Fix request-scoped draft client capabilities (#1685)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Tarek Mahmoud Sayed <tarekms@ntdev.microsoft.com>

src/ModelContextProtocol.Core/Server/DestinationBoundMcpServer.cs

@@ -5,18 +5,66 @@ using System.Text.Json.Nodes;
 namespace ModelContextProtocol.Server;
 
 #pragma warning disable MCPEXP002
-internal sealed class DestinationBoundMcpServer(McpServerImpl server, ITransport? transport) : McpServer
+internal sealed class DestinationBoundMcpServer(McpServerImpl server, ITransport? transport, JsonRpcMessageContext? requestContext = null) : McpServer
 #pragma warning restore MCPEXP002
 {
+    private readonly bool _isJuly2026OrLaterRequest = server.IsJuly2026OrLaterProtocolRequest(requestContext);
+    private readonly ClientCapabilities? _requestClientCapabilities = requestContext?.ClientCapabilities;
+    private readonly Implementation? _requestClientInfo = requestContext?.ClientInfo;
+
     public override string? SessionId => transport?.SessionId ?? server.SessionId;
     public override string? NegotiatedProtocolVersion => server.NegotiatedProtocolVersion;
-    public override ClientCapabilities? ClientCapabilities => server.ClientCapabilities;
-    public override Implementation? ClientInfo => server.ClientInfo;
     public override McpServerOptions ServerOptions => server.ServerOptions;
     public override IServiceProvider? Services => server.Services;
     [Obsolete(Obsoletions.DeprecatedLogging_Message, DiagnosticId = Obsoletions.Deprecated_DiagnosticId, UrlFormat = Obsoletions.Deprecated_Url)]
     public override LoggingLevel? LoggingLevel => server.LoggingLevel;
 
+    public override ClientCapabilities? ClientCapabilities
+    {
+        get
+        {
+            // In stateless transport mode, a single request does not have a persistent bidirectional channel.
+            // Server-to-client requests (sampling, roots, elicitation) are unsupported in this mode and the
+            // capability gates rely on a null ClientCapabilities value to report that unsupported-state path.
+            if (!server.HasStatefulTransport())
+            {
+                return null;
+            }
+
+            // On protocol revision 2026-07-28+, client capabilities are request-scoped (_meta on each request)
+            // and must not be inferred from prior requests. Missing per-request capabilities therefore means
+            // "no declared capabilities for this request", represented by an empty object. A fresh instance is
+            // returned deliberately: ClientCapabilities is a mutable DTO handed to user handlers, so a shared
+            // static empty instance could be mutated and leak across requests.
+            if (_isJuly2026OrLaterRequest)
+            {
+                return _requestClientCapabilities ?? new ClientCapabilities();
+            }
+
+            // Legacy protocol behavior uses session-scoped capabilities established during initialize (or
+            // pre-populated migration data), so ignore per-request values and return the server session state.
+            return server.ClientCapabilities;
+        }
+    }
+
+    public override Implementation? ClientInfo
+    {
+        get
+        {
+            // On protocol revision 2026-07-28+, client info is request-scoped (carried in each request's _meta),
+            // mirroring how ClientCapabilities is resolved above. Return only this request's declared value and
+            // do not fall back to shared session state, which under a stateful transport could belong to a
+            // different concurrent request.
+            if (_isJuly2026OrLaterRequest)
+            {
+                return _requestClientInfo;
+            }
+
+            // Legacy protocol behavior uses session-scoped client info established during initialize.
+            return server.ClientInfo;
+        }
+    }
+
     /// <summary>
     /// Gets or sets the MRTR context for the current request, if any.
     /// Set by <see cref="McpServerImpl.CreateDestinationBoundServer"/> when an MRTR-aware handler invocation is in progress.

src/ModelContextProtocol.Core/Server/McpServer.cs

@@ -21,9 +21,19 @@ public abstract partial class McpServer : McpSession
     /// </summary>
     /// <remarks>
     /// <para>
-    /// These capabilities are established during the initialization handshake and indicate
+    /// On protocol revisions that use the <c>initialize</c> handshake (<c>2025-11-25</c> and earlier), these
-    /// which features the client supports, such as sampling, roots, and other
+    /// capabilities are established once during initialization and are session-scoped: they are available both
-    /// protocol-specific functionality.
+    /// on the root <see cref="McpServer"/> and on the server exposed to request handlers.
+    /// </para>
+    /// <para>
+    /// On the <c>2026-07-28</c> revision and later (SEP-2575) there is no <c>initialize</c> handshake; the client
+    /// declares its capabilities per-request in <c>_meta</c>, and the server MUST NOT infer them from previous
+    /// requests. In that mode this property is only meaningful on the request-scoped server accessed via
+    /// the <c>Server</c> property of the <see cref="RequestContext{TParams}"/> passed to a handler; on the
+    /// root <see cref="McpServer"/> (for example one constructed manually over a
+    /// <see cref="System.IO.Stream"/>) it is <see langword="null"/>.
+    /// It is also <see langword="null"/> in stateless transport mode, where server-to-client requests are
+    /// unsupported.
     /// </para>
     /// <para>
     /// Server implementations can check these capabilities to determine which features
@@ -38,7 +48,14 @@ public abstract partial class McpServer : McpSession
     /// <remarks>
     /// <para>
     /// This property contains identification information about the client that has connected to this server,
-    /// including its name and version. This information is provided by the client during initialization.
+    /// including its name and version.
+    /// </para>
+    /// <para>
+    /// On protocol revisions that use the <c>initialize</c> handshake (<c>2025-11-25</c> and earlier) this
+    /// information is provided once during initialization and is session-scoped. On the <c>2026-07-28</c>
+    /// revision and later it is carried per-request in <c>_meta</c>, so read it from the request-scoped server
+    /// accessed via the <c>Server</c> property of the <see cref="RequestContext{TParams}"/> passed to a handler
+    /// rather than from the root <see cref="McpServer"/>.
     /// </para>
     /// <para>
     /// Server implementations can use this information for logging, tracking client versions, 

src/ModelContextProtocol.Core/Server/McpServerImpl.cs

@@ -152,15 +152,17 @@ internal sealed partial class McpServerImpl : McpServer
 
     /// <summary>
     /// Wraps <paramref name="inner"/> so that, for every JSON-RPC request, a built-in filter first
-    /// synchronizes server-side state (<see cref="_negotiatedProtocolVersion"/>,
+    /// synchronizes server-side state (<see cref="_negotiatedProtocolVersion"/>, <see cref="_clientInfo"/>)
-    /// <see cref="_clientCapabilities"/>, <see cref="_clientInfo"/>) from the per-request <c>_meta</c>
+    /// from the per-request <c>_meta</c> values projected onto <see cref="JsonRpcMessageContext"/> and
-    /// values projected onto <see cref="JsonRpcMessageContext"/> and validates the per-request protocol
+    /// validates the per-request protocol version, before delegating to the user-supplied incoming filters.
-    /// version, before delegating to the user-supplied incoming filters.
     /// </summary>
     /// <remarks>
     /// Under the 2026-07-28 protocol revision (SEP-2575) there is no <c>initialize</c> handshake, so these values
-    /// MUST be populated per-request. For legacy clients the per-request values are absent and the built-in
+    /// MUST be populated per-request. Per-request client capabilities and client info are consumed request-scoped
-    /// filter is a no-op (the values were captured during the initialize handler).
+    /// by <see cref="DestinationBoundMcpServer"/> and are not read from server-wide state by request handlers. The
+    /// shared <see cref="_clientInfo"/> write below is best-effort and used only to derive the session endpoint
+    /// name for logging/telemetry. For legacy clients the per-request values are absent and the built-in filter is
+    /// a no-op (the values were captured during the initialize handler).
     /// </remarks>
     private JsonRpcMessageFilter PrependMetaReadingFilter(JsonRpcMessageFilter inner)
     {
@@ -185,23 +187,16 @@ internal sealed partial class McpServerImpl : McpServer
                     SetNegotiatedProtocolVersion(protocolVersion);
                 }
 
-                if (context.ClientCapabilities is { } clientCapabilities && IsJuly2026OrLaterProtocol() && HasStatefulTransport())
-                {
-                    // Under the 2026-07-28 revision the per-request _meta envelope carries the client's FULL
-                    // capabilities (SEP-2575), so a plain overwrite is correct. The IsJuly2026OrLaterProtocol() gate
-                    // makes any legacy per-request envelope a no-op (legacy capabilities stay as the
-                    // initialize handshake established them); the HasStatefulTransport() gate keeps
-                    // _clientCapabilities null under StreamableHttpServerTransport { Stateless = true }
-                    // (where the same server instance handles every request, so persisting per-request
-                    // capability state would both leak across requests and break the StatelessServerTests
-                    // invariant that surfaces the "X is not supported in stateless mode" errors).
-                    _clientCapabilities = clientCapabilities;
-                }
-
                 if (context.ClientInfo is { } clientInfo &&
                     (_clientInfo is null || !string.Equals(_clientInfo.Name, clientInfo.Name, StringComparison.Ordinal) ||
                      !string.Equals(_clientInfo.Version, clientInfo.Version, StringComparison.Ordinal)))
                 {
+                    // This shared write is best-effort and used only to derive the session endpoint name for
+                    // logging/telemetry. It is intentionally NOT read by request handlers on 2026-07-28+ sessions:
+                    // DestinationBoundMcpServer resolves ClientInfo (and ClientCapabilities) request-scoped from
+                    // the per-request _meta so concurrent requests never observe each other's values. Under a
+                    // draft stateful session with differing per-request client info, the last writer wins here,
+                    // which only affects the logged endpoint name and never the request-scoped values handlers see.
                     _clientInfo = clientInfo;
                     endpointNameNeedsRefresh = true;
                 }
@@ -1627,7 +1622,7 @@ internal sealed partial class McpServerImpl : McpServer
 
     private DestinationBoundMcpServer CreateDestinationBoundServer(JsonRpcRequest jsonRpcRequest)
     {
-        var server = new DestinationBoundMcpServer(this, jsonRpcRequest.Context?.RelatedTransport);
+        var server = new DestinationBoundMcpServer(this, jsonRpcRequest.Context?.RelatedTransport, jsonRpcRequest.Context);
 
         if (_mrtrContextsByRequestId.TryRemove(jsonRpcRequest.Id, out var mrtrContext))
         {
@@ -1740,7 +1735,7 @@ internal sealed partial class McpServerImpl : McpServer
             {
                 // Ensure message has a Context so Items can be shared through the pipeline
                 message.Context ??= new();
-                var context = new MessageContext(new DestinationBoundMcpServer(this, message.Context.RelatedTransport), message);
+                var context = new MessageContext(new DestinationBoundMcpServer(this, message.Context.RelatedTransport, message.Context), message);
                 await current(context, cancellationToken).ConfigureAwait(false);
             };
         };
@@ -1795,8 +1790,12 @@ internal sealed partial class McpServerImpl : McpServer
     /// Used to gate the SEP-2663 Tasks extension, which only interoperates on the 2026-07-28 revision.
     /// </summary>
     private bool IsJuly2026OrLaterProtocolRequest(JsonRpcRequest? request) =>
+        IsJuly2026OrLaterProtocolRequest(request?.Context);
+
+    /// <inheritdoc cref="IsJuly2026OrLaterProtocolRequest(JsonRpcRequest?)"/>
+    internal bool IsJuly2026OrLaterProtocolRequest(JsonRpcMessageContext? requestContext) =>
         McpHttpHeaders.IsJuly2026OrLaterProtocolVersion(
-            request?.Context?.ProtocolVersion ?? NegotiatedProtocolVersion);
+            requestContext?.ProtocolVersion ?? NegotiatedProtocolVersion);
 
     /// <inheritdoc />
     public override bool IsMrtrSupported => ClientSupportsMrtr() || HasStatefulTransport();

tests/ModelContextProtocol.Tests/Client/McpClientMetaTests.cs

@@ -3,6 +3,7 @@ using ModelContextProtocol.Client;
 using ModelContextProtocol.Protocol;
 using ModelContextProtocol.Server;
 using ModelContextProtocol.Tests.Utils;
+using System.Text.Json;
 using System.Text.Json.Nodes;
 
 namespace ModelContextProtocol.Tests.Client;
@@ -15,6 +16,9 @@ public class McpClientMetaTests : ClientServerTestBase
 
     private readonly TaskCompletionSource<JsonNode?> _initializeMeta = new();
 
+    private readonly TaskCompletionSource<(Implementation? Info, ClientCapabilities? Capabilities)> _outgoingFilterObserved =
+        new(TaskCreationOptions.RunContinuationsAsynchronously);
+
     public McpClientMetaTests(ITestOutputHelper outputHelper)
         : base(outputHelper)
     {
@@ -39,6 +43,7 @@ public class McpClientMetaTests : ClientServerTestBase
         // Capture the _meta the server receives on the initialize request so tests can
         // assert that McpClientOptions.InitializeMeta is threaded through the handshake.
         mcpServerBuilder.WithMessageFilters(filters =>
+        {
             filters.AddIncomingFilter(next => async (context, cancellationToken) =>
             {
                 if (context.JsonRpcMessage is JsonRpcRequest { Method: RequestMethods.Initialize } request)
@@ -47,7 +52,23 @@ public class McpClientMetaTests : ClientServerTestBase
                 }
 
                 await next(context, cancellationToken);
-            }));
+            });
+
+            // Capture the request-scoped client info/capabilities observed while an outgoing response flows
+            // through the outgoing filter pipeline. Gated on a unique client name so only the dedicated test
+            // triggers it. This exercises that DestinationBoundMcpServer resolves per-request _meta for
+            // responses (whose Context is the originating request's Context), not just requests.
+            filters.AddOutgoingFilter(next => async (context, cancellationToken) =>
+            {
+                if (context.JsonRpcMessage is JsonRpcResponse &&
+                    context.Server.ClientInfo is { Name: "outgoing-filter-client" } info)
+                {
+                    _outgoingFilterObserved.TrySetResult((info, context.Server.ClientCapabilities));
+                }
+
+                await next(context, cancellationToken);
+            });
+        });
     }
 
     [Fact]
@@ -116,6 +137,177 @@ public class McpClientMetaTests : ClientServerTestBase
         Assert.Contains("bar baz", textContent.Text);
     }
 
+    [Fact]
+    public async Task ConcurrentToolCalls_WithPerRequestClientCapabilities_UseRequestScopedCapabilities()
+    {
+        var withSamplingReady = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+        var withoutSamplingReady = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+        var allowSamplingChecks = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        Server.ServerOptions.ToolCollection?.Add(McpServerTool.Create(
+            async (string requestId, RequestContext<CallToolRequestParams> context, CancellationToken cancellationToken) =>
+            {
+                if (requestId == "with")
+                {
+                    withSamplingReady.TrySetResult(true);
+                }
+                else if (requestId == "without")
+                {
+                    withoutSamplingReady.TrySetResult(true);
+                }
+                else
+                {
+                    throw new ArgumentException($"Unexpected request id '{requestId}'.");
+                }
+
+                await allowSamplingChecks.Task.WaitAsync(TestConstants.DefaultTimeout, cancellationToken);
+
+                return context.Server.ClientCapabilities?.Sampling is null ?
+                    $"{requestId}:sampling-absent" :
+                    $"{requestId}:sampling-present";
+            },
+            new() { Name = "meta_sampling_tool" }));
+
+        await using McpClient client = await CreateMcpClientForServer();
+
+        var withSamplingRequest = new CallToolRequestParams
+        {
+            Name = "meta_sampling_tool",
+            Arguments = new Dictionary<string, JsonElement>
+            {
+                ["requestId"] = JsonDocument.Parse("\"with\"").RootElement.Clone(),
+            },
+            Meta = new JsonObject
+            {
+                [MetaKeys.ClientCapabilities] = JsonSerializer.SerializeToNode(
+                    new ClientCapabilities { Sampling = new SamplingCapability() },
+                    McpJsonUtilities.DefaultOptions),
+            },
+        };
+
+        var withoutSamplingRequest = new CallToolRequestParams
+        {
+            Name = "meta_sampling_tool",
+            Arguments = new Dictionary<string, JsonElement>
+            {
+                ["requestId"] = JsonDocument.Parse("\"without\"").RootElement.Clone(),
+            },
+            Meta = new JsonObject
+            {
+                [MetaKeys.ClientCapabilities] = JsonSerializer.SerializeToNode(
+                    new ClientCapabilities(),
+                    McpJsonUtilities.DefaultOptions),
+            },
+        };
+
+        Task<CallToolResult> withSamplingTask = client.CallToolAsync(withSamplingRequest, TestContext.Current.CancellationToken).AsTask();
+        Task<CallToolResult> withoutSamplingTask = client.CallToolAsync(withoutSamplingRequest, TestContext.Current.CancellationToken).AsTask();
+
+        await Task.WhenAll(withSamplingReady.Task, withoutSamplingReady.Task).WaitAsync(TestConstants.DefaultTimeout, TestContext.Current.CancellationToken);
+        allowSamplingChecks.TrySetResult(true);
+
+        CallToolResult withSamplingResult = await withSamplingTask;
+        CallToolResult withoutSamplingResult = await withoutSamplingTask;
+
+        var withSamplingText = Assert.IsType<TextContentBlock>(Assert.Single(withSamplingResult.Content)).Text;
+        var withoutSamplingText = Assert.IsType<TextContentBlock>(Assert.Single(withoutSamplingResult.Content)).Text;
+
+        Assert.Equal("with:sampling-present", withSamplingText);
+        Assert.Equal("without:sampling-absent", withoutSamplingText);
+    }
+
+    [Fact]
+    public async Task ToolCall_UnderJuly2026Protocol_ObservesRequestScopedClientInfo()
+    {
+        Server.ServerOptions.ToolCollection?.Add(McpServerTool.Create(
+            (RequestContext<CallToolRequestParams> context) =>
+            {
+                var clientInfo = context.Server.ClientInfo;
+                return clientInfo is null ?
+                    "client-info-absent" :
+                    $"{clientInfo.Name}:{clientInfo.Version}";
+            },
+            new() { Name = "client_info_tool" }));
+
+        // The 2026-07-28+ client stamps its ClientInfo onto every request's _meta, so the tool must observe
+        // the per-request value resolved by DestinationBoundMcpServer rather than server-only session state.
+        var clientOptions = new McpClientOptions
+        {
+            ClientInfo = new Implementation { Name = "request-scoped-client", Version = "9.9.9" },
+        };
+
+        await using McpClient client = await CreateMcpClientForServer(clientOptions);
+
+        var result = await client.CallToolAsync("client_info_tool", cancellationToken: TestContext.Current.CancellationToken);
+
+        var text = Assert.IsType<TextContentBlock>(Assert.Single(result.Content)).Text;
+        Assert.Equal("request-scoped-client:9.9.9", text);
+    }
+
+    [Fact]
+    public async Task RootServer_UnderJuly2026Protocol_HasNoClientCapabilities_ButHandlerObservesThem()
+    {
+        ClientCapabilities? handlerObservedCapabilities = null;
+
+        Server.ServerOptions.ToolCollection?.Add(McpServerTool.Create(
+            (RequestContext<CallToolRequestParams> context) =>
+            {
+                handlerObservedCapabilities = context.Server.ClientCapabilities;
+                return "ok";
+            },
+            new() { Name = "capability_probe_tool" }));
+
+        var clientOptions = new McpClientOptions
+        {
+            Handlers = new McpClientHandlers
+            {
+                ElicitationHandler = (_, _) => new ValueTask<ElicitResult>(new ElicitResult()),
+            },
+        };
+
+        await using McpClient client = await CreateMcpClientForServer(clientOptions);
+
+        // Under the 2026-07-28 revision capabilities are request-scoped, so the root server (outside any
+        // request) never exposes them, whereas a request handler observes the per-request _meta values.
+        Assert.Null(Server.ClientCapabilities);
+
+        await client.CallToolAsync("capability_probe_tool", cancellationToken: TestContext.Current.CancellationToken);
+
+        Assert.NotNull(handlerObservedCapabilities);
+        Assert.NotNull(handlerObservedCapabilities!.Elicitation);
+        Assert.Null(Server.ClientCapabilities);
+    }
+
+    [Fact]
+    public async Task OutgoingMessageFilter_UnderJuly2026Protocol_ObservesRequestScopedClientInfoAndCapabilities()
+    {
+        Server.ServerOptions.ToolCollection?.Add(McpServerTool.Create(
+            () => "ok",
+            new() { Name = "outgoing_probe_tool" }));
+
+        var clientOptions = new McpClientOptions
+        {
+            ClientInfo = new Implementation { Name = "outgoing-filter-client", Version = "3.2.1" },
+            Handlers = new McpClientHandlers
+            {
+                ElicitationHandler = (_, _) => new ValueTask<ElicitResult>(new ElicitResult()),
+            },
+        };
+
+        await using McpClient client = await CreateMcpClientForServer(clientOptions);
+
+        await client.CallToolAsync("outgoing_probe_tool", cancellationToken: TestContext.Current.CancellationToken);
+
+        var (info, capabilities) = await _outgoingFilterObserved.Task
+            .WaitAsync(TestConstants.DefaultTimeout, TestContext.Current.CancellationToken);
+
+        Assert.NotNull(info);
+        Assert.Equal("outgoing-filter-client", info!.Name);
+        Assert.Equal("3.2.1", info.Version);
+        Assert.NotNull(capabilities);
+        Assert.NotNull(capabilities!.Elicitation);
+    }
+
     [Fact]
     public async Task ResourceReadWithMetaFields()
     {

tests/ModelContextProtocol.Tests/Protocol/UrlElicitationTests.cs

@@ -190,6 +190,16 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
         });
     }
 
+    // These tests assert on the root server's ClientCapabilities (see AssertServerElicitationCapability),
+    // which is only session-scoped under the initialize-handshake revisions. Pin to the latest such revision
+    // so the capabilities negotiated during initialize are observable on the root McpServer. Request-scoped
+    // capability behavior under the 2026-07-28 revision is covered by McpClientMetaTests.
+    private Task<McpClient> CreateLegacyClientForServer(McpClientOptions clientOptions)
+    {
+        clientOptions.ProtocolVersion = McpHttpHeaders.November2025ProtocolVersion;
+        return CreateMcpClientForServer(clientOptions);
+    }
+
     [Fact]
     public async Task Can_Elicit_OutOfBand_With_Url()
     {
@@ -198,7 +208,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
         string? capturedMessage = null;
         var completionNotification = new TaskCompletionSource<string?>(TaskCreationOptions.RunContinuationsAsynchronously);
 
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {
@@ -283,7 +293,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     [Fact]
     public async Task UrlElicitation_User_Can_Decline()
     {
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {
@@ -322,7 +332,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     [Fact]
     public async Task UrlElicitation_User_Can_Cancel()
     {
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {
@@ -360,7 +370,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     [Fact]
     public async Task UrlElicitation_Defaults_To_Unsupported_When_Handler_Provided()
     {
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Handlers = new McpClientHandlers()
             {
@@ -385,7 +395,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     [Fact]
     public async Task FormElicitation_Defaults_To_Supported_When_Handler_Provided()
     {
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Handlers = new McpClientHandlers()
             {
@@ -406,7 +416,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     [Fact]
     public async Task UrlElicitation_BlankCapability_Allows_Only_Form()
     {
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {
@@ -435,7 +445,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     [Fact]
     public async Task FormElicitation_UrlOnlyCapability_NotSupported()
     {
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {
@@ -474,7 +484,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     {
         var elicitationHandlerCalled = false;
 
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {
@@ -504,7 +514,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     [Fact]
     public async Task UrlElicitationRequired_Exception_Propagates_To_Client()
     {
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {
@@ -532,7 +542,7 @@ public partial class UrlElicitationTests(ITestOutputHelper testOutputHelper) : C
     {
         var elicitationHandlerCalled = false;
 
-        await using McpClient client = await CreateMcpClientForServer(new McpClientOptions
+        await using McpClient client = await CreateLegacyClientForServer(new McpClientOptions
         {
             Capabilities = new ClientCapabilities
             {