MCP servers won't initialize

[Stoxophone]

MacOS sequoia 15.3.1
Cursor v0.47.8

When adding servers to mcp.json, all servers in the MCP server list in cursor settings show an error when try to initialize: “failed to create client” or “client closed”

Heres my server list (edited to remove API keys):

And my mcp.json:

{
  "mcpServers": {
    "firecrawl-mcp-server": {
      "command": "npx",
      "args": ["-y", "firecrawl-mcp"],
      "env": {
        "FIRECRAWL_API_KEY": ...
      }
    }
  }
}

Any other MCP server I try I get the same response.

[angushhz]

I have same issue with you. Everthing set up like example
{
“mcpServers”: {
“firecrawl-mcp”: {
“command”: “npx”,
“args”: [
“-y”,
“firecrawl-mcp”
],
“env”: {
“FIRECRAWL_API_KEY”: “■■■”
}
}
}
}

Version: 0.47.8
VSCode Version: 1.96.2
Node.js: 20.18.1
V8: 12.8.374.38-electron.0
OS: Darwin arm64 24.1.0

@ SSE error: TypeError: fetch failed: connect ECONNREFUSED 127.0.0.1:3000, connect ECONNREFUSED ::1:300C

[deanrie]

Hey, it’s working as expected for me. Also, make sure you have Node.js installed on your system.

[Stoxophone]

Is this cursor v0.47.8?

Actually you make a good point about Node.js. I’m using devbox for this project so all of my dependancies are handled through it, including node. Switching to devbox run npx as the command remedies the issue of no node installed, but the mcp server is still not able to initialize.

[angushhz]

Absolutely. It’s so weird. I have using debug tool of MCP

Debugging - Model Context Protocol

I can init it local when using this tool. I am try multiple node version > 18 → 22. But i can’t start any MCP tools in cursor setting. idk
Im run in mac os 15.3.2 apple m1

╰─ nvm list
v10.16.0
→ v14.18.0
v16.20.0
v18.20.4
v20.18.2
v22.13.1
system
default → 14 (-> v14.18.0)
use → 14 (-> v14.18.0)
iojs → N/A (default)
unstable → N/A (default)
node → stable (-> v22.13.1) (default)
stable → 22.13 (-> v22.13.1) (default)
I have a question about your setting mcp server. If i setup it is not global setting mcp Which node version cursor will using for execute mcp ?

[deanrie]

Hey, my version is 0.47.8. Maybe it doesn’t work with devbox. In this case, try configuring MCP for the project instead of using a global setup.

[angushhz]

Thank you for your reply.
It make me doubt about version default of node in my enviroment.
My default dev version in nvm is always 14.6 . Therefore i have change default to > 20. Now MCP Servers work correctly .