diff --git a/src/Tests/Microsoft.Agents.A365.Tooling.Tests/Services/McpClientInitializationTimeoutTests.cs b/src/Tests/Microsoft.Agents.A365.Tooling.Tests/Services/McpClientInitializationTimeoutTests.cs
new file mode 100644
index 00000000..d712ca66
--- /dev/null
+++ b/src/Tests/Microsoft.Agents.A365.Tooling.Tests/Services/McpClientInitializationTimeoutTests.cs
@@ -0,0 +1,181 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using FluentAssertions;
+using Microsoft.Agents.A365.Tooling.Models;
+using Microsoft.Agents.A365.Tooling.Services;
+using Microsoft.Agents.Builder;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using Moq;
+using Xunit;
+
+namespace Microsoft.Agents.A365.Tooling.Tests.Services
+{
+    /// <summary>
+    /// Unit tests for McpClientInitializationTimeoutSeconds in ToolOptions
+    /// and its application in McpToolServerConfigurationService.
+    /// </summary>
+    public class McpClientInitializationTimeoutTests
+    {
+        private readonly Mock<ILogger<IMcpToolServerConfigurationService>> _loggerMock;
+        private readonly Mock<IServiceProvider> _serviceProviderMock;
+        private readonly Mock<IHttpClientFactory> _httpClientFactoryMock;
+
+        public McpClientInitializationTimeoutTests()
+        {
+            _loggerMock = new Mock<ILogger<IMcpToolServerConfigurationService>>();
+            _serviceProviderMock = new Mock<IServiceProvider>();
+            _httpClientFactoryMock = new Mock<IHttpClientFactory>();
+
+            _httpClientFactoryMock.Setup(f => f.CreateClient(It.IsAny<string>()))
+                .Returns(new HttpClient());
+        }
+
+        [Fact]
+        public void ToolOptions_McpClientInitializationTimeoutSeconds_DefaultsToNull()
+        {
+            // Arrange & Act
+            var options = new ToolOptions();
+
+            // Assert
+            options.McpClientInitializationTimeoutSeconds.Should().BeNull();
+        }
+
+        [Fact]
+        public void ToolOptions_McpClientInitializationTimeoutSeconds_CanBeSetToValidValue()
+        {
+            // Arrange & Act
+            var options = new ToolOptions
+            {
+                McpClientInitializationTimeoutSeconds = 180
+            };
+
+            // Assert
+            options.McpClientInitializationTimeoutSeconds.Should().Be(180);
+        }
+
+        [Fact]
+        public void ToolOptions_McpClientInitializationTimeoutSeconds_CanBeSetToNull()
+        {
+            // Arrange
+            var options = new ToolOptions
+            {
+                McpClientInitializationTimeoutSeconds = 120
+            };
+
+            // Act
+            options.McpClientInitializationTimeoutSeconds = null;
+
+            // Assert
+            options.McpClientInitializationTimeoutSeconds.Should().BeNull();
+        }
+
+        [Theory]
+        [InlineData(0)]
+        [InlineData(-1)]
+        [InlineData(-100)]
+        [InlineData(601)]
+        [InlineData(int.MaxValue)]
+        public async Task GetMcpClientToolsAsync_InvalidTimeoutValue_ThrowsArgumentOutOfRangeException(int invalidTimeout)
+        {
+            // Arrange
+            var configMock = new Mock<IConfiguration>();
+            configMock.Setup(c => c["ASPNETCORE_ENVIRONMENT"]).Returns("Development");
+
+            var service = new McpToolServerConfigurationService(
+                _loggerMock.Object,
+                configMock.Object,
+                _serviceProviderMock.Object,
+                _httpClientFactoryMock.Object);
+
+            var serverConfig = new MCPServerConfig
+            {
+                mcpServerName = "test_server",
+                url = "https://localhost:52856/agents/servers/test_server",
+                id = "test-id",
+                scope = "test-scope",
+                audience = "test-audience",
+                publisher = "test-publisher",
+            };
+
+            var toolOptions = new ToolOptions
+            {
+                McpClientInitializationTimeoutSeconds = invalidTimeout
+            };
+
+            var turnContextMock = new Mock<ITurnContext>();
+
+            // Act
+            Func<Task> act = async () => await service.GetMcpClientToolsAsync(
+                turnContextMock.Object, serverConfig, "test-token", toolOptions);
+
+            // Assert - invalid timeout should surface an ArgumentOutOfRangeException either directly
+            // or wrapped by a higher-level InvalidOperationException depending on the call path.
+            var exception = await Record.ExceptionAsync(act);
+            exception.Should().NotBeNull();
+            (exception is ArgumentOutOfRangeException
+                || exception is InvalidOperationException { InnerException: ArgumentOutOfRangeException })
+                .Should().BeTrue("an invalid timeout should result in an ArgumentOutOfRangeException, either directly or wrapped");
+        }
+
+        [Fact]
+        public void GetValidatedInitializationTimeout_NullInput_ReturnsNull()
+        {
+            // Act
+            var result = McpToolServerConfigurationService.GetValidatedInitializationTimeout(null);
+
+            // Assert
+            result.Should().BeNull();
+        }
+
+        [Theory]
+        [InlineData(1)]
+        [InlineData(60)]
+        [InlineData(120)]
+        [InlineData(300)]
+        [InlineData(600)]
+        public void GetValidatedInitializationTimeout_ValidInput_ReturnsMatchingTimeSpan(int seconds)
+        {
+            // Act
+            var result = McpToolServerConfigurationService.GetValidatedInitializationTimeout(seconds);
+
+            // Assert
+            result.Should().Be(TimeSpan.FromSeconds(seconds));
+        }
+
+        [Theory]
+        [InlineData(0)]
+        [InlineData(-1)]
+        [InlineData(-100)]
+        [InlineData(601)]
+        [InlineData(int.MaxValue)]
+        public void GetValidatedInitializationTimeout_InvalidInput_ThrowsArgumentOutOfRangeException(int invalidSeconds)
+        {
+            // Act
+            Action act = () => McpToolServerConfigurationService.GetValidatedInitializationTimeout(invalidSeconds);
+
+            // Assert
+            act.Should().Throw<ArgumentOutOfRangeException>()
+                .Which.ParamName.Should().Be(nameof(ToolOptions.McpClientInitializationTimeoutSeconds));
+        }
+
+        [Theory]
+        [InlineData(1)]
+        [InlineData(60)]
+        [InlineData(120)]
+        [InlineData(300)]
+        [InlineData(600)]
+        public void ToolOptions_McpClientInitializationTimeoutSeconds_AcceptsValidValues(int validTimeout)
+        {
+            // Arrange & Act
+            var options = new ToolOptions
+            {
+                McpClientInitializationTimeoutSeconds = validTimeout
+            };
+
+            // Assert
+            options.McpClientInitializationTimeoutSeconds.Should().Be(validTimeout);
+        }
+    }
+}
diff --git a/src/Tooling/Core/Models/ToolOptions.cs b/src/Tooling/Core/Models/ToolOptions.cs
index 3a63f213..ade9bf3b 100644
--- a/src/Tooling/Core/Models/ToolOptions.cs
+++ b/src/Tooling/Core/Models/ToolOptions.cs
@@ -14,5 +14,15 @@ public class ToolOptions
         /// Gets or sets the user agent configuration for this orchestrator.
         /// </summary>
         public IUserAgentConfiguration? UserAgentConfiguration { get; set; }
+
+        /// <summary>
+        /// Gets or sets the timeout in seconds for MCP client initialization.
+        /// This includes the time for the MCP protocol handshake (initialize/initialized exchange)
+        /// and the underlying HTTP connection. Increase this value if the MCP server performs
+        /// slow operations during initialization (e.g., token exchanges in test environments).
+        /// When null, the MCP SDK default timeout is used.
+        /// Valid range: 1 to 600 seconds. Values outside this range will throw <see cref="ArgumentOutOfRangeException"/>.
+        /// </summary>
+        public int? McpClientInitializationTimeoutSeconds { get; set; }
     }
 }
diff --git a/src/Tooling/Core/Services/McpToolServerConfigurationService.cs b/src/Tooling/Core/Services/McpToolServerConfigurationService.cs
index f5179dab..fd0ea672 100644
--- a/src/Tooling/Core/Services/McpToolServerConfigurationService.cs
+++ b/src/Tooling/Core/Services/McpToolServerConfigurationService.cs
@@ -521,13 +521,34 @@ private async Task<IMcpClient> CreateMcpClientWithAuthHandlers(ITurnContext turn
                 TransportMode = HttpTransportMode.AutoDetect,
             };
 
+            // Validate and compute the initialization timeout once so HttpClient.Timeout
+            // and McpClientOptions.InitializationTimeout always agree.
+            var initializationTimeout = GetValidatedInitializationTimeout(toolOptions.McpClientInitializationTimeoutSeconds);
+
             // Create HTTP client with the authentication handler chain
             var httpClient = new HttpClient(loggingHandler);
 
+            // Apply custom timeout only when explicitly configured
+            if (initializationTimeout.HasValue)
+            {
+                httpClient.Timeout = initializationTimeout.Value;
+            }
+
             var clientTransport = new SseClientTransport(options, httpClient);
 
             try
             {
+                // Only pass McpClientOptions when a custom timeout is set to preserve default SDK behavior
+                if (initializationTimeout.HasValue)
+                {
+                    var clientOptions = new McpClientOptions
+                    {
+                        InitializationTimeout = initializationTimeout.Value,
+                    };
+
+                    return await McpClientFactory.CreateAsync(clientTransport, clientOptions, loggerFactory: this._loggerFactory);
+                }
+
                 return await McpClientFactory.CreateAsync(clientTransport, loggerFactory: this._loggerFactory);
             }
             catch (Exception ex)
@@ -536,6 +557,35 @@ private async Task<IMcpClient> CreateMcpClientWithAuthHandlers(ITurnContext turn
             }
         }
 
+        /// <summary>
+        /// Validates <see cref="ToolOptions.McpClientInitializationTimeoutSeconds"/> and converts it
+        /// to a <see cref="TimeSpan"/>. Returns <c>null</c> when no custom timeout is configured so
+        /// callers can preserve the MCP SDK default behavior.
+        /// </summary>
+        /// <param name="timeoutSeconds">The configured timeout in seconds, or <c>null</c> to use the SDK default.</param>
+        /// <returns>The validated timeout as a <see cref="TimeSpan"/>, or <c>null</c> when not configured.</returns>
+        /// <exception cref="ArgumentOutOfRangeException">
+        /// Thrown when <paramref name="timeoutSeconds"/> is set but falls outside the supported range of 1 to 600 seconds.
+        /// </exception>
+        internal static TimeSpan? GetValidatedInitializationTimeout(int? timeoutSeconds)
+        {
+            if (!timeoutSeconds.HasValue)
+            {
+                return null;
+            }
+
+            var value = timeoutSeconds.Value;
+            if (value < 1 || value > 600)
+            {
+                throw new ArgumentOutOfRangeException(
+                    nameof(ToolOptions.McpClientInitializationTimeoutSeconds),
+                    value,
+                    "McpClientInitializationTimeoutSeconds must be between 1 and 600 seconds.");
+            }
+
+            return TimeSpan.FromSeconds(value);
+        }
+
         /// <summary>
         /// Attaches a per-audience Bearer token to each server's
         /// <see cref="MCPServerConfig.Headers"/> dictionary.