Cloudflare MCP Lab

# Model Context Protocol (MCP) Server + Google OAuth This is a [Model Context Protocol (MCP)](https://modelcontextprotocol.io/introduction) server that supports remote MCP connections, with Google OAuth built-in. You can deploy it to your own Cloudflare account, and after you create your own Google Cloud OAuth client app, you'll have a fully functional remote MCP server that you can build off. Users will be able to connect to your MCP server by signing in with their Google account. You can use this as a reference example for how to integrate other OAuth providers with an MCP server deployed to Cloudflare, using the [`workers-oauth-provider` library](https://github.com/cloudflare/workers-oauth-provider). The MCP server (powered by [Cloudflare Workers](https://developers.cloudflare.com/workers/)): ## Getting Started ### Prerequisites Install wrangler (globally): ```bash npm i -g wrangler@latest ``` ### Google Cloud Console Settings Create an OAuth app with client ID and client secret: - Add `http://localhost:8788/callback` as the redirect URL ### Cloudflare Settings #### Create KV Cache Database Create a KV cache DB and note down its ID. Add the following keys: - `GOOGLE_CLIENT_ID` - `GOOGLE_CLIENT_SECRET` - `COOKIE_ENCRYPTION_KEY` You can use openssl to generate a 32-byte random value as COOKIE_ENCRYPTION_KEY: ```bash openssl rand -hex 32 ``` #### Create D1 Database Create a D1 database with name `sql_employees` and note down its ID. Import data using `simple_import_employees.sql`: ```bash wrangler d1 execute employees --remote --file ./simple_import_employees.sql ``` --- ### To Make the Current Repo Work **Step 1:** Install dependencies ```bash npm install ``` **Step 2:** Modify `wrangler.jsonc` - Replace `<ADD-KV-ID>` with your KV ID - Replace `<ADD-D1-ID>` with your D1 ID **Step 3:** Prepare KV in your local space ```bash wrangler kv key put --local "GOOGLE_CLIENT_ID" "<your-google-client-id>" --binding="OAUTH_KV" wrangler kv key put --local "GOOGLE_CLIENT_SECRET" "<your-google-client-secret>" --binding="OAUTH_KV" wrangler kv key put --local "COOKIE_ENCRYPTION_KEY" "<your-cookie-encryption-key>" --binding="OAUTH_KV" ``` **Step 4:** Run locally ```bash npm run dev # or wrangler dev ``` The local MCP server should be up on port 8788. You can test it now on Postman. **Step 5:** Deploy to production ```bash npm run deploy # or wrangler deploy ``` After a while you should see it at the Cloudflare platform. Note down its URL: `<remote-mcp-url>` **Step 6:** Update Google Cloud Console Go to your Google Cloud Console again and add the following to the redirect URL list: - `https://<remote-mcp-url>/callback` Now you should be able to use the remote MCP server as well! ### To Follow My Video and Start Everything From Scratch You can start building it with command: ```bash npm create cloudflare@latest -- my-mcp-server --template=cloudflare/ai/demos/remote-mcp-google-oauth ``` Note: This is slow and takes some time. --- ### Access the Remote MCP Server from Claude Desktop Open Claude Desktop and navigate to Settings -> Developer -> Edit Config. This opens the configuration file that controls which MCP servers Claude can access. Replace the content with the following configuration. Once you restart Claude Desktop, a browser window will open showing your OAuth login page. Complete the authentication flow to grant Claude access to your MCP server. After you grant access, the tools will become available for you to use. ```json { "mcpServers": { "employee-db": { "command": "npx", "args": [ "mcp-remote", "https://<your-remote-mcp-url>/mcp" ] } } } ``` Once the Tools (under 🔨) show up in the interface, you can ask Claude to use them. For example: "Could you list all tables in the database?" or "Show me the employees table schema". Claude should invoke the tool and show the result generated by the MCP server. ### Testing with MCP Inspector Test the remote server using [Inspector](https://modelcontextprotocol.io/docs/tools/inspector): ```bash npx @modelcontextprotocol/inspector@latest ``` Enter your server URL and hit connect: - **Local:** `http://localhost:8788/mcp` - **Remote:** `https://<your-remote-mcp-url>/mcp` Once you go through the authentication flow, you'll see the database tools available. ### Using Cursor and Other MCP Clients To connect Cursor with your MCP server, choose `Type`: "Command" and in the `Command` field, combine the command and args fields into one (e.g. `npx mcp-remote https://<your-worker-name>.<your-subdomain>.workers.dev/mcp`). Note that while Cursor supports HTTP+SSE servers, it doesn't support authentication, so you still need to use `mcp-remote` (and to use a STDIO server, not an HTTP one). You can connect your MCP server to other MCP clients like Windsurf by opening the client's configuration file, adding the same JSON that was used for the Claude setup, and restarting the MCP client. ## How does it work? #### OAuth Provider The OAuth Provider library serves as a complete OAuth 2.1 server implementation for Cloudflare Workers. It handles the complexities of the OAuth flow, including token issuance, validation, and management. In this project, it plays the dual role of: - Authenticating MCP clients that connect to your server - Managing the connection to Google Cloud's OAuth services - Securely storing tokens and authentication state in KV storage #### Durable MCP Durable MCP extends the base MCP functionality with Cloudflare's Durable Objects, providing: - Persistent state management for your MCP server - Secure storage of authentication context between requests - Access to authenticated user information via `this.props` - Support for conditional tool availability based on user identity #### MCP Remote The MCP Remote library enables your server to expose tools that can be invoked by MCP clients like the Inspector. It: - Defines the protocol for communication between clients and your server - Provides a structured way to define tools - Handles serialization and deserialization of requests and responses - Supports both Streamable HTTP (recommended) and Server-Sent Events (SSE) protocols for client communication ## Transport Protocol Migration This example has been updated to support the new **Streamable HTTP** transport protocol, which replaces the deprecated Server-Sent Events (SSE) protocol. The server now exposes both endpoints: - `/mcp` - **Recommended**: Uses the new Streamable HTTP protocol - `/sse` - **Deprecated**: Legacy SSE protocol (maintained for backward compatibility) All new integrations should use the `/mcp` endpoint. The SSE endpoint will be removed in a future version.