Improved samples: added weather tool in AspNetCoreSseServer and option to connect via http to AspNetCoreSseServer. (#469)

Author: sabbadino

samples/AspNetCoreMcpServer/Program.cs

@@ -3,12 +3,14 @@
 using OpenTelemetry.Trace;
 using AspNetCoreMcpServer.Tools;
 using AspNetCoreMcpServer.Resources;
+using System.Net.Http.Headers;
 
 var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddMcpServer()
     .WithHttpTransport()
     .WithTools<EchoTool>()
     .WithTools<SampleLlmTool>()
+    .WithTools<WeatherTools>()
     .WithResources<SimpleResourceType>();
 
 builder.Services.AddOpenTelemetry()
@@ -21,6 +23,13 @@
     .WithLogging()
     .UseOtlpExporter();
 
+// Configure HttpClientFactory for weather.gov API
+builder.Services.AddHttpClient("WeatherApi", client =>
+{
+    client.BaseAddress = new Uri("https://api.weather.gov");
+    client.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("weather-tool", "1.0"));
+});
+
 var app = builder.Build();
 
 app.MapMcp();

samples/AspNetCoreMcpServer/Tools/WeatherTools.cs

@@ -0,0 +1,73 @@
+using ModelContextProtocol;
+using ModelContextProtocol.Server;
+using System.ComponentModel;
+using System.Globalization;
+using System.Text.Json;
+
+namespace AspNetCoreMcpServer.Tools;
+
+[McpServerToolType]
+public sealed class WeatherTools
+{
+    private readonly IHttpClientFactory _httpClientFactory;
+
+    public WeatherTools(IHttpClientFactory httpClientFactory)
+    {
+        _httpClientFactory = httpClientFactory;
+    }
+
+    [McpServerTool, Description("Get weather alerts for a US state.")]
+    public async Task<string> GetAlerts(
+        [Description("The US state to get alerts for. Use the 2 letter abbreviation for the state (e.g. NY).")] string state)
+    {
+        var client = _httpClientFactory.CreateClient("WeatherApi");
+        using var responseStream = await client.GetStreamAsync($"/alerts/active/area/{state}");
+        using var jsonDocument = await JsonDocument.ParseAsync(responseStream)
+            ?? throw new McpException("No JSON returned from alerts endpoint");
+
+        var alerts = jsonDocument.RootElement.GetProperty("features").EnumerateArray();
+
+        if (!alerts.Any())
+        {
+            return "No active alerts for this state.";
+        }
+
+        return string.Join("\n--\n", alerts.Select(alert =>
+        {
+            JsonElement properties = alert.GetProperty("properties");
+            return $"""
+                    Event: {properties.GetProperty("event").GetString()}
+                    Area: {properties.GetProperty("areaDesc").GetString()}
+                    Severity: {properties.GetProperty("severity").GetString()}
+                    Description: {properties.GetProperty("description").GetString()}
+                    Instruction: {properties.GetProperty("instruction").GetString()}
+                    """;
+        }));
+    }
+
+    [McpServerTool, Description("Get weather forecast for a location.")]
+    public async Task<string> GetForecast(
+        [Description("Latitude of the location.")] double latitude,
+        [Description("Longitude of the location.")] double longitude)
+    {
+        var client = _httpClientFactory.CreateClient("WeatherApi");
+        var pointUrl = string.Create(CultureInfo.InvariantCulture, $"/points/{latitude},{longitude}");
+
+        using var locationResponseStream = await client.GetStreamAsync(pointUrl);
+        using var locationDocument = await JsonDocument.ParseAsync(locationResponseStream);
+        var forecastUrl = locationDocument?.RootElement.GetProperty("properties").GetProperty("forecast").GetString()
+            ?? throw new McpException($"No forecast URL provided by {client.BaseAddress}points/{latitude},{longitude}");
+
+        using var forecastResponseStream = await client.GetStreamAsync(forecastUrl);
+        using var forecastDocument = await JsonDocument.ParseAsync(forecastResponseStream);
+        var periods = forecastDocument?.RootElement.GetProperty("properties").GetProperty("periods").EnumerateArray()
+            ?? throw new McpException("No JSON returned from forecast endpoint");
+
+        return string.Join("\n---\n", periods.Select(period => $"""
+                {period.GetProperty("name").GetString()}
+                Temperature: {period.GetProperty("temperature").GetInt32()}°F
+                Wind: {period.GetProperty("windSpeed").GetString()} {period.GetProperty("windDirection").GetString()}
+                Forecast: {period.GetProperty("detailedForecast").GetString()}
+                """));
+    }
+}

samples/QuickstartClient/Program.cs

@@ -5,23 +5,35 @@
 using ModelContextProtocol.Client;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
+using System.Text;
 
 var builder = Host.CreateApplicationBuilder(args);
 
 builder.Configuration
     .AddEnvironmentVariables()
     .AddUserSecrets<Program>();
 
+IClientTransport clientTransport;
 var (command, arguments) = GetCommandAndArguments(args);
 
-var clientTransport = new StdioClientTransport(new()
+if (command == "http")
 {
-    Name = "Demo Server",
-    Command = command,
-    Arguments = arguments,
-});
-
-await using var mcpClient = await McpClientFactory.CreateAsync(clientTransport);
+    // make sure AspNetCoreMcpServer is running
+    clientTransport = new SseClientTransport(new()
+    {
+        Endpoint = new Uri("http://localhost:3001")
+    });
+}
+else
+{
+    clientTransport = new StdioClientTransport(new()
+    {
+        Name = "Demo Server",
+        Command = command,
+        Arguments = arguments,
+    });
+}
+await using var mcpClient = await McpClientFactory.CreateAsync(clientTransport!);
 
 var tools = await mcpClient.ListToolsAsync();
 foreach (var tool in tools)
@@ -46,6 +58,9 @@
 Console.WriteLine("MCP Client Started!");
 Console.ResetColor();
 
+var messages = new List<ChatMessage>();
+var sb = new StringBuilder();
+
 PromptForInput();
 while(Console.ReadLine() is string query && !"exit".Equals(query, StringComparison.OrdinalIgnoreCase))
 {
@@ -55,11 +70,17 @@
         continue;
     }
 
-    await foreach (var message in anthropicClient.GetStreamingResponseAsync(query, options))
+    messages.Add(new ChatMessage(ChatRole.User, query));
+    await foreach (var message in anthropicClient.GetStreamingResponseAsync(messages, options))
     {
         Console.Write(message);
+        sb.Append(message.ToString());
     }
+
     Console.WriteLine();
+    sb.AppendLine();
+    messages.Add(new ChatMessage(ChatRole.Assistant, sb.ToString()));
+    sb.Clear();
 
     PromptForInput();
 }
@@ -79,15 +100,16 @@ static void PromptForInput()
 /// <remarks>
 /// This method uses the file extension of the first argument to determine the command, if it's py, it'll run python,
 /// if it's js, it'll run node, if it's a directory or a csproj file, it'll run dotnet.
-/// 
+///
 /// If no arguments are provided, it defaults to running the QuickstartWeatherServer project from the current repo.
-/// 
+///
 /// This method would only be required if you're creating a generic client, such as we use for the quickstart.
 /// </remarks>
 static (string command, string[] arguments) GetCommandAndArguments(string[] args)
 {
     return args switch
     {
+        [var mode] when mode.Equals("http", StringComparison.OrdinalIgnoreCase) => ("http", args),
         [var script] when script.EndsWith(".py") => ("python", args),
         [var script] when script.EndsWith(".js") => ("node", args),
         [var script] when Directory.Exists(script) || (File.Exists(script) && script.EndsWith(".csproj")) => ("dotnet", ["run", "--project", script]),

samples/QuickstartWeatherServer/Program.cs

@@ -15,11 +15,8 @@
     options.LogToStandardErrorThreshold = LogLevel.Trace;
 });
 
-builder.Services.AddSingleton(_ =>
-{
-    var client = new HttpClient { BaseAddress = new Uri("https://api.weather.gov") };
-    client.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("weather-tool", "1.0"));
-    return client;
-});
+using var httpClient = new HttpClient { BaseAddress = new Uri("https://api.weather.gov") };
+httpClient.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue("weather-tool", "1.0"));
+builder.Services.AddSingleton(httpClient);
 
 await builder.Build().RunAsync();