Add [McpServerPrompt] support

Author: stephentoub

Diff for: samples/AspNetCoreSseServer/Program.cs

@@ -1,8 +1,7 @@
-using ModelContextProtocol;
 using AspNetCoreSseServer;
 
 var builder = WebApplication.CreateBuilder(args);
-builder.Services.AddMcpServer().WithToolsFromAssembly();
+builder.Services.AddMcpServer().WithItemsFromAssembly();
 var app = builder.Build();
 
 app.MapGet("/", () => "Hello World!");

Diff for: samples/AspNetCoreSseServer/Tools/EchoTool.cs

@@ -3,7 +3,7 @@
 
 namespace TestServerWithHosting.Tools;
 
-[McpServerToolType]
+[McpServerType]
 public static class EchoTool
 {
     [McpServerTool, Description("Echoes the input back to the client.")]

Diff for: samples/AspNetCoreSseServer/Tools/SampleLlmTool.cs

@@ -7,7 +7,7 @@ namespace TestServerWithHosting.Tools;
 /// <summary>
 /// This tool uses dependency injection and async method
 /// </summary>
-[McpServerToolType]
+[McpServerType]
 public static class SampleLlmTool
 {
     [McpServerTool(Name = "sampleLLM"), Description("Samples from an LLM using MCP's sampling feature")]

Diff for: samples/QuickstartWeatherServer/Program.cs

@@ -1,13 +1,12 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
-using ModelContextProtocol;
 using System.Net.Http.Headers;
 
 var builder = Host.CreateEmptyApplicationBuilder(settings: null);
 
 builder.Services.AddMcpServer()
     .WithStdioServerTransport()
-    .WithToolsFromAssembly();
+    .WithItemsFromAssembly();
 
 builder.Services.AddSingleton(_ =>
 {

Diff for: samples/QuickstartWeatherServer/Tools/WeatherTools.cs

@@ -5,7 +5,7 @@
 
 namespace QuickstartWeatherServer.Tools;
 
-[McpServerToolType]
+[McpServerType]
 public static class WeatherTools
 {
     [McpServerTool, Description("Get weather alerts for a US state.")]

Diff for: samples/TestServerWithHosting/Program.cs

@@ -1,4 +1,4 @@
-using ModelContextProtocol;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Serilog;
 
@@ -19,7 +19,7 @@
     builder.Services.AddSerilog();
     builder.Services.AddMcpServer()
         .WithStdioServerTransport()
-        .WithToolsFromAssembly();
+        .WithItemsFromAssembly();
 
     var app = builder.Build();
 

Diff for: samples/TestServerWithHosting/Tools/EchoTool.cs

@@ -3,7 +3,7 @@
 
 namespace TestServerWithHosting.Tools;
 
-[McpServerToolType]
+[McpServerType]
 public static class EchoTool
 {
     [McpServerTool, Description("Echoes the input back to the client.")]

Diff for: samples/TestServerWithHosting/Tools/SampleLlmTool.cs

@@ -7,7 +7,7 @@ namespace TestServerWithHosting.Tools;
 /// <summary>
 /// This tool uses depenency injection and async method
 /// </summary>
-[McpServerToolType]
+[McpServerType]
 public static class SampleLlmTool
 {
     [McpServerTool(Name = "sampleLLM"), Description("Samples from an LLM using MCP's sampling feature")]

Diff for: src/ModelContextProtocol/AIContentExtensions.cs

@@ -25,6 +25,24 @@ public static ChatMessage ToChatMessage(this PromptMessage promptMessage)
         };
     }
 
+    /// <summary>Gets <see cref="PromptMessage"/> instances for the specified <see cref="ChatMessage"/>.</summary>
+    /// <param name="chatMessage">The message for which to extract its contents as <see cref="PromptMessage"/> instances.</param>
+    /// <returns>The converted content.</returns>
+    public static IEnumerable<PromptMessage> ToPromptMessages(this ChatMessage chatMessage)
+    {
+        Throw.IfNull(chatMessage);
+
+        Role r = chatMessage.Role == ChatRole.User ? Role.User : Role.Assistant;
+
+        foreach (var content in chatMessage.Contents)
+        {
+            if (content is TextContent or DataContent)
+            {
+                yield return new PromptMessage { Role = r, Content = content.ToContent() };
+            }
+        }
+    }
+
     /// <summary>Creates a new <see cref="AIContent"/> from the content of a <see cref="Content"/>.</summary>
     /// <param name="content">The <see cref="Content"/> to convert.</param>
     /// <returns>The created <see cref="AIContent"/>.</returns>

Diff for: src/ModelContextProtocol/Client/McpClient.cs

@@ -1,5 +1,4 @@
-using ModelContextProtocol.Configuration;
-using ModelContextProtocol.Logging;
+using ModelContextProtocol.Logging;
 using ModelContextProtocol.Protocol.Messages;
 using ModelContextProtocol.Protocol.Transport;
 using ModelContextProtocol.Protocol.Types;

Diff for: src/ModelContextProtocol/Client/McpClientFactory.cs

@@ -1,6 +1,5 @@
 using System.Globalization;
 using System.Runtime.InteropServices;
-using ModelContextProtocol.Configuration;
 using ModelContextProtocol.Logging;
 using ModelContextProtocol.Protocol.Transport;
 using ModelContextProtocol.Utils;

Diff for: src/ModelContextProtocol/Configuration/DefaultMcpServerBuilder.cs

@@ -1,12 +1,11 @@
 using ModelContextProtocol.Utils;
-using Microsoft.Extensions.DependencyInjection;
 
-namespace ModelContextProtocol.Configuration;
+namespace Microsoft.Extensions.DependencyInjection;
 
 /// <summary>
 /// Default implementation of <see cref="IMcpServerBuilder"/>.
 /// </summary>
-internal class DefaultMcpServerBuilder : IMcpServerBuilder
+internal sealed class DefaultMcpServerBuilder : IMcpServerBuilder
 {
     /// <inheritdoc/>
     public IServiceCollection Services { get; }

Diff for: src/ModelContextProtocol/Configuration/IMcpServerBuilder.cs

@@ -1,7 +1,6 @@
 using ModelContextProtocol.Server;
-using Microsoft.Extensions.DependencyInjection;
 
-namespace ModelContextProtocol.Configuration;
+namespace Microsoft.Extensions.DependencyInjection;
 
 /// <summary>
 /// Builder for configuring <see cref="IMcpServer"/> instances.