Remote MCP Server On Cloudflare D9g

🚀 Building a Remote MCP Server on Cloudflare

Let's build a running remote MCP server on Cloudflare Workers and integrate OAuth login!

🚀 Quick Start

💻 Local Development

# Clone the repository
git clone git@github.com:cloudflare/ai.git

# Install dependencies
cd ai
npm install

# Run locally
npx nx dev remote-mcp-server

You should be able to open a browser window at http://localhost:8787/.

🔗 Connecting the MCP Inspector to Your Server

To explore the new MCP API, you can use the MCP Inspector.

• Start it using npx @modelcontextprotocol/inspector.
• In the inspector, switch the transport type to SSE, enter http://localhost:8787/sse in the URL to connect to the MCP server, and then click "Connect".
• You will be redirected to a (simulated) user/password login screen. Enter any email and password to log in.
• You should be redirected back to the MCP inspector, and you can now list and call any defined tools!

🔗 Connecting Claude Desktop to the Local MCP Server

The MCP inspector is great, but we really want to connect it to Claude! Follow Anthropic's Quick Start Guide, go to "Settings" > "Developer" > "Edit Configuration" in Claude Desktop, and find your configuration file. Open the file in a text editor and replace it with the following configuration:

{
  "mcpServers": {
    "math": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "http://localhost:8787/sse"
      ]
    }
  }
}

This will run a local proxy that allows Claude to communicate with your MCP server over HTTP. When you open Claude, a browser window should open and allow you to log in. You should see the available tools in the bottom right corner. As prompted, Claude should call the MCP addition tool to answer questions.

🚀 Deployment to Cloudflare

1. npx wrangler kv namespace create OAUTH_KV
2. Follow the guide to add the KV namespace ID to wrangler.jsonc
3. npm run deploy

🔗 Calling Your Newly Deployed Remote MCP Server from a Remote MCP Client

Just as you did in "Local Development", run the MCP inspector: npx @modelcontextprotocol/inspector@latest Then enter your Worker's workers.dev URL (e.g., worker-name.account-name.workers.dev/sse) as the MCP server URL in the inspector and click "Connect". You are now connected to your MCP server via a remote MCP client.

🔗 Connecting Claude Desktop to Your Remote MCP Server

Update the Claude configuration file to point to your workers.dev URL (e.g., worker-name.account-name.workers.dev/sse), and then restart Claude.

{
  "mcpServers": {
    "math": {
      "command": "npx",
      "args": [
        "mcp-remote",
        "https://worker-name.account-name.workers.dev/sse"
      ]
    }
  }
}

🐞 Debugging

If you encounter issues, restarting Claude or directly connecting to your MCP server via the following command may be helpful.

npx mcp-remote http://localhost:8787/sse

In rare cases, clearing the files in the ~/.mcp-auth directory may be helpful.

rm -rf ~/.mcp-auth