It drives the browser you are already signed into, so your sessions, cookies, and extensions come along. Nothing is launched headless and nothing leaves the machine.

Tools

browser_snapshot · browser_navigate · browser_click · browser_type · browser_press · browser_scroll · browser_screenshot · browser_extract · browser_solve_captcha · weboperator_execute_goal

browser_snapshot returns an accessibility tree with numbered interactive elements; the action tools take those numbers, so an agent never guesses at CSS selectors.

Install

The server talks to Chrome through the WebOperator extension and a Native Messaging host, so install the extension first, then register the host:

npx -p weboperator-mcp weboperator-bridge-install

Then point your client at the server:

{
  "mcpServers": {
    "weboperator": {
      "command": "npx",
      "args": ["-y", "weboperator-mcp"]
    }
  }
}

Reload the extension in chrome://extensions after registering the host.

Configuration

Variable	Default	What it does
`WEBOPERATOR_BRIDGE_PORT`	`8765`	Port of the local bridge HTTP API
`WEBOPERATOR_BRIDGE_HOST`	`127.0.0.1`	Bridge bind address
`WEBOPERATOR_AGENT_SOCKET`	`/tmp/weboperator-bridge.sock`	Unix socket the bridge listens on
`WEBOPERATOR_API_TOKEN`	(unset)	Shared token, required when unauthenticated bridge access is disabled

macOS and Linux. Chrome, Chromium, Brave, Edge, and Arc are all registered by the installer.

Security

Page content is treated as data, never as instructions — the extension's prompt-injection fixtures live in evals/fixtures/. browser_solve_captcha pauses for you rather than defeating a challenge, and login flows stop for a human instead of typing credentials.