Add ClientSupportsRoots and ClientSupportsSampling methods

rename SupportsElicitation to ClientSupportsElicitation

Author: dogukandemir

src/ModelContextProtocol.Core/Server/McpServerExtensions.cs

@@ -245,12 +245,46 @@ public static ValueTask<ElicitResult> ElicitAsync(
     /// <remarks>
     /// When <see langword="true"/>, the server can call <see cref="McpServerExtensions.ElicitAsync"/> to request additional information from the user via the client.
     /// </remarks>
-    public static bool SupportsElicitation(this IMcpServer server)
+    public static bool ClientSupportsElicitation(this IMcpServer server)
     {
         Throw.IfNull(server);
         return server.ClientCapabilities?.Elicitation is not null;
     }
 
+    /// <summary>
+    /// Determines whether client supports roots capability.
+    /// </summary>
+    /// <param name="server">McpServer instance to check.</param>
+    /// <returns>
+    /// <see langword="true"/> if client supports roots requests; otherwise, <see langword="false"/>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException"><paramref name="server"/> is <see langword="null"/>.</exception>
+    /// <remarks>
+    /// When <see langword="true"/>, the server can call <see cref="McpServerExtensions.RequestRootsAsync"/> to request the list of roots exposed by the client.
+    /// </remarks>
+    public static bool ClientSupportsRoots(this IMcpServer server)
+    {
+        Throw.IfNull(server);
+        return server.ClientCapabilities?.Roots is not null;
+    }
+
+    /// <summary>
+    /// Determines whether client supports sampling capability.
+    /// </summary>
+    /// <param name="server">McpServer instance to check.</param>
+    /// <returns>
+    /// <see langword="true"/> if client supports sampling requests; otherwise, <see langword="false"/>.
+    /// </returns>
+    /// <exception cref="ArgumentNullException"><paramref name="server"/> is <see langword="null"/>.</exception>
+    /// <remarks>
+    /// When <see langword="true"/>, the server can call sampling methods to request LLM sampling via the client.
+    /// </remarks>
+    public static bool ClientSupportsSampling(this IMcpServer server)
+    {
+        Throw.IfNull(server);
+        return server.ClientCapabilities?.Sampling is not null;
+    }
+
     private static void ThrowIfSamplingUnsupported(IMcpServer server)
     {
         if (server.ClientCapabilities?.Sampling is null)

tests/ModelContextProtocol.Tests/Server/McpServerTests.cs

@@ -178,28 +178,123 @@ public async Task ElicitAsync_Should_Throw_Exception_If_Client_Does_Not_Support_
     }
 
     [Fact]
-    public void SupportsElicitation_Should_Throw_ArgumentNullException_If_Server_Is_Null()
+    public void ClientSupportsElicitation_Should_Throw_ArgumentNullException_If_Server_Is_Null()
     {
         // Arrange
         IMcpServer? server = null;
 
         // Act & Assert
-        Assert.Throws<ArgumentNullException>(() => server!.SupportsElicitation());
+        Assert.Throws<ArgumentNullException>(() => server!.ClientSupportsElicitation());
     }
 
     [Fact]
-    public async Task SupportsElicitation_Should_Return_False_If_ElicitationCapability_Is_Not_Set()
+    public async Task ClientSupportsElicitation_Should_Return_False_If_ElicitationCapability_Is_Not_Set()
     {
         // Arrange
         await using var transport = new TestServerTransport();
         await using var server = McpServerFactory.Create(transport, _options, LoggerFactory);
         SetClientCapabilities(server, new ClientCapabilities { Elicitation = null });
 
         // Act
-        var supportsElicitation = server.SupportsElicitation();
+        var clientSupportsElicitation = server.ClientSupportsElicitation();
 
         // Assert
-        Assert.False(supportsElicitation);
+        Assert.False(clientSupportsElicitation);
+    }
+
+    [Fact]
+    public async Task ClientSupportsElicitation_Should_Return_True_If_ElicitationCapability_Is_Set()
+    {
+        // Arrange
+        await using var transport = new TestServerTransport();
+        await using var server = McpServerFactory.Create(transport, _options, LoggerFactory);
+        SetClientCapabilities(server, new ClientCapabilities { Elicitation = new ElicitationCapability() });
+
+        // Act
+        var clientSupportsElicitation = server.ClientSupportsElicitation();
+
+        // Assert
+        Assert.True(clientSupportsElicitation);
+    }
+
+    [Fact]
+    public void ClientSupportsRoots_Should_Throw_ArgumentNullException_If_Server_Is_Null()
+    {
+        // Arrange
+        IMcpServer? server = null;
+
+        // Act & Assert
+        Assert.Throws<ArgumentNullException>(() => server!.ClientSupportsRoots());
+    }
+
+    [Fact]
+    public async Task ClientSupportsRoots_Should_Return_False_If_RootsCapability_Is_Not_Set()
+    {
+        // Arrange
+        await using var transport = new TestServerTransport();
+        await using var server = McpServerFactory.Create(transport, _options, LoggerFactory);
+        SetClientCapabilities(server, new ClientCapabilities { Roots = null });
+
+        // Act
+        var clientSupportsRoots = server.ClientSupportsRoots();
+
+        // Assert
+        Assert.False(clientSupportsRoots);
+    }
+
+    [Fact]
+    public async Task ClientSupportsRoots_Should_Return_True_If_RootsCapability_Is_Set()
+    {
+        // Arrange
+        await using var transport = new TestServerTransport();
+        await using var server = McpServerFactory.Create(transport, _options, LoggerFactory);
+        SetClientCapabilities(server, new ClientCapabilities { Roots = new RootsCapability() });
+
+        // Act
+        var clientSupportsRoots = server.ClientSupportsRoots();
+
+        // Assert
+        Assert.True(clientSupportsRoots);
+    }
+
+    [Fact]
+    public void ClientSupportsSampling_Should_Throw_ArgumentNullException_If_Server_Is_Null()
+    {
+        // Arrange
+        IMcpServer? server = null;
+
+        // Act & Assert
+        Assert.Throws<ArgumentNullException>(() => server!.ClientSupportsSampling());
+    }
+
+    [Fact]
+    public async Task ClientSupportsSampling_Should_Return_False_If_SamplingCapability_Is_Not_Set()
+    {
+        // Arrange
+        await using var transport = new TestServerTransport();
+        await using var server = McpServerFactory.Create(transport, _options, LoggerFactory);
+        SetClientCapabilities(server, new ClientCapabilities { Sampling = null });
+
+        // Act
+        var clientSupportsSampling = server.ClientSupportsSampling();
+
+        // Assert
+        Assert.False(clientSupportsSampling);
+    }
+
+    [Fact]
+    public async Task ClientSupportsSampling_Should_Return_True_If_SamplingCapability_Is_Set()
+    {
+        // Arrange
+        await using var transport = new TestServerTransport();
+        await using var server = McpServerFactory.Create(transport, _options, LoggerFactory);
+        SetClientCapabilities(server, new ClientCapabilities { Sampling = new SamplingCapability() });
+
+        // Act
+        var clientSupportsSampling = server.ClientSupportsSampling();
+
+        // Assert
+        Assert.True(clientSupportsSampling);
     }
 
     [Fact]