"Not connected" error

[KikeVen]

On Windows 11:

I was unable to successfully set up the Sequential Thinking MCP server. I encountered a "Not connected" error despite trying various configuration changes and troubleshooting steps. I suspect there might be a deeper issue with the MCP server setup or the extension's handling of MCP servers that I'm unable to resolve with the available tools and information.

When I run:

npx -y @modelcontextprotocol/server-sequential-thinking

I get : Sequential Thinking MCP Server running on stdio

if cline runs it:
Error Error executing MCP tool: Not connected

[Vladykart]

Based on the logs you've provided, I'll draft a comprehensive issue message for GitHub:

Issue: Sequential Thinking MCP Server Dependency Error in Claude Desktop

Problem Description

The Sequential Thinking MCP server fails to initialize due to a missing dependency. While the server begins to start and successfully connects, it crashes when trying to import the MCP SDK.

Environment

• OS: macOS
• Node.js: v20.11.0
• Claude Desktop (latest version)
• MCP Server: Sequential Thinking

Error Details

The server consistently fails with this error:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/Users/vlad/.npm/_npx/de2bd410102f5eda/node_modules/@modelcontextprotocol/sdk/dist/server/index.js' imported from /Users/vlad/.npm/_npx/de2bd410102f5eda/node_modules/@modelcontextprotocol/server-sequential-thinking/dist/index.js

Reproduction Steps

1. Added Sequential Thinking MCP server to claude_desktop_config.json
2. Started Claude Desktop which attempts to initialize the server
3. Server starts and connects but immediately crashes with the module not found error
4. Multiple restart attempts show the same behavior

Logs

I've attached the logs showing multiple failed initialization attempts. The pattern is consistent:

1. Server initializes
2. Connection is established
3. Server crashes with ERR_MODULE_NOT_FOUND for the SDK module
4. Connection is terminated

Attempted Solutions

I've tried:

• Different installation methods (npx, github reference)
• Updating the configuration file
• Using different versions of the server
• Installing dependencies manually

This appears to be a dependency resolution issue where the Sequential Thinking server is looking for a specific version of the SDK (@modelcontextprotocol/sdk/dist/server/index.js) but cannot find it in the expected location.

Thank you!

mcp-server-sequential-thinking.log

[jeanchristophe13v]

same issue

[atemerev]

Same problem, examples do not work with Claude Desktop

[zhaoyim]

the cline auto added conf is :

"github.com/modelcontextprotocol/servers/blob/main/src/sequentialthinking": {
"command": "npx",
"args": [
"-y",
"@modelcontextprotocol/server-sequentialthinking"
],
"disabled": false,
"autoApprove": []
}

you should change "@modelcontextprotocol/server-sequentialthinking" to "@modelcontextprotocol/server-sequential-thinking"

[bobtista]

This works for me for now as a workaround, just use an older version. For the server-filesystem for example, use:
"@modelcontextprotocol/[email protected]"

[sevonade4]

I work around this by git cloning the servers and then go inside the sequentialthinking folder and ran npm install and npm run build.

and now the json looks like this:
"sequential-thinking": {
"command": "node",
"args": [
"C:\Users\mypc\Documents\dev\mcp_servers\servers\src\sequentialthinking\dist\index.js"
]
}

[Chmavo]

On Windows 11:

I was unable to successfully set up the Sequential Thinking MCP server. I encountered a "Not connected" error despite trying various configuration changes and troubleshooting steps. I suspect there might be a deeper issue with the MCP server setup or the extension's handling of MCP servers that I'm unable to resolve with the available tools and information.

When I run:

npx -y @modelcontextprotocol/server-sequential-thinking

I get : Sequential Thinking MCP Server running on stdio

if cline runs it: Error Error executing MCP tool: Not connected

Same issue on MacOS

[dysangel]

this mcp server is working in Cursor on one of my machines, but the other one just says "client closed"