Claude browser calling timing out / wrong ports

[fusiondev]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Dev server is running on port 3002 Claude implements some new code then it tries to access it on a different port 3000 but the dev server won’t respond and it times out.

Steps to Reproduce

it does it itself calls the browser i presume

Expected Behavior

should be either stopping the existing server or going to the correct one

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.1.34
VSCode Version: 1.105.1
Commit: 609c37304ae83141fd217c4ae638bf5321856500
Date: 2025-11-25T16:35:52.391Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 24.6.0

For AI issues: which model did you use?

Claude Opus 4.5

For AI issues: add Request ID with privacy disabled

Request ID: fe8cc9ea-0ec0-4153-a2f7-5daa30745483
{“error”:“ERROR_USER_ABORTED_REQUEST”,“details”:{“title”:“User aborted request.”,“detail”:“Tool call ended before result was received”,“isRetryable”:false,“additionalInfo”:{},“buttons”:,“planChoices”:},“isExpected”:true}

Does this stop you from using Cursor

No - Cursor works, but with this issue

[deanrie]

Hey, thanks for the report!

It looks like the Agent is making a wrong assumption about your dev server port. Since you’re already on the latest version (2.1.34), this might be a bug on our side.

A couple of quick things that might help in the meantime:

1. If you explicitly mention “the dev server is on port 3002” in your Agent prompt, does it start using the correct port?
2. What kind of dev server is this (Next.js, Vite, React, etc.)?

I’ll pass this to the team so they can check why the browser tool is defaulting to port 3000 instead of detecting your actual dev server port.