MCP server fails to spawn npx (ENOENT) inside Claude Desktop — needs absolute path override

[14113]

First of all, thanks for this nice MCP server! Great work.

Description / Problem Statement
When deploying the rohlik-mcp server under Claude Desktop, it fails with the error:

spawn npx ENOENT
Server disconnected. Transport closed unexpectedly.

Even though npx, node, and npm are correctly installed and available in the user shell (which npx returns a valid path). This indicates that the Claude Desktop runtime environment’s PATH does not include the directory where npx resides.

Steps to Reproduce

1. Use default MCP server config pointing "command": "npx"
2. Run Claude Desktop (or invoke the MCP)
3. Observe spawn npx ENOENT errors in the logs
4. Change config to use absolute path to npx (e.g. /Users/adam/.local/share/mise/installs/node/22.14.0/bin/npx)
5. Restart Claude Desktop
6. MCP server initializes correctly and connects

Observed Behavior

• The system errors out with spawn npx ENOENT.
• The MCP server never properly launches via the wrapper.
• After overriding command with absolute path, the MCP server works.

Expected Behavior

• The MCP wrapper should resolve/locate npx correctly within the environment where Claude Desktop invokes it.
• Fallback or detection logic should allow using an absolute path if npx isn’t in the default PATH.

Suggested Fix / Improvements

• Inform about this in the README
• Add logic to detect npx via environment variables or a fallback search (e.g. which npx) if spawn "npx" fails.
• Allow specifying an absolute path for the command in config (already working as workaround).

Environment Details

• macOS (or environment using Claude Desktop)
• Node.js v22.14.0
• npm 10.9.2
• npx is located at /Users/adam/.local/share/mise/installs/node/22.14.0/bin/npx
• MCP config works when overriding "command" to that absolute path

Full Stack / Log Snippet

2025-10-11T08:17:57.102Z [info] [rohlik] Using MCP server command: npx with args and path: { … }
2025-10-11T08:17:57.103Z [error] [rohlik] spawn npx ENOENT
2025-10-11T08:17:57.104Z [error] [rohlik] spawn npx ENOENT
2025-10-11T08:17:57.105Z [info] [rohlik] Server transport closed
…
2025-10-11T08:18:37.323Z [error] [rohlik] spawn npx ENOENT
…
Server disconnected. For troubleshooting guidance, see debugging docs.

[tomaspavlin]

@14113 Thank you for the detailed report! I've updated README to reflect this.