Chrome Extension: WebSocket error: [object Event]

[jonrosner]

Thank you for open sourcing this cool MCP server!

I followed the installation guide, but unfortunately the extension is unable to open a websocket connection. I get:

Chrome Extension: WebSocket error: [object Event]

Context
devtools://devtools/bundled/devtools_app.html?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@f217c2438a8e1f4b9e730de378ce20f754b2c3d0/&targetType=tab&can_dock=true

Stack Trace

devtools.js:600 (ws.onerror)

    console.error("Chrome Extension: WebSocket error:", error);

Thank you for your help!

[sarperdag]

Having the same problem... Anyone has found a solution yet?

[gerryprocee]

same problem here, it worked fine for 2 days, then starting having this issue. Anyone?

[bmacer]

I'm not sure if this is correct, but have you tested on version 1.2.0?

I can see that you're not on 1.2.0 because back in this commit a71e00d

The error message changed from:

console.error("Chrome Extension: WebSocket error:", error);

to

console.error(`Chrome Extension: WebSocket error for ${wsUrl}:`, error);

As such, it might be worth just testing 1.2.0.

[tedjames]

Thanks @bmacer ! Yes - please upgrade all three components to v1.2 and let us know if you're still having issues!

[marcegl]

The service is detected as “active,” but it does not receive the logs.

Chrome Extension: Error processing WebSocket message: TypeError: Cannot read properties of undefined (reading 'captureVisibleTab')

Context
devtools://devtools/bundled/devtools_app.html?remoteBase=https://chrome-devtools-frontend.appspot.com/serve_file/@17bb6c858e818e81744de42ed292b7060bc341e5/&targetType=tab&can_dock=true&panel=elements

      } catch (error) {
        console.error(
          "Chrome Extension: Error processing WebSocket message:",
          error
        );

[mdfu]

Note, I locally built from source, from today's Git repo version, 1.2:

I'm still having issues with the Chrome opening websocket. I'm using Edge. I tried also on Chrome. I was able to get Cursor to run the MCP Browser tool See errors below from browser-connector.js:

Browser Connector: Received request to /capture-screenshot endpoint
Browser Connector: Request body: {}
Browser Connector: Active WebSocket connection: false
Browser Connector: Starting captureScreenshot method
Browser Connector: Request headers: {
host: '127.0.0.1:3025',
connection: 'keep-alive',
accept: '/',
'accept-language': '*',
'sec-fetch-mode': 'cors',
'user-agent': 'node',
'accept-encoding': 'gzip, deflate',
'content-length': '0'
}
Browser Connector: Request method: POST
Browser Connector: No active WebSocket connection to Chrome extension