spawn npx ENOENT in MCP: How to Fix It (Claude Desktop, Cursor, Claude Code)

spawn npx ENOENT means the MCP client tried to start your server with the npx command and the operating system could not find a program by that name. Nothing is wrong with the server itself yet. The fastest fix is to find the real location of npx (run which npx on macOS or Linux, where npx on Windows), put that full path in the command field, and restart the client.

Checked against: the Node.js child_process docs, the MCP local server guide, the MCP debugging guide and the source of the @modelcontextprotocol/sdk 1.32.2 npm package on 2 November 2026. eSEOspace did not reproduce the error on every OS.

What this error means

Most desktop MCP clients are built on Node.js. They launch a local server with a child process call. The Node.js docs say that if the working directory does not exist, the child "emits an ENOENT error and exits immediately," and that "ENOENT is also emitted when the command does not exist."

So spawn npx ENOENT reads as: "I tried to spawn npx and it was not there." The program is missing from the search path the client uses, or Node is not installed at all.

Why does it work in your terminal? The MCP debugging guide says stdio servers "inherit only a limited subset of environment variables automatically." The TypeScript SDK's stdio client, checked in version 1.32.2, passes only HOME, LOGNAME, PATH, SHELL, TERM and USER on macOS and Linux by default. If the client app itself was opened from the Dock or Start menu, its PATH never included the folders your shell profile adds.

A GitHub thread about nvm shows the same pattern. An MCP maintainer explained that nvm works through "a very complicated shell function" in your profile, which GUI apps do not load.

Quick fix

1. Confirm Node is installed: run node --version and npx --version in a terminal. If either fails, install the Node.js LTS release from nodejs.org, as the local server guide recommends.
2. Find the full path: which npx (macOS, Linux) or where npx (Windows).
3. Replace "command": "npx" with that path.
4. Because npx itself calls node, add the same folder to PATH in the env block.
5. Fully quit and reopen the client.

Example for macOS with Node from nvm (your version folder will differ):

{
  "mcpServers": {
    "filesystem": {
      "command": "/Users/you/.nvm/versions/node/v24.11.0/bin/npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "/Users/you/Desktop"],
      "env": {
        "PATH": "/Users/you/.nvm/versions/node/v24.11.0/bin:/usr/bin:/bin"
      }
    }
  }
}

The nvm thread's other workaround also works: install the server globally with npm, then call node by full path with the full path to the server's script.

Fix by client / OS

Claude Desktop

Edit claude_desktop_config.json through Settings > Developer > Edit Config, then quit with Cmd+Q (macOS) or from the tray icon (Windows). On Windows, if the log mentions ${APPDATA}, the local server guide says to add the expanded APPDATA value to env and to make sure npm is installed globally, which you can check by looking for %APPDATA%\npm. If you install the server as a desktop extension instead, Claude's help article says Claude Desktop has a built-in Node.js, so no system Node is needed for extensions.

Cursor

Edit ~/.cursor/mcp.json or the project's .cursor/mcp.json. Cursor's MCP docs say Cursor resolves ${userHome} and ${env:NAME} inside command, args and env, which helps keep a shared file portable. Open Output and pick MCP Logs to see the spawn error.

Claude Code

Claude Code runs from your terminal, so it usually inherits your shell's PATH. If you still see ENOENT, add the server with a full path after the -- separator, as the Claude Code MCP docs show: claude mcp add myserver -- /full/path/to/npx -y package-name.

Windows in any client

npx on Windows is npx.cmd. The Node.js docs say .bat and .cmd files can be run by "spawning cmd.exe and passing the .bat or .cmd file as an argument." The TypeScript SDK client uses the cross-spawn package, which handles this for you. If a client does not, wrap the call:

{
  "mcpServers": {
    "filesystem": {
      "command": "cmd",
      "args": ["/c", "npx", "-y", "@modelcontextprotocol/server-filesystem", "C:\\Users\\you\\Desktop"]
    }
  }
}

More Windows causes are in MCP server failed to start on Windows.

Where to find the logs

• Claude Desktop: mcp.log in ~/Library/Logs/Claude (macOS), %APPDATA%\Claude\logs (Windows) or ~/.config/Claude/logs (Linux), per the debugging guide.
• Cursor: Output panel, MCP Logs.
• Claude Code: claude mcp list shows ✘ Failed to connect with the error detail, and claude mcp get <name> shows it on an Issue: line.

If it still fails

• ENOENT with a full path means the path is wrong or the folder in cwd does not exist. Copy the path again from which or where.
• The server starts, then exits. That is a new error. Read mcp-server-SERVERNAME.log, and see could not attach to MCP server.
• The package needs a newer Node. See MCP Node version errors.
• Python servers fail the same way with spawn uvx ENOENT. See uvx not found.

Look up any JSON-RPC code that appears next in the MCP error code lookup. Teams that want one tested config for every laptop can get help through MCP development.

Frequently asked questions