Demo of Model Context Protocol

For more details, please refer to my article:

• Get Start with Model Context Protocol.
• MCP Server and Client with SSE & The New Streamable HTTP
• MCP Authorization: The NEW RS and AS Separation!

Table of Contents

• MCP with stdio
  • server
  • host with clients
• MCP with SSE
  • server
  • client
• MCP with Streamable HTTP
  • server
  • client
• MCP(StreamableHTTP) with Authorization
  • Authorization server
  • MCP Resource server
  • MCP Client

Local MCP with stdio

Local MCP Server

An MCP server that exposes a create-mcp-server-app tool to MCP hosts.

By running this tool, either with Claude for Desktop or some other host, a new project for creating an MCP server with necessary set ups and sample code will be created in the desktop folder.

Sample Code will include the following.

• creating a server instance
• defining available tools
• handling tools execution
• starting the server

Set Up

1. Run npm install to install necessary dependency
2. Run npm run build to build the project
3. build/index.js will the server path to set up in the MCP host

Test with Claude for desktop

1. Download Claude for Desktop
2. Open the configuration file at ~/Library/Application Support/Claude/claude_desktop_config.json
   • If the file does not exist, create one with the same name
3. Add server configuration

{
    "mcpServers": {
        "create-mcp-app": {
            "command": "node",
            "args": [
                "/absolute-path-to/build/index.js"
            ]
        }
    }
}

4. Save the file and restart Claude for Desktop.
5. Enter the prompt create a new mcp server project. You should see a sample MCP Server project created at desktop directory with some responses indicating the success.

Local Host with MCP Clients

An OpenAI-chatbot host that uses MCP clients to connect to MCP servers.

Set up

1. Set up OPENAI_API_KEY in .env.
2. Add MCP server configurations to connect the host in server-config.json.

{
    "some-server-name-1": {
        "command": "node",
        "args": [
            "/absolut-path-to-local-server-folder-1/build/index.js"
        ]
    },
    "some-server-name-2": {
        "command": "uv",
        "args": [
             "--directory",
            "/absolut-path-to-local-server-folder-2",
            "run",
            "main.py"
        ]
    }
}

3. Run npm install to install necessary dependency
4. Run npm run build to build the project
5. Start client by running node build/index.js

Remote MCP with SSE

Remote MCP Server with SSE

An MCP server that is able to connect to multiple client with SSEServerTransport.

Set up

1. Run npm install to install necessary dependency
2. (Optional) Change the endpoint url. By default, the endpoint for connection will be /connect, and that for messaging will be /messages.
3. Run npm run build to build the project
4. Start server by running node build/index.js. This will start a localhost listenining to port 3000.

MCP Client for remote Server with SSE

An MCP client connect to remote server with SSEClientTransport.

Set up

1. Run npm install to install necessary dependency
2. (Optional) Change the server url. By default, it will use http://localhost:3000/connect.
3. Run npm run build to build the project
4. Start client by running node build/index.js.

Remote MCP with Streamable HTTP

Remote MCP Server with Streamable HTTP

An MCP server that is able to connect to multiple client with StreamableHTTPServerTransport.

Features

This server supports:

• Basic functionalities, ie: Client establishing connections and sneding messages (or requests such as list tools, list resources, call tools and etc.) to the server and server responding.
• Standalone SSE to open an SSE stream to support server-initiated messgaes
• Tools
  • A regular tool that return a single response
  • A tool that sends multiple messages back to the client with notifications

Set up

1. Run npm install to install necessary dependency
2. (Optional) Change the endpoint url. By default, the endpoint will be /mcp.
3. Run npm run build to build the project
4. Start server by running node build/index.js. This will start a localhost listenining to port 3000.

MCP Client for remote Server with Streamable Http

An MCP client connect to remote server with SSEClientTransport.

Features

Upon start, the client will

1. Connect to the server
2. Set up notifications to receive update on Logging messages and tool changes
3. List tools and call tools

Set up

1. Run npm install to install necessary dependency
2. (Optional) Change the server url. By default, it will use http://localhost:3000/mcp.
3. Run npm run build to build the project
4. Start client by running node build/index.js.

Remote MCP (Streamable HTTP) + Authorization

This demo is created conforming the new MCP Authorization specifciation where the Authorization Server and Resource server are seperated and the flow consists of four roles

• End user
• MCP Client
• MCP Resource Server
• Authorization Sever

Authorization Server

An OAuth2 authorization server with dynamic client registration implemented using the node-oauth/oauth2-server library.

NOTE: For simplification, instead of an actual database, runtime variables are used in the example to store code/token/user data.

Protocol Endpoints

Basic implementations for the following endpoints are provided conforming to the IETF specifications.

• Authorization endpoint
  • on GET, shows a simple login form to collect user information that will POST to the same endpoint to start authorization flow.
• Token endpoint (for both authorization code exchange and refresh token exchange)
  • Access token generated will be JWT Tokens conforming to JSON Web Token (JWT) Profile for OAuth 2.0 Access Tokens
• Registration endpoint for dynamic client registration
• Revocation endpoint for revoking access tokens and refresh tokens
• /.well-known/oauth-authorization-server for Server Metadata discovery

Other Endpoints

• Error endpoint to display errors related to client's redirect_uri

MCP Resource Server

A Remote MCP Resource Server using StreamableHTTPServerTransport.

Features

• /.well-known/oauth-protected-resource end point for Protected Resource Metadata discovery
• requires Authorization in order to access the following supported features.
  • Basic functionalities, ie: Client establishing connections and sneding messages (or requests such as list tools, list resources, call tools and etc.) to the server and server responding.
  • Tools
    • A regular tool that return a single response
    • A tool that sends multiple messages back to the client with notifications

Authorization (Token validation)

The access token required will be in the form of an JWT Token and the validation is performed by checking the signature, header, and payloads based on the specification(RFC9068).

Errors are handled based on Error Response specification using the WWW-Authenticate Response Header Field

MCP Client

An MCP client connect to remote server with StreamableHTTPClientTransport and providing an OAuthClientProvider to handle authorization as needed.

By using an OAuthClientProvider, the SDK will

1. connect to the server with any existing access token from the provider (OAuthClientProvider.tokens) if there is any or try to connect without specifying any authorization parameters.
2. If the access token has expired, and we try to connect or send messages to the server, for example, by calling listTools, the provider is used to refresh the token.
3. If token refresh fails or no access token exists, and auth is required, OAuthClientProvider is then used to start the authorization flow and an UnauthorizedError will be thrown from connect or the function we used to send messages.

Internal authorization flow managed by OAuthClientProvider:

1. call OAuthClientProvider.clientInformation to try to load any existing client id and secret
2. If not exist and dynamic client registration is supported, try client registration and call OAuthClientProvider.saveClientInformation to save the registered client information
3. Call OAuthClientProvider.redirectToAuthorization with the authorization url
4. After we call transport.finishAuth with the authorization code, exchange the code for access token.

Features

Upon start, the client will

1. Try to Connect to the server without existing authorization info
2. Upon getting an UnauthorizedError and OAuthClientProvider.redirectToAuthorization called, start a local server to receive authorization call back and open the browser with the authorization url
3. Wait for the user to log in to complete and receive authorization code (or error) within the callback
4. Call StreamableHTTPClientTransport.finishAuth with the authorization code to have the SDK to exchange the code for an access token to
5. Upon authorization finish, Reconnect and make some tools calls to confirm the the authorization is successful

A Little Additional

For those who want to manage authorization using other libraries, I have also included some sample code on how to perform the enitre authorization flow using openid-client.

Run the Example

SDK Set up

Since the current Typescript SDK is not supporting the authorization flow from the newest authorization specification yet, I have forked the repository and added some changes.

PS: I have created a PR for it if anyone is being super nice and wants to give it a review!

To test out the examples in this demo

1. Download the auth-client branch of the fork
2. In tsconfig, remove dist from exclude. Ie: "exclude": ["node_modules"]
3. npm run build
4. Use the build as the dependency

Environments

Change the following as needed in .env.

For Client ID Encryption & Decryption

• CIPHER_KEY
• CIPHER_IV
• CIPHER_KEY_ENCODING
• CIPHER_IV_ENCODING

For JWT Token signing

• ACCESS_TOKEN_SIGN_ALGORITHM
• ACCESS_TOKEN_SIGN_SECRET

Other Configurations

Change the following as needed in .

Auth Server

• AUTHORIZATION_SERVER_PORT
• AUTHORIZATION_SERVER_HOSTNAME
• AUTHORIZATION_SERVER_PROTOCOL
• OAUTH_ROUTER_ENDPOINT
• AUTHORIZE_ENDPOINT
• TOKEN_ENDPOINT
• OTHER_ERROR_ENDPOINT
• REVOCATION_ENDPOINT
• REGISTRATION_ENDPOINT
• AUTH_METHODS
• GRANT_TYPES
• MCP_SCOPE
• RESPONSE_TYPES
• CODE_CHALLENGE_METHODS
• ACCESS_TOKEN_LIFETIME
• REFRESH_TOKEN_LIFETIME

Resource Server

• RESOURCE_SERVER_PORT
• RESOURCE_SERVER_PROTOCOL
• RESOURCE_SERVER_HOSTNAME
• MCP_ENDPOINT

Client

• CLIENT_SERVER_PORT
• CLIENT_SERVER_HOSTNAME
• CLIENT_SERVER_PROTOCOL
• CLIENT_SERVER_CALLBACK_PATH

Full Example

Run npm run dev to

• build the project
• start the authorization server
• add some dummy user data (the user that will be logged in to receive access token)
• start the MCP Resource server
• Run the MCP client

Console.log color

• Red: Client
• Blue: Authorization Server
• Green: Resource Server

Authorization Server

Run npm run dev:as to

• build the project
• start the authorization server
• add some dummy user data (the user that will be logged in to receive access token)

MCP Resource Server

Run npm run dev:rs to

• build the project
• start the MCP Resource server

MCP Client

Run npm run dev:client to

• build the project
• Run the MCP client