTab | Identify and operate on explicit tabs. |
scripting | Inject the on-demand page agent. |
<all_urls> | Automate user-requested ordinary web pages. |
debugger | Capture explicit screenshots and console output. |
storage | Keep pairing, connection preferences, and session recovery state locally. |
mcpX rejects Chrome-internal and other restricted URL schemes.
Safer usage
- Use a separate Chrome profile for untrusted or high-risk workflows.
- Ask the client to pause before purchases, messages, deletions, or account changes.
- Avoid sending secrets through prompts or issue reports.
- Stop console monitoring when debugging is complete.
- Disconnect the extension or stop the server when browser control is not needed.
Read the full mcpX privacy policy for storage, sharing, deletion, and contact details.