Lion MCP Server

🚀 Set Up a Remote MCP Server on Cloudflare

Let's launch a remote MCP server on Cloudflare Workers and integrate OAuth login functionality!

🚀 Quick Start

📦 Installation

# 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 http://localhost:8787/ in your browser to view the server.

💻 Usage Examples

Connect 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 and enter http://localhost:8787/sse as the URL of the MCP server to connect, then click "Connect".
• You'll be redirected to a (simulated) user/password login page. Enter any email and password to log in.
• You should be redirected back to the MCP inspector, and now you can list and call any defined tools!

Connect Claude Desktop to Your Local MCP Server

The MCP inspector is great, but what we really want to do is connect it to Claude! Follow the Anthropic's Quick Start Guide, go to Settings > Developer > Edit Configuration in Claude Desktop to find your configuration file.

Open the file with a text editor and replace it with the following content:

{
  "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 via 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 be able to call the tools.

🚀 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

Connect to Your Newly Deployed Remote MCP Server from a Remote MCP Client

Just as you did in "Local Development" above, run the MCP inspector: npx @modelcontextprotocol/inspector@latest

Then, in the inspector, enter your Worker's workers.dev URL (e.g., worker-name.account-name.workers.dev/sse) as the URL of the MCP server to connect, and click "Connect".

You are now connected to your MCP server via the remote MCP client.

Connect 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 help.

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

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

rm -rf ~/.mcp-auth