diff --git a/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicBetaServiceExtensionsTests.cs b/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicBetaServiceExtensionsTests.cs
index 71b5f0d282..9836ac8fcf 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicBetaServiceExtensionsTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicBetaServiceExtensionsTests.cs
@@ -452,8 +452,6 @@ public sealed class AnthropicBetaServiceExtensionsTests
 
         public IBetaService Beta => this.BetaService;
 
-        public string? WebhookKey { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
-
         public IBetaService BetaService { get; }
 
         IMessageService IAnthropicClient.Messages => new Mock<IMessageService>().Object;
diff --git a/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicClientExtensionsTests.cs b/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicClientExtensionsTests.cs
index 5df057e8a7..2bff68a5c7 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicClientExtensionsTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Anthropic.UnitTests/Extensions/AnthropicClientExtensionsTests.cs
@@ -82,8 +82,6 @@ public sealed class AnthropicClientExtensionsTests
 
         public IBetaService Beta => throw new NotImplementedException();
 
-        public string? WebhookKey { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
-
         public IAnthropicClient WithOptions(Func<ClientOptions, ClientOptions> modifier)
         {
             throw new NotImplementedException();