### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet - [x] This is a single bug report (please file separate reports for different bugs) - [x] I am using the latest version of Claude Code ### What's Wrong? Every time I start a new Claude Desktop session, I receive an error message: Error Couldn't start for Cowork and Code sessions. Error: Connection closed.

[BUG] MCP connection to Wolfram

Status Open

Maintainer reply None cached

Activity 1 comment · opened Sep 5, 2026

Preflight Checklist

[x] I have searched existing issues and this hasn't been reported yet
[x] This is a single bug report (please file separate reports for different bugs)
[x] I am using the latest version of Claude Code

What's Wrong?

Every time I start a new Claude Desktop session, I receive an error message: Error
Couldn't start for Cowork and Code sessions. Error: Connection closed.

The shared-pool proxy isn't handling the Wolfram MCP's stdio transport correctly for Cowork cloud sessions.
The MCP connection works fine in Chat, but fails in Cowork.

What Should Happen?

mcp-server-Wolfram.log

Error Messages/Logs

Error
Couldn't start for Cowork and Code sessions. Error: Connection closed.

Steps to Reproduce

Start Mathematica, start Claude Desktop.

Claude Model

_No response_

Is this a regression?

Yes, this worked in a previous version

Last Working Version

no idea

Claude Code Version

Claude 1.46388.4 (50e62f) 2026-09-05T01:57:47.000Z

Platform

Other

Operating System

macOS

Terminal/Shell