Support progress notifications with McpClientTool and McpClientExtensions.CallToolAsync (#312)

src/ModelContextProtocol/Client/McpClientExtensions.cs

@@ -783,9 +783,14 @@ public static class McpClientExtensions
     /// </summary>
     /// <param name="client">The client instance used to communicate with the MCP server.</param>
     /// <param name="toolName">The name of the tool to call on the server..</param>
-    /// <param name="arguments">Optional dictionary of arguments to pass to the tool. Each key represents a parameter name,
+    /// <param name="arguments">An optional dictionary of arguments to pass to the tool. Each key represents a parameter name,
     /// and its associated value represents the argument value.
     /// </param>
+    /// <param name="progress">
+    /// An optional <see cref="IProgress{T}"/> to have progress notifications reported to it. Setting this to a non-<see langword="null"/>
+    /// value will result in a progress token being included in the call, and any resulting progress notifications during the operation
+    /// routed to this instance.
+    /// </param>
     /// <param name="serializerOptions">
     /// The JSON serialization options governing argument serialization. If <see langword="null"/>, the default serialization options will be used.
     /// </param>
@@ -812,6 +817,7 @@ public static class McpClientExtensions
         this IMcpClient client,
         string toolName,
         IReadOnlyDictionary<string, object?>? arguments = null,
+        IProgress<ProgressNotificationValue>? progress = null,
         JsonSerializerOptions? serializerOptions = null,
         CancellationToken cancellationToken = default)
     {
@@ -820,12 +826,56 @@ public static class McpClientExtensions
         serializerOptions ??= McpJsonUtilities.DefaultOptions;
         serializerOptions.MakeReadOnly();
 
+        if (progress is not null)
+        {
+            return SendRequestWithProgressAsync(client, toolName, arguments, progress, serializerOptions, cancellationToken);
+        }
+
         return client.SendRequestAsync(
             RequestMethods.ToolsCall,
-            new() { Name = toolName, Arguments = ToArgumentsDictionary(arguments, serializerOptions) },
+            new()
+            {
+                Name = toolName,
+                Arguments = ToArgumentsDictionary(arguments, serializerOptions),
+            },
             McpJsonUtilities.JsonContext.Default.CallToolRequestParams,
             McpJsonUtilities.JsonContext.Default.CallToolResponse,
             cancellationToken: cancellationToken);
+
+        static async Task<CallToolResponse> SendRequestWithProgressAsync(
+            IMcpClient client,
+            string toolName,
+            IReadOnlyDictionary<string, object?>? arguments,
+            IProgress<ProgressNotificationValue> progress,
+            JsonSerializerOptions serializerOptions,
+            CancellationToken cancellationToken)
+        {
+            ProgressToken progressToken = new(Guid.NewGuid().ToString("N"));
+
+            await using var _ = client.RegisterNotificationHandler(NotificationMethods.ProgressNotification,
+                (notification, cancellationToken) =>
+                {
+                    if (JsonSerializer.Deserialize(notification.Params, McpJsonUtilities.JsonContext.Default.ProgressNotification) is { } pn &&
+                        pn.ProgressToken == progressToken)
+                    {
+                        progress.Report(pn.Progress);
+                    }
+
+                    return default;
+                }).ConfigureAwait(false);
+
+            return await client.SendRequestAsync(
+                RequestMethods.ToolsCall,
+                new()
+                {
+                    Name = toolName,
+                    Arguments = ToArgumentsDictionary(arguments, serializerOptions),
+                    Meta = new() { ProgressToken = progressToken },
+                },
+                McpJsonUtilities.JsonContext.Default.CallToolRequestParams,
+                McpJsonUtilities.JsonContext.Default.CallToolResponse,
+                cancellationToken: cancellationToken).ConfigureAwait(false);
+        }
     }
 
     /// <summary>

src/ModelContextProtocol/Client/McpClientTool.cs

@@ -1,8 +1,9 @@
-using ModelContextProtocol.Protocol.Types;
-using ModelContextProtocol.Utils.Json;
 using Microsoft.Extensions.AI;
-using System.Text.Json;
+using ModelContextProtocol.Protocol.Types;
+using ModelContextProtocol.Utils;
+using ModelContextProtocol.Utils.Json;
 using System.Collections.ObjectModel;
+using System.Text.Json;
 
 namespace ModelContextProtocol.Client;
 
@@ -36,14 +37,22 @@ public sealed class McpClientTool : AIFunction
     private readonly IMcpClient _client;
     private readonly string _name;
     private readonly string _description;
+    private readonly IProgress<ProgressNotificationValue>? _progress;
 
-    internal McpClientTool(IMcpClient client, Tool tool, JsonSerializerOptions serializerOptions, string? name = null, string? description = null)
+    internal McpClientTool(
+        IMcpClient client,
+        Tool tool,
+        JsonSerializerOptions serializerOptions,
+        string? name = null,
+        string? description = null,
+        IProgress<ProgressNotificationValue>? progress = null)
     {
         _client = client;
         ProtocolTool = tool;
         JsonSerializerOptions = serializerOptions;
         _name = name ?? tool.Name;
         _description = description ?? tool.Description ?? string.Empty;
+        _progress = progress;
     }
 
     /// <summary>
@@ -77,7 +86,7 @@ public sealed class McpClientTool : AIFunction
     protected async override ValueTask<object?> InvokeCoreAsync(
         AIFunctionArguments arguments, CancellationToken cancellationToken)
     {
-        CallToolResponse result = await _client.CallToolAsync(ProtocolTool.Name, arguments, JsonSerializerOptions, cancellationToken: cancellationToken).ConfigureAwait(false);
+        CallToolResponse result = await _client.CallToolAsync(ProtocolTool.Name, arguments, _progress, JsonSerializerOptions, cancellationToken: cancellationToken).ConfigureAwait(false);
         return JsonSerializer.SerializeToElement(result, McpJsonUtilities.JsonContext.Default.CallToolResponse);
     }
 
@@ -107,7 +116,7 @@ public sealed class McpClientTool : AIFunction
     /// </remarks>
     public McpClientTool WithName(string name)
     {
-        return new McpClientTool(_client, ProtocolTool, JsonSerializerOptions, name, _description);
+        return new McpClientTool(_client, ProtocolTool, JsonSerializerOptions, name, _description, _progress);
     }
 
     /// <summary>
@@ -133,6 +142,30 @@ public sealed class McpClientTool : AIFunction
     /// <returns>A new instance of <see cref="McpClientTool"/> with the provided description.</returns>
     public McpClientTool WithDescription(string description)
     {
-        return new McpClientTool(_client, ProtocolTool, JsonSerializerOptions, _name, description);
+        return new McpClientTool(_client, ProtocolTool, JsonSerializerOptions, _name, description, _progress);
+    }
+
+    /// <summary>
+    /// Creates a new instance of the tool but modified to report progress via the specified <see cref="IProgress{T}"/>.
+    /// </summary>
+    /// <param name="progress">The <see cref="IProgress{T}"/> to which progress notifications should be reported.</param>
+    /// <remarks>
+    /// <para>
+    /// Adding an <see cref="IProgress{T}"/> to the tool does not impact how it is reported to any AI model.
+    /// Rather, when the tool is invoked, the request to the MCP server will include a unique progress token,
+    /// and any progress notifications issued by the server with that progress token while the operation is in
+    /// flight will be reported to the <paramref name="progress"/> instance.
+    /// </para>
+    /// <para>
+    /// Only one <see cref="IProgress{T}"/> can be specified at a time. Calling <see cref="WithProgress"/> again
+    /// will overwrite any previously specified progress instance.
+    /// </para>
+    /// </remarks>
+    /// <returns>A new instance of <see cref="McpClientTool"/>, configured with the provided progress instance.</returns>
+    public McpClientTool WithProgress(IProgress<ProgressNotificationValue> progress)
+    {
+        Throw.IfNull(progress);
+
+        return new McpClientTool(_client, ProtocolTool, JsonSerializerOptions, _name, _description, progress);
     }
 }

tests/ModelContextProtocol.Tests/Client/McpClientExtensionsTests.cs

@@ -29,7 +29,6 @@ public class McpClientExtensionsTests : ClientServerTestBase
         }
         services.AddSingleton(McpServerTool.Create([McpServerTool(Destructive = false, OpenWorld = true)] (string i) => $"{i} Result", new() { Name = "ValuesSetViaAttr" }));
         services.AddSingleton(McpServerTool.Create([McpServerTool(Destructive = false, OpenWorld = true)] (string i) => $"{i} Result", new() { Name = "ValuesSetViaOptions", Destructive = true, OpenWorld = false, ReadOnly = true }));
-
     }
 
     [Theory]
@@ -209,7 +208,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     [Fact]
     public async Task ListToolsAsync_AllToolsReturned()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
         Assert.Equal(12, tools.Count);
@@ -235,7 +234,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     [Fact]
     public async Task EnumerateToolsAsync_AllToolsReturned()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         await foreach (var tool in client.EnumerateToolsAsync(cancellationToken: TestContext.Current.CancellationToken))
         {
@@ -254,7 +253,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     public async Task EnumerateToolsAsync_FlowsJsonSerializerOptions()
     {
         JsonSerializerOptions options = new(JsonSerializerOptions.Default);
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
         bool hasTools = false;
 
         await foreach (var tool in client.EnumerateToolsAsync(options, TestContext.Current.CancellationToken))
@@ -275,7 +274,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     public async Task EnumerateToolsAsync_HonorsJsonSerializerOptions()
     {
         JsonSerializerOptions emptyOptions = new() { TypeInfoResolver = JsonTypeInfoResolver.Combine() };
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tool = (await client.ListToolsAsync(emptyOptions, TestContext.Current.CancellationToken)).First();
         await Assert.ThrowsAsync<NotSupportedException>(async () => await tool.InvokeAsync(new() { ["i"] = 42 }, TestContext.Current.CancellationToken));
@@ -285,7 +284,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     public async Task SendRequestAsync_HonorsJsonSerializerOptions()
     {
         JsonSerializerOptions emptyOptions = new() { TypeInfoResolver = JsonTypeInfoResolver.Combine() };
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         await Assert.ThrowsAsync<NotSupportedException>(() => client.SendRequestAsync<CallToolRequestParams, CallToolResponse>("Method4", new() { Name = "tool" }, emptyOptions, cancellationToken: TestContext.Current.CancellationToken));
     }
@@ -294,7 +293,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     public async Task SendNotificationAsync_HonorsJsonSerializerOptions()
     {
         JsonSerializerOptions emptyOptions = new() { TypeInfoResolver = JsonTypeInfoResolver.Combine() };
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         await Assert.ThrowsAsync<NotSupportedException>(() => client.SendNotificationAsync("Method4", new { Value = 42 }, emptyOptions, cancellationToken: TestContext.Current.CancellationToken));
     }
@@ -303,7 +302,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     public async Task GetPromptsAsync_HonorsJsonSerializerOptions()
     {
         JsonSerializerOptions emptyOptions = new() { TypeInfoResolver = JsonTypeInfoResolver.Combine() };
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         await Assert.ThrowsAsync<NotSupportedException>(() => client.GetPromptAsync("Prompt", new Dictionary<string, object?> { ["i"] = 42 }, emptyOptions, cancellationToken: TestContext.Current.CancellationToken));
     }
@@ -312,7 +311,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     public async Task WithName_ChangesToolName()
     {
         JsonSerializerOptions options = new(JsonSerializerOptions.Default);
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tool = (await client.ListToolsAsync(options, TestContext.Current.CancellationToken)).First();
         var originalName = tool.Name;
@@ -327,7 +326,7 @@ public class McpClientExtensionsTests : ClientServerTestBase
     public async Task WithDescription_ChangesToolDescription()
     {
         JsonSerializerOptions options = new(JsonSerializerOptions.Default);
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
         var tool = (await client.ListToolsAsync(options, TestContext.Current.CancellationToken)).FirstOrDefault();
         var originalDescription = tool?.Description;
         var redescribedTool = tool?.WithDescription("ToolWithNewDescription");
@@ -336,10 +335,55 @@ public class McpClientExtensionsTests : ClientServerTestBase
         Assert.Equal(originalDescription, tool?.Description);
     }
 
+    [Fact]
+    public async Task WithProgress_ProgressReported()
+    {
+        const int TotalNotifications = 3;
+        int remainingProgress = TotalNotifications;
+        TaskCompletionSource<bool> allProgressReceived = new(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        Server.ServerOptions.Capabilities?.Tools?.ToolCollection?.Add(McpServerTool.Create(async (IProgress<ProgressNotificationValue> progress) =>
+        {
+            for (int i = 0; i < TotalNotifications; i++)
+            {
+                progress.Report(new ProgressNotificationValue { Progress = i * 10, Message = "making progress" });
+                await Task.Delay(1);
+            }
+
+            await allProgressReceived.Task;
+
+            return 42;
+        }, new() { Name = "ProgressReporter" }));
+
+        await using IMcpClient client = await CreateMcpClientForServer();
+
+        var tool = (await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken)).First(t => t.Name == "ProgressReporter");
+
+        IProgress<ProgressNotificationValue> progress = new SynchronousProgress(value =>
+        {
+            Assert.True(value.Progress >= 0 && value.Progress <= 100);
+            Assert.Equal("making progress", value.Message);
+            if (Interlocked.Decrement(ref remainingProgress) == 0)
+            {
+                allProgressReceived.SetResult(true);
+            }
+        });
+
+        Assert.Throws<ArgumentNullException>("progress", () => tool.WithProgress(null!));
+
+        var result = await tool.WithProgress(progress).InvokeAsync(cancellationToken: TestContext.Current.CancellationToken);
+        Assert.Contains("42", result?.ToString());
+    }
+
+    private sealed class SynchronousProgress(Action<ProgressNotificationValue> callback) : IProgress<ProgressNotificationValue>
+    {
+        public void Report(ProgressNotificationValue value) => callback(value);
+    }
+
     [Fact]
     public async Task AsClientLoggerProvider_MessagesSentToClient()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         ILoggerProvider loggerProvider = Server.AsClientLoggerProvider();
         Assert.Throws<ArgumentNullException>("categoryName", () => loggerProvider.CreateLogger(null!));

tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsPromptsTests.cs

@@ -96,7 +96,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
     [Fact]
     public async Task Can_List_And_Call_Registered_Prompts()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var prompts = await client.ListPromptsAsync(TestContext.Current.CancellationToken);
         Assert.Equal(6, prompts.Count);
@@ -125,7 +125,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
     [Fact]
     public async Task Can_Be_Notified_Of_Prompt_Changes()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var prompts = await client.ListPromptsAsync(TestContext.Current.CancellationToken);
         Assert.Equal(6, prompts.Count);
@@ -166,7 +166,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
     [Fact]
     public async Task Throws_When_Prompt_Fails()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         await Assert.ThrowsAsync<McpException>(async () => await client.GetPromptAsync(
             nameof(SimplePrompts.ThrowsException),
@@ -176,7 +176,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
     [Fact]
     public async Task Throws_Exception_On_Unknown_Prompt()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var e = await Assert.ThrowsAsync<McpException>(async () => await client.GetPromptAsync(
             "NotRegisteredPrompt",
@@ -188,7 +188,7 @@ public partial class McpServerBuilderExtensionsPromptsTests : ClientServerTestBa
     [Fact]
     public async Task Throws_Exception_Missing_Parameter()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var e = await Assert.ThrowsAsync<McpException>(async () => await client.GetPromptAsync(
             nameof(SimplePrompts.ReturnsChatMessages),

tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsToolsTests.cs

@@ -124,7 +124,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_List_Registered_Tools()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
         Assert.Equal(16, tools.Count);
@@ -190,7 +190,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Be_Notified_Of_Tool_Changes()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
         Assert.Equal(16, tools.Count);
@@ -231,7 +231,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Call_Registered_Tool()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "Echo",
@@ -249,7 +249,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Call_Registered_Tool_With_Array_Result()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "EchoArray",
@@ -273,7 +273,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Call_Registered_Tool_With_Null_Result()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "ReturnNull",
@@ -287,7 +287,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Call_Registered_Tool_With_Json_Result()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "ReturnJson",
@@ -304,7 +304,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Call_Registered_Tool_With_Int_Result()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "ReturnInteger",
@@ -320,7 +320,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Call_Registered_Tool_And_Pass_ComplexType()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "EchoComplex",
@@ -338,7 +338,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Can_Call_Registered_Tool_With_Instance_Method()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         string[][] parts = new string[2][];
         for (int i = 0; i < 2; i++)
@@ -367,7 +367,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Returns_IsError_Content_When_Tool_Fails()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "ThrowException",
@@ -382,7 +382,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Throws_Exception_On_Unknown_Tool()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var e = await Assert.ThrowsAsync<McpException>(async () => await client.CallToolAsync(
             "NotRegisteredTool",
@@ -394,7 +394,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Returns_IsError_Missing_Parameter()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var result = await client.CallToolAsync(
             "Echo",
@@ -511,7 +511,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task Recognizes_Parameter_Types()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
 
@@ -584,7 +584,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task HandlesIProgressParameter()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
         Assert.NotNull(tools);
@@ -627,7 +627,7 @@ public partial class McpServerBuilderExtensionsToolsTests : ClientServerTestBase
     [Fact]
     public async Task CancellationNotificationsPropagateToToolTokens()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
         Assert.NotNull(tools);

tests/ModelContextProtocol.Tests/Configuration/McpServerScopedTests.cs

@@ -23,7 +23,7 @@ public partial class McpServerScopedTests : ClientServerTestBase
     [Fact]
     public async Task InjectScopedServiceAsArgument()
     {
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(McpServerScopedTestsJsonContext.Default.Options, TestContext.Current.CancellationToken);
         var tool = tools.First(t => t.Name == nameof(EchoTool.EchoComplex));

tests/ModelContextProtocol.Tests/Protocol/CancellationTests.cs

@@ -33,7 +33,7 @@ public class CancellationTests : ClientServerTestBase
     [Fact]
     public async Task PrecancelRequest_CancelsBeforeSending()
     {
-        var client = await CreateMcpClientForServer();
+        await using var client = await CreateMcpClientForServer();
 
         bool gotCancellation = false;
         await using (Server.RegisterNotificationHandler(NotificationMethods.CancelledNotification, (notification, cancellationToken) =>
@@ -51,7 +51,7 @@ public class CancellationTests : ClientServerTestBase
     [Fact]
     public async Task CancellationPropagation_RequestingCancellationCancelsPendingRequest()
     {
-        var client = await CreateMcpClientForServer();
+        await using var client = await CreateMcpClientForServer();
 
         var tools = await client.ListToolsAsync(cancellationToken: TestContext.Current.CancellationToken);
         var waitTool = tools.First(t => t.Name == nameof(WaitForCancellation));

tests/ModelContextProtocol.Tests/Protocol/NotificationHandlerTests.cs

@@ -13,7 +13,7 @@ public class NotificationHandlerTests : ClientServerTestBase
     public async Task RegistrationsAreRemovedWhenDisposed()
     {
         const string NotificationName = "somethingsomething";
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         const int Iterations = 10;
 
@@ -40,7 +40,7 @@ public class NotificationHandlerTests : ClientServerTestBase
     public async Task MultipleRegistrationsResultInMultipleCallbacks()
     {
         const string NotificationName = "somethingsomething";
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         const int RegistrationCount = 10;
 
@@ -80,7 +80,7 @@ public class NotificationHandlerTests : ClientServerTestBase
     public async Task MultipleHandlersRunEvenIfOneThrows()
     {
         const string NotificationName = "somethingsomething";
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         const int RegistrationCount = 10;
 
@@ -122,7 +122,7 @@ public class NotificationHandlerTests : ClientServerTestBase
     public async Task DisposeAsyncDoesNotCompleteWhileNotificationHandlerRuns(int numberOfDisposals)
     {
         const string NotificationName = "somethingsomething";
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var handlerRunning = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
         var releaseHandler = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
@@ -163,7 +163,7 @@ public class NotificationHandlerTests : ClientServerTestBase
     public async Task DisposeAsyncCompletesImmediatelyWhenInvokedFromHandler(int numberOfDisposals)
     {
         const string NotificationName = "somethingsomething";
-        IMcpClient client = await CreateMcpClientForServer();
+        await using IMcpClient client = await CreateMcpClientForServer();
 
         var handlerRunning = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
         var releaseHandler = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);