Serverside of MCP Demo

Serverside of the MCP Demo - WeatherServer.Web.Http

First off, I have used the following NuGet packages. I have recently updated the Demo to use .NET 10 and moved from using SSE to Streamable HTTP and verified that it still works after the upgrades.

WeatherServer.Web.Http.csproj Nuget packages:

<ItemGroup>
<PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.3" />
<PackageReference Include="Microsoft.Extensions.Http" Version="10.0.3" />
<PackageReference Include="ModelContextProtocol.AspNetCore" Version="1.1.0" />
<PackageReference Include="Swashbuckle.AspNetCore" Version="10.1.5" />
<PackageReference Include="Swashbuckle.AspNetCore.SwaggerUI" Version="10.1.5" />
<PackageReference Include="ModelContextProtocol" Version="1.1.0" />
<PackageReference Include="Anthropic.SDK" Version="5.10.0" />
<PackageReference Include="Microsoft.Extensions.AI" Version="10.3.0" />
</ItemGroup>

The packages used here are covering different aspects of the MCP protocol and the implementation of the demo.

Anthropic.SDK and ModelContextProtocol are the main packages that are used to implement the MCP protocol and to interact with the Anthropic Claude models.
The ModelContextProtocol.AspNetCore package is used to set up the MCP protocol in an ASP.NET Core web application.
Microsoft.Extensions.AI is used to integrate AI capabilities into the application, allowing us to easily call the Anthropic API and use the Claude models.
Swashbuckle.AspNetCore and Swashbuckle.AspNetCore.SwaggerUI are used to set up Swagger UI for the application, which allows us to visualize the tools and resources that are offered in the MCP protocol.

Program.cs

First off, we add MCP support using AddMcpServer() on builder.Services and then we add the tools we have made and want to expose through the MCP protocol.

We will add three tools in the demo as shown below.

public static void Main(string[] args)
{
    var builder = WebApplication.CreateBuilder(args);

    // Add MCP support
    builder.Services
        .AddMcpServer()
        .WithHttpTransport()
        .WithTools<YrTools>()
        .WithTools<UnitedStatesWeatherTools>()
        .WithTools<NominatimTools>();

Note that assembly scanning is supported, we could have used:

.WithToolsFromAssembly() to add ALL MCP tools in an assembly (project).

I wanted also to be able to run the Server side using Swagger and chat with the Server itself, so a client for the server is actually also set up here.

Further MCP setup is done in Program.cs

  builder.Services.Configure<McpClientOptions>(options =>
  {
      builder.Configuration.GetSection("McpClient");
  });

  var mcpEndpoint = builder.Configuration.GetSection("McpClient:Endpoint").Value;

  builder.Services.AddSingleton<McpClient>(_ =>
  {
      return McpClient.CreateAsync(
          new HttpClientTransport(new HttpClientTransportOptions
          {
              Endpoint = new Uri(mcpEndpoint!),
              TransportMode = HttpTransportMode.StreamableHttp
          })
      ).GetAwaiter().GetResult();
  });

  builder.Services.Configure<ModelContextProtocol.Protocol.Implementation>(options =>
  {
      options.Title = "WeatherMcpDemoServer";
      options.Version = "1.2"; 
  });

We also do more setup with the chat client here, passing in the ANTHROPIC_API_KEY from environment variable and setting up the model to use for chat completions.

// Set up Anthropic client
builder.Services.AddChatClient(_ =>
    new ChatClientBuilder(new AnthropicClient(new APIAuthentication(builder.Configuration["ANTHROPIC_API_KEY"])).Messages)
        .UseFunctionInvocation()
        .Build());

// ..
app.MapMcp("/mcp"); 