[BUG] MCP server '...' is a local/stdio server. Plugins may only declare remote (http/sse/ws) or MCPB servers.

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?

On Cowork, I cannot install a plugin that has a local/stdio MCP server anymore.

Here's the error message:

<img width="547" height="401" alt="Image" src="https://github.com/user-attachments/assets/f6d74e53-0357-4acb-8d51-fa749d2240b5" />

It didn't happen 2 days ago.

What Should Happen?

It should allow me to install a plugin with a local/stdio server.

Also, there should be a documentation about how to integrate MCPB server with a plugin

Error Messages/Logs

Steps to Reproduce

1. Install a plugin with a local/stdio MCP server
2. Encounter the error message

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude for Mac (Cowork) Version 1.14271.0 (c8f4d8)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_