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MCP server disconnects / URL returns Unauthorized #4
Description
I followed the tutorial video from this article but I think I may have missed something.
https://blog.cloudflare.com/model-context-protocol/
My index.ts looks like this:
import { WorkerEntrypoint } from 'cloudflare:workers';
import { ProxyToSelf } from 'workers-mcp';
export default class MyWorker extends WorkerEntrypoint<Env> {
/**
* A warm, friendly greeting from your new Workers MCP server.
* @param name {string} the name of the person we are greeting.
* @return {string} the contents of our greeting.
*/
sayHello(name: string) {
return `Hello from an MCP Worker, ${name}!`;
}
/**
* @ignore
**/
async fetch(request: Request): Promise<Response> {
return new ProxyToSelf(this).fetch(request);
}
}And my claude_desktop_config.json looks like this:
{
"mcpServers": {
"image-gen-mcp": {
"command": "/Users/my_user_name/Developer/my-mcp/node_modules/.bin/workers-mcp",
"args": [
"run",
"my-mcp",
"https://my-mcp.my-subdomain.workers.dev",
"/Users/my_user_name/Developer/my-mcp"
],
"env": {}
}
}
}When I start Claude I get an error saying the MCP server disconnected. When I try to visit the URL for the MCP on my subdomain it just says "Unauthorized".
I was wondering if this was possibly related to the SHARED_SECRET that gets created? I tried adding it to the env section of Claude's MCP config but that didn't seem to fix it.
Activity
robdodson commentedon Jan 4, 2025
Looking in Claude's log file for my MCP server (found at
~/Library/Logs/Claude), it looks like there might be something wrong with the build:robdodson commentedon Jan 5, 2025
It looks like Claude was creating a non-interactive shell which doesn't load .zshrc, so nvm was not being initialized correctly. Claude was using an older version of node from nvm, v16, which doesn't have scheduler in node:timers/promises. I "fixed" the issue by just deleting node 16, which leaves only node 20 in my list of nvm versions.