microsoft · stephentoub · Oct 21, 2025 · Oct 20, 2025 · Oct 21, 2025
@@ -81,7 +81,7 @@
     <PackageVersion Include="Microsoft.SemanticKernel.Planners.OpenAI" Version="1.47.0-preview" />
     <PackageVersion Include="Microsoft.VisualStudio.Threading" Version="17.12.19" />
     <PackageVersion Include="Microsoft.AspNetCore.SignalR.Client" Version="9.0.10" />
-    <PackageVersion Include="ModelContextProtocol" Version="0.3.0-preview.2" />
+    <PackageVersion Include="ModelContextProtocol" Version="0.4.0-preview.3" />
     <PackageVersion Include="MSTest.TestFramework" Version="3.8.0" />
     <PackageVersion Include="Newtonsoft.Json" Version="13.0.4" />
     <PackageVersion Include="Npgsql" Version="8.0.7" />

@@ -33,7 +33,7 @@ public static async Task RunAsync()
         Console.WriteLine($"Running the {nameof(AgentAvailableAsMCPToolSample)} sample.");
 
         // Create an MCP client
-        await using IMcpClient mcpClient = await CreateMcpClientAsync();
+        McpClient mcpClient = await CreateMcpClientAsync();
 
         // Retrieve and display the list provided by the MCP server
         IList<McpClientTool> tools = await mcpClient.ListToolsAsync();

@@ -37,7 +37,7 @@ public static async Task RunAsync()
         Console.WriteLine($"Running the {nameof(AzureAIAgentWithMCPToolsSample)} sample.");
 
         // Create an MCP client
-        await using IMcpClient mcpClient = await CreateMcpClientAsync();
+        McpClient mcpClient = await CreateMcpClientAsync();
 
         // Retrieve and display the list provided by the MCP server
         IList<McpClientTool> tools = await mcpClient.ListToolsAsync();

@@ -21,27 +21,24 @@ internal abstract class BaseSample
     /// <param name="kernel">Optional kernel instance to use for the MCP client.</param>
     /// <param name="samplingRequestHandler">Optional handler for MCP sampling requests.</param>
     /// <returns>An instance of <see cref="IMcpClient"/>.</returns>
-    protected static Task<IMcpClient> CreateMcpClientAsync(
+    protected static Task<McpClient> CreateMcpClientAsync(
         Kernel? kernel = null,
         Func<Kernel, CreateMessageRequestParams?, IProgress<ProgressNotificationValue>, CancellationToken, Task<CreateMessageResult>>? samplingRequestHandler = null)
     {
         KernelFunction? skSamplingHandler = null;
 
         // Create and return the MCP client
-        return McpClientFactory.CreateAsync(
+        return McpClient.CreateAsync(
             clientTransport: new StdioClientTransport(new StdioClientTransportOptions
             {
                 Name = "MCPServer",
                 Command = GetMCPServerPath(), // Path to the MCPServer executable
             }),
             clientOptions: samplingRequestHandler != null ? new McpClientOptions()
             {
-                Capabilities = new ClientCapabilities
+                Handlers = new()
                 {
-                    Sampling = new SamplingCapability
-                    {
-                        SamplingHandler = InvokeHandlerAsync
-                    },
+                    SamplingHandler = InvokeHandlerAsync,
                 },
             } : null
          );

@@ -34,7 +34,7 @@ public static async Task RunAsync()
         Console.WriteLine($"Running the {nameof(ChatCompletionAgentWithMCPToolsSample)} sample.");
 
         // Create an MCP client
-        await using IMcpClient mcpClient = await CreateMcpClientAsync();
+        McpClient mcpClient = await CreateMcpClientAsync();
 
         // Retrieve and display the list provided by the MCP server
         IList<McpClientTool> tools = await mcpClient.ListToolsAsync();

@@ -29,7 +29,7 @@ public static async Task RunAsync()
         Console.WriteLine($"Running the {nameof(MCPPromptSample)} sample.");
 
         // Create an MCP client
-        await using IMcpClient mcpClient = await CreateMcpClientAsync();
+        McpClient mcpClient = await CreateMcpClientAsync();
 
         // Retrieve and display the list of prompts provided by the MCP server
         IList<McpClientPrompt> prompts = await mcpClient.ListPromptsAsync();

@@ -29,7 +29,7 @@ public static async Task RunAsync()
         Console.WriteLine($"Running the {nameof(MCPResourceTemplatesSample)} sample.");
 
         // Create an MCP client
-        await using IMcpClient mcpClient = await CreateMcpClientAsync();
+        McpClient mcpClient = await CreateMcpClientAsync();
 
         // Retrieve list of resource templates provided by the MCP server and display them
         IList<McpClientResourceTemplate> resourceTemplates = await mcpClient.ListResourceTemplatesAsync();
@@ -48,7 +48,7 @@ public static async Task RunAsync()
         string prompt = "What is the Semantic Kernel?";
 
         // Retrieve relevant to the prompt records via MCP resource template
-        ReadResourceResult resource = await mcpClient.ReadResourceAsync($"vectorStore://records/{prompt}");
+        ReadResourceResult resource = await mcpClient.ReadResourceAsync(new Uri($"vectorStore://records/{prompt}"));
 
         // Add the resource content/records to the chat history and prompt the AI model to explain what SK is
         ChatHistory chatHistory = [];

@@ -29,7 +29,7 @@ public static async Task RunAsync()
         Console.WriteLine($"Running the {nameof(MCPResourcesSample)} sample.");
 
         // Create an MCP client
-        await using IMcpClient mcpClient = await CreateMcpClientAsync();
+        McpClient mcpClient = await CreateMcpClientAsync();
 
         // Retrieve list of resources provided by the MCP server and display them
         IList<McpClientResource> resources = await mcpClient.ListResourcesAsync();
@@ -46,7 +46,7 @@ public static async Task RunAsync()
         };
 
         // Retrieve the `image://cat.jpg` resource from the MCP server
-        ReadResourceResult resource = await mcpClient.ReadResourceAsync("image://cat.jpg");
+        ReadResourceResult resource = await mcpClient.ReadResourceAsync(new Uri("image://cat.jpg"));
 
         // Add the resource to the chat history and prompt the AI model to describe the content of the image
         ChatHistory chatHistory = [];

@@ -47,7 +47,7 @@ public static async Task RunAsync()
         kernel.FunctionInvocationFilters.Add(new HumanInTheLoopFilter());
 
         // Create an MCP client with a custom sampling request handler
-        await using IMcpClient mcpClient = await CreateMcpClientAsync(kernel, SamplingRequestHandlerAsync);
+        McpClient mcpClient = await CreateMcpClientAsync(kernel, SamplingRequestHandlerAsync);
 
         // Import MCP tools as Kernel functions so AI model can call them
         IList<McpClientTool> tools = await mcpClient.ListToolsAsync();

@@ -31,7 +31,7 @@ public static async Task RunAsync()
         Console.WriteLine($"Running the {nameof(MCPToolsSample)} sample.");
 
         // Create an MCP client
-        await using IMcpClient mcpClient = await CreateMcpClientAsync();
+        McpClient mcpClient = await CreateMcpClientAsync();
 
         // Retrieve and display the list provided by the MCP server
         IList<McpClientTool> tools = await mcpClient.ListToolsAsync();

@@ -76,10 +76,7 @@ public static ResourceDefinition CreateBlobResource(string uri, string name, byt
     /// <returns>The result of the invocation.</returns>
     public async ValueTask<ReadResourceResult> InvokeHandlerAsync(RequestContext<ReadResourceRequestParams> context, CancellationToken cancellationToken)
     {
-        if (this._kernelFunction == null)
-        {
-            this._kernelFunction = KernelFunctionFactory.CreateFromMethod(this.Handler);
-        }
+        this._kernelFunction ??= KernelFunctionFactory.CreateFromMethod(this.Handler);
 
         this.Kernel
             ??= context.Server.Services?.GetRequiredService<Kernel>()

@@ -17,7 +17,7 @@ internal sealed class MailboxUtils
     /// mechanism for summarization.
     /// </summary>
     [KernelFunction]
-    public static async Task<string> SummarizeUnreadEmailsAsync([FromKernelServices] IMcpServer server)
+    public static async Task<string> SummarizeUnreadEmailsAsync([FromKernelServices] McpServer server)
     {
         if (server.ClientCapabilities?.Sampling is null)
         {

@@ -20,7 +20,7 @@
 }
 
 // Create an MCPClient for the GitHub server
-await using var mcpClient = await McpClientFactory.CreateAsync(new StdioClientTransport(new()
+var mcpClient = await McpClient.CreateAsync(new StdioClientTransport(new()
 {
     Name = "MCPServer",
     Command = "npx",

@@ -36,22 +36,22 @@
     builder.AddConsole();
 });
 
-// Create SSE client transport for the MCP server
+// Create streamable HTTP client transport for the MCP server
 var serverUrl = "http://localhost:7071/";
-var transport = new SseClientTransport(new()
+var transport = new HttpClientTransport(new()
 {
     Endpoint = new Uri(serverUrl),
     Name = "Secure Weather Client",
     OAuth = new()
     {
-        ClientName = "ProtectedMcpClient",
+        ClientId = "ProtectedMcpClient",
         RedirectUri = new Uri("http://localhost:1179/callback"),
         AuthorizationRedirectDelegate = HandleAuthorizationUrlAsync,
     }
 }, httpClient, consoleLoggerFactory);
 
 // Create an MCPClient for the protected MCP server
-await using var mcpClient = await McpClientFactory.CreateAsync(transport, loggerFactory: consoleLoggerFactory);
+await using var mcpClient = await McpClient.CreateAsync(transport, loggerFactory: consoleLoggerFactory);
 
 // Retrieve the list of tools available on the GitHub server
 var tools = await mcpClient.ListToolsAsync().ConfigureAwait(false);