diff --git a/src/ModelContextProtocol/ModelContextProtocol.csproj b/src/ModelContextProtocol/ModelContextProtocol.csproj
index 9b9a89ee1..0e677692e 100644
--- a/src/ModelContextProtocol/ModelContextProtocol.csproj
+++ b/src/ModelContextProtocol/ModelContextProtocol.csproj
@@ -13,10 +13,6 @@
     <IsAotCompatible>true</IsAotCompatible>
   </PropertyGroup>
   
-  <ItemGroup>
-    <InternalsVisibleTo Include="ModelContextProtocol.Tests" />
-  </ItemGroup>
-
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.AI.Abstractions"/>
     <PackageReference Include="Microsoft.Extensions.AI" />
diff --git a/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs b/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs
index e8ca56bc4..849ad2ffe 100644
--- a/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs
+++ b/tests/ModelContextProtocol.Tests/Server/McpServerTests.cs
@@ -1,12 +1,13 @@
-using ModelContextProtocol.Client;
+using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Logging;
+using ModelContextProtocol.Client;
 using ModelContextProtocol.Protocol.Messages;
 using ModelContextProtocol.Protocol.Transport;
 using ModelContextProtocol.Protocol.Types;
 using ModelContextProtocol.Server;
 using ModelContextProtocol.Tests.Utils;
-using Microsoft.Extensions.AI;
-using Microsoft.Extensions.Logging;
 using Moq;
+using System.Reflection;
 
 namespace ModelContextProtocol.Tests.Server;
 
@@ -43,7 +44,7 @@ private static McpServerOptions CreateOptions(ServerCapabilities? capabilities =
     public async Task Constructor_Should_Initialize_With_Valid_Parameters()
     {
         // Arrange & Act
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
 
         // Assert
         Assert.NotNull(server);
@@ -53,21 +54,21 @@ public async Task Constructor_Should_Initialize_With_Valid_Parameters()
     public void Constructor_Throws_For_Null_Transport()
     {
         // Arrange, Act & Assert
-        Assert.Throws<ArgumentNullException>(() => new McpServer(null!, _options, _loggerFactory.Object, _serviceProvider));
+        Assert.Throws<ArgumentNullException>(() => McpServerFactory.Create(null!, _options, _loggerFactory.Object, _serviceProvider));
     }
 
     [Fact]
     public void Constructor_Throws_For_Null_Options()
     {
         // Arrange, Act & Assert
-        Assert.Throws<ArgumentNullException>(() => new McpServer(_serverTransport.Object, null!, _loggerFactory.Object, _serviceProvider));
+        Assert.Throws<ArgumentNullException>(() => McpServerFactory.Create(_serverTransport.Object, null!, _loggerFactory.Object, _serviceProvider));
     }
 
     [Fact]
     public async Task Constructor_Does_Not_Throw_For_Null_Logger()
     {
         // Arrange & Act
-        await using var server = new McpServer(_serverTransport.Object, _options, null, _serviceProvider);
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, null, _serviceProvider);
 
         // Assert
         Assert.NotNull(server);
@@ -77,25 +78,17 @@ public async Task Constructor_Does_Not_Throw_For_Null_Logger()
     public async Task Constructor_Does_Not_Throw_For_Null_ServiceProvider()
     {
         // Arrange & Act
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, null);
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, null);
 
         // Assert
         Assert.NotNull(server);
     }
 
-    [Fact]
-    public async Task Property_EndpointName_Return_Infos()
-    {
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
-        server.ClientInfo = new Implementation { Name = "TestClient", Version = "1.1" };
-        Assert.Equal("Server (TestServer 1.0), Client (TestClient 1.1)", server.EndpointName);
-    }
-
     [Fact]
     public async Task StartAsync_Should_Throw_InvalidOperationException_If_Already_Initializing()
     {
         // Arrange
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
         server.GetType().GetField("_isInitializing", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance)?.SetValue(server, true);
 
         // Act & Assert
@@ -106,8 +99,8 @@ public async Task StartAsync_Should_Throw_InvalidOperationException_If_Already_I
     public async Task StartAsync_Should_Do_Nothing_If_Already_Initialized()
     {
         // Arrange
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
-        server.IsInitialized = true;
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
+        SetInitialized(server, true);
 
         await server.StartAsync(TestContext.Current.CancellationToken);
 
@@ -119,7 +112,7 @@ public async Task StartAsync_Should_Do_Nothing_If_Already_Initialized()
     public async Task StartAsync_ShouldStartListening()
     {
         // Arrange
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
 
         // Act
         await server.StartAsync(TestContext.Current.CancellationToken);
@@ -132,7 +125,7 @@ public async Task StartAsync_ShouldStartListening()
     public async Task StartAsync_Sets_Initialized_After_Transport_Responses_Initialized_Notification()
     {
         await using var transport = new TestServerTransport();
-        await using var server = new McpServer(transport, _options, _loggerFactory.Object, _serviceProvider);
+        await using var server = McpServerFactory.Create(transport, _options, _loggerFactory.Object, _serviceProvider);
 
         await server.StartAsync(TestContext.Current.CancellationToken);
 
@@ -152,8 +145,8 @@ await transport.SendMessageAsync(new JsonRpcNotification
     public async Task RequestSamplingAsync_Should_Throw_McpServerException_If_Client_Does_Not_Support_Sampling()
     {
         // Arrange
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
-        server.ClientCapabilities = new ClientCapabilities();
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
+        SetClientCapabilities(server, new ClientCapabilities());
 
         var action = () => server.RequestSamplingAsync(new CreateMessageRequestParams { Messages = [] }, CancellationToken.None);
 
@@ -166,8 +159,8 @@ public async Task RequestSamplingAsync_Should_SendRequest()
     {
         // Arrange
         await using var transport = new TestServerTransport();
-        await using var server = new McpServer(transport, _options, _loggerFactory.Object, _serviceProvider);
-        server.ClientCapabilities = new ClientCapabilities { Sampling = new SamplingCapability() };
+        await using var server = McpServerFactory.Create(transport, _options, _loggerFactory.Object, _serviceProvider);
+        SetClientCapabilities(server, new ClientCapabilities { Sampling = new SamplingCapability() });
 
         await server.StartAsync(TestContext.Current.CancellationToken);
 
@@ -184,8 +177,8 @@ public async Task RequestSamplingAsync_Should_SendRequest()
     public async Task RequestRootsAsync_Should_Throw_McpServerException_If_Client_Does_Not_Support_Roots()
     {
         // Arrange
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
-        server.ClientCapabilities = new ClientCapabilities();
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
+        SetClientCapabilities(server, new ClientCapabilities());
 
         // Act & Assert
         await Assert.ThrowsAsync<ArgumentException>("server", () => server.RequestRootsAsync(new ListRootsRequestParams(), CancellationToken.None));
@@ -196,8 +189,8 @@ public async Task RequestRootsAsync_Should_SendRequest()
     {
         // Arrange
         await using var transport = new TestServerTransport();
-        await using var server = new McpServer(transport, _options, _loggerFactory.Object, _serviceProvider);
-        server.ClientCapabilities = new ClientCapabilities { Roots = new RootsCapability() };
+        await using var server = McpServerFactory.Create(transport, _options, _loggerFactory.Object, _serviceProvider);
+        SetClientCapabilities(server, new ClientCapabilities { Roots = new RootsCapability() });
         await server.StartAsync(TestContext.Current.CancellationToken);
 
         // Act
@@ -213,8 +206,8 @@ public async Task RequestRootsAsync_Should_SendRequest()
     [Fact]
     public async Task Throws_Exception_If_Not_Connected()
     {
-        await using var server = new McpServer(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
-        server.ClientCapabilities = new ClientCapabilities { Roots = new RootsCapability() };
+        await using var server = McpServerFactory.Create(_serverTransport.Object, _options, _loggerFactory.Object, _serviceProvider);
+        SetClientCapabilities(server, new ClientCapabilities { Roots = new RootsCapability() });
         _serverTransport.SetupGet(t => t.IsConnected).Returns(false);
 
         var action = async () => await server.RequestRootsAsync(new ListRootsRequestParams(), CancellationToken.None);
@@ -522,7 +515,7 @@ private async Task Can_Handle_Requests(ServerCapabilities? serverCapabilities, s
         var options = CreateOptions(serverCapabilities);
         configureOptions?.Invoke(options);
 
-        await using var server = new McpServer(transport, options, _loggerFactory.Object, _serviceProvider);
+        await using var server = McpServerFactory.Create(transport, options, _loggerFactory.Object, _serviceProvider);
 
         await server.StartAsync();
 
@@ -595,6 +588,20 @@ public async Task AsSamplingChatClient_HandlesRequestResponse()
         Assert.Equal(ChatRole.Assistant, response.Messages[0].Role);
     }
 
+    private static void SetClientCapabilities(IMcpServer server, ClientCapabilities capabilities)
+    {
+        PropertyInfo? property = server.GetType().GetProperty("ClientCapabilities", BindingFlags.Public | BindingFlags.Instance);
+        Assert.NotNull(property);
+        property.SetValue(server, capabilities);
+    }
+
+    private static void SetInitialized(IMcpServer server, bool isInitialized)
+    {
+        PropertyInfo? property = server.GetType().GetProperty("IsInitialized", BindingFlags.Public | BindingFlags.Instance);
+        Assert.NotNull(property);
+        property.SetValue(server, isInitialized);
+    }
+
     private sealed class TestServerForIChatClient(bool supportsSampling) : IMcpServer
     {
         public ClientCapabilities? ClientCapabilities =>
diff --git a/tests/ModelContextProtocol.Tests/SseIntegrationTests.cs b/tests/ModelContextProtocol.Tests/SseIntegrationTests.cs
index 48f91dcc5..50188cfa1 100644
--- a/tests/ModelContextProtocol.Tests/SseIntegrationTests.cs
+++ b/tests/ModelContextProtocol.Tests/SseIntegrationTests.cs
@@ -1,10 +1,11 @@
-using System.Text.Json;
+using Microsoft.Extensions.Logging;
 using ModelContextProtocol.Client;
 using ModelContextProtocol.Configuration;
 using ModelContextProtocol.Protocol.Transport;
 using ModelContextProtocol.Protocol.Types;
 using ModelContextProtocol.Tests.Utils;
-using Microsoft.Extensions.Logging;
+using System.Reflection;
+using System.Text.Json;
 
 namespace ModelContextProtocol.Tests;
 
@@ -299,8 +300,10 @@ public async Task ConnectTwice_Throws()
             defaultOptions, 
             loggerFactory: loggerFactory,
             cancellationToken: TestContext.Current.CancellationToken);
-        var mcpClient = (McpClient)client;
-        var transport = (SseClientTransport)mcpClient.Transport;
+
+        PropertyInfo? transportProperty = client.GetType().GetProperty("Transport", BindingFlags.NonPublic | BindingFlags.Instance);
+        Assert.NotNull(transportProperty);
+        var transport = (SseClientTransport)transportProperty.GetValue(client)!;
 
         // Wait for SSE connection to be established
         await server.WaitForConnectionAsync(TimeSpan.FromSeconds(10));
diff --git a/tests/ModelContextProtocol.Tests/Transport/SseClientTransportTests.cs b/tests/ModelContextProtocol.Tests/Transport/SseClientTransportTests.cs
index 26aaecd07..0749eed71 100644
--- a/tests/ModelContextProtocol.Tests/Transport/SseClientTransportTests.cs
+++ b/tests/ModelContextProtocol.Tests/Transport/SseClientTransportTests.cs
@@ -1,9 +1,10 @@
-using System.Net;
+using Microsoft.Extensions.Logging.Abstractions;
 using ModelContextProtocol.Configuration;
 using ModelContextProtocol.Protocol.Messages;
 using ModelContextProtocol.Protocol.Transport;
 using ModelContextProtocol.Tests.Utils;
-using Microsoft.Extensions.Logging.Abstractions;
+using System.Net;
+using System.Reflection;
 
 namespace ModelContextProtocol.Tests.Transport;
 
@@ -42,11 +43,16 @@ public async Task Constructor_Should_Initialize_With_Valid_Parameters()
 
         // Assert
         Assert.NotNull(transport);
-        Assert.Equal(TimeSpan.FromSeconds(2), transport.Options.ConnectionTimeout);
-        Assert.Equal(3, transport.Options.MaxReconnectAttempts);
-        Assert.Equal(TimeSpan.FromMilliseconds(50), transport.Options.ReconnectDelay);
-        Assert.NotNull(transport.Options.AdditionalHeaders);
-        Assert.Equal("header", transport.Options.AdditionalHeaders["test"]);
+
+        PropertyInfo? getOptions = transport.GetType().GetProperty("Options", BindingFlags.NonPublic | BindingFlags.Instance);
+        Assert.NotNull(getOptions);
+        var options = (SseClientTransportOptions)getOptions.GetValue(transport)!;
+
+        Assert.Equal(TimeSpan.FromSeconds(2), options.ConnectionTimeout);
+        Assert.Equal(3, options.MaxReconnectAttempts);
+        Assert.Equal(TimeSpan.FromMilliseconds(50), options.ReconnectDelay);
+        Assert.NotNull(options.AdditionalHeaders);
+        Assert.Equal("header", options.AdditionalHeaders["test"]);
     }
 
     [Fact]
@@ -137,7 +143,6 @@ public async Task SendMessageAsync_Throws_Exception_If_MessageEndpoint_Not_Set()
         await using var transport = new SseClientTransport(_transportOptions, _serverConfig, NullLoggerFactory.Instance);
 
         // Assert
-        Assert.True(string.IsNullOrEmpty(transport.MessageEndpoint?.ToString()));
         await Assert.ThrowsAsync<InvalidOperationException>(() => transport.SendMessageAsync(new JsonRpcRequest() { Method = "test" }, CancellationToken.None));
     }