diff --git a/dotnet/src/Microsoft.AutoGen/Microsoft.AutoGen.Runtime.Grpc/GrpcGateway.cs b/dotnet/src/Microsoft.AutoGen/Microsoft.AutoGen.Runtime.Grpc/GrpcGateway.cs
index 5a3f71ecde0d..427eb4cf0c67 100644
--- a/dotnet/src/Microsoft.AutoGen/Microsoft.AutoGen.Runtime.Grpc/GrpcGateway.cs
+++ b/dotnet/src/Microsoft.AutoGen/Microsoft.AutoGen.Runtime.Grpc/GrpcGateway.cs
@@ -162,20 +162,35 @@ private async ValueTask DispatchEventAsync(CloudEvent evt)
 
     public async ValueTask<RegisterAgentTypeResponse> RegisterAgentTypeAsync(RegisterAgentTypeRequest request)
     {
-        var connection = _workersByConnection[request.RequestId];
-        connection.AddSupportedType(request.Type);
-        _supportedAgentTypes.GetOrAdd(request.Type, _ => []).Add(connection);
-        _agentsToEventsMap.TryAdd(request.Type, new HashSet<string>(request.Events));
+        try
+        {
+            var connection = _workersByConnection[request.RequestId];
+            connection.AddSupportedType(request.Type);
+            _supportedAgentTypes.GetOrAdd(request.Type, _ => []).Add(connection);
+            _agentsToEventsMap.TryAdd(request.Type, new HashSet<string>(request.Events));
 
-        await _gatewayRegistry.RegisterAgentType(request.Type, _reference).ConfigureAwait(true);
-        var response = new RegisterAgentTypeResponse {
-        };
-        return response;
+            await _gatewayRegistry.RegisterAgentType(request.Type, _reference).ConfigureAwait(true);
+            return new RegisterAgentTypeResponse
+            {
+                Success = true,
+                RequestId = request.RequestId
+            };
+        }
+        catch (Exception ex)
+        {
+            return new RegisterAgentTypeResponse
+            {
+                Success = false,
+                RequestId = request.RequestId,
+                Error = ex.Message
+            };
+        }
     }
 
+    // TODO: consider adding this back for backwards compatibility
     //private async ValueTask RegisterAgentTypeAsync(GrpcWorkerConnection connection, RegisterAgentTypeRequest msg)
     //{
-       
+
     //}
 
     private static async Task InvokeRequestDelegate(GrpcWorkerConnection connection, RpcRequest request, Func<RpcRequest, Task<RpcResponse>> func)
diff --git a/dotnet/test/Microsoft.AutoGen.Core.Tests/HandleInterfaceTests.cs b/dotnet/test/Microsoft.AutoGen.Core.Tests/HandleInterfaceTests.cs
index 8cf74a74bf3b..862a42e44ed9 100644
--- a/dotnet/test/Microsoft.AutoGen.Core.Tests/HandleInterfaceTests.cs
+++ b/dotnet/test/Microsoft.AutoGen.Core.Tests/HandleInterfaceTests.cs
@@ -30,7 +30,7 @@ public void Handlers_Supports_Cancellation()
     }
 
     [Fact]
-    public void Can_build_handlers_lookup()
+    public void Can_Build_Handlers_Lookup()
     {
         var source = typeof(TestAgent);
         var handlers = source.GetHandlersLookupTable();
diff --git a/dotnet/test/Microsoft.AutoGen.Core.Tests/Helpers/ClusterFixtureCollection.cs b/dotnet/test/Microsoft.AutoGen.Core.Tests/Helpers/ClusterFixtureCollection.cs
index 5f643410d8be..5d80c25a11be 100644
--- a/dotnet/test/Microsoft.AutoGen.Core.Tests/Helpers/ClusterFixtureCollection.cs
+++ b/dotnet/test/Microsoft.AutoGen.Core.Tests/Helpers/ClusterFixtureCollection.cs
@@ -6,7 +6,7 @@
 namespace Microsoft.AutoGen.Core.Tests.Helpers;
 
 [CollectionDefinition(Name)]
-public sealed class ClusterFixtureCollection : ICollectionFixture<InMemoryAgentRuntimeFixture>
+public sealed class CoreFixtureCollection : ICollectionFixture<InMemoryAgentRuntimeFixture>
 {
-    public const string Name = nameof(ClusterFixtureCollection);
+    public const string Name = nameof(CoreFixtureCollection);
 }
diff --git a/dotnet/test/Microsoft.AutoGen.Core.Tests/InMemoryAgentTests.cs b/dotnet/test/Microsoft.AutoGen.Core.Tests/InMemoryAgentTests.cs
index 7e71342fc71d..564b60b3ec05 100644
--- a/dotnet/test/Microsoft.AutoGen.Core.Tests/InMemoryAgentTests.cs
+++ b/dotnet/test/Microsoft.AutoGen.Core.Tests/InMemoryAgentTests.cs
@@ -11,7 +11,7 @@
 
 namespace Microsoft.AutoGen.Core.Tests;
 
-[Collection(ClusterFixtureCollection.Name)]
+[Collection(CoreFixtureCollection.Name)]
 public partial class InMemoryAgentTests(InMemoryAgentRuntimeFixture fixture)
 {
     private readonly InMemoryAgentRuntimeFixture _fixture = fixture;
diff --git a/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/GrpcGatewayServiceTests.cs b/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/GrpcGatewayServiceTests.cs
index a303d175ef7a..76110d1c29a6 100644
--- a/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/GrpcGatewayServiceTests.cs
+++ b/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/GrpcGatewayServiceTests.cs
@@ -90,21 +90,39 @@ public async Task Test_Message_Goes_To_Right_Worker()
 
     }
 
-    private RegisterAgentTypeRequest CreateRegistrationRequest(EventTypes eventTypes, Type type, string requestId)
+    [Fact]
+    public async Task Test_RegisterAgent_Should_Succeed()
     {
-        var registration = new RegisterAgentTypeRequest
-        {
-            Type = type.Name,
-            RequestId = requestId
-        };
-        registration.Events.AddRange(eventTypes.GetEventsForAgent(type)?.ToList());
+        var logger = Mock.Of<ILogger<GrpcGateway>>();
+        var gateway = new GrpcGateway(_fixture.Cluster.Client, logger);
+        var service = new GrpcGatewayService(gateway);
+        using var client = new TestGrpcClient();
 
-        return registration;
+        var assembly = typeof(PBAgent).Assembly;
+        var eventTypes = ReflectionHelper.GetAgentsMetadata(assembly);
+
+        await service.OpenChannel(client.RequestStream, client.ResponseStream, client.CallContext);
+        var responseMessage = await client.ReadNext();
+
+        var connectionId = responseMessage!.Response.RequestId;
+
+        var response = await service.RegisterAgent(CreateRegistrationRequest(eventTypes, typeof(PBAgent), connectionId), client.CallContext);
+        response.Success.Should().BeTrue();
     }
 
-    private string GetFullName(Type type)
+    [Fact]
+    public async Task Test_RegisterAgent_Should_Fail_For_Wrong_ConnectionId()
     {
-        return ReflectionHelper.GetMessageDescriptor(type)!.FullName;
+        var logger = Mock.Of<ILogger<GrpcGateway>>();
+        var gateway = new GrpcGateway(_fixture.Cluster.Client, logger);
+        var service = new GrpcGatewayService(gateway);
+        using var client = new TestGrpcClient();
+
+        var assembly = typeof(PBAgent).Assembly;
+        var eventTypes = ReflectionHelper.GetAgentsMetadata(assembly);
+
+        var response = await service.RegisterAgent(CreateRegistrationRequest(eventTypes, typeof(PBAgent), "faulty_connection_id"), client.CallContext);
+        response.Success.Should().BeFalse();
     }
 
     [Fact]
@@ -132,4 +150,21 @@ public async Task Test_GetState()
 
         response.Should().NotBeNull();
     }
+
+    private RegisterAgentTypeRequest CreateRegistrationRequest(EventTypes eventTypes, Type type, string requestId)
+    {
+        var registration = new RegisterAgentTypeRequest
+        {
+            Type = type.Name,
+            RequestId = requestId
+        };
+        registration.Events.AddRange(eventTypes.GetEventsForAgent(type)?.ToList());
+
+        return registration;
+    }
+
+    private string GetFullName(Type type)
+    {
+        return ReflectionHelper.GetMessageDescriptor(type)!.FullName;
+    }
 }
diff --git a/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/Helpers/Grpc/TestGrpcClient.cs b/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/Helpers/Grpc/TestGrpcClient.cs
index f839b318b85f..09017c79af17 100644
--- a/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/Helpers/Grpc/TestGrpcClient.cs
+++ b/dotnet/test/Microsoft.AutoGen.Runtime.Grpc.Tests/Helpers/Grpc/TestGrpcClient.cs
@@ -4,7 +4,7 @@
 using Microsoft.AutoGen.Abstractions;
 
 namespace Microsoft.AutoGen.Runtime.Grpc.Tests.Helpers.Grpc;
-internal class TestGrpcClient: IDisposable
+internal sealed class TestGrpcClient: IDisposable
 {
     public TestAsyncStreamReader<Message> RequestStream { get; }
     public TestServerStreamWriter<Message> ResponseStream { get; }