.NET: [Breaking] Delete display name property (#2758)

* delete the AIAgent.DisplayName property

* use agent name as a first value for activity display name

* Update dotnet/src/Microsoft.Agents.AI.Workflows/Specialized/HandoffAgentExecutor.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

dotnet/tests/Microsoft.Agents.AI.A2A.UnitTests/A2AAgentTests.cs

@@ -42,16 +42,14 @@ public sealed class A2AAgentTests : IDisposable
         const string TestId = "test-id";
         const string TestName = "test-name";
         const string TestDescription = "test-description";
-        const string TestDisplayName = "test-display-name";
 
         // Act
-        var agent = new A2AAgent(this._a2aClient, TestId, TestName, TestDescription, TestDisplayName);
+        var agent = new A2AAgent(this._a2aClient, TestId, TestName, TestDescription);
 
         // Assert
         Assert.Equal(TestId, agent.Id);
         Assert.Equal(TestName, agent.Name);
         Assert.Equal(TestDescription, agent.Description);
-        Assert.Equal(TestDisplayName, agent.DisplayName);
     }
 
     [Fact]
@@ -70,7 +68,6 @@ public sealed class A2AAgentTests : IDisposable
         Assert.NotEmpty(agent.Id);
         Assert.Null(agent.Name);
         Assert.Null(agent.Description);
-        Assert.Equal(agent.Id, agent.DisplayName);
     }
 
     [Fact]

dotnet/tests/Microsoft.Agents.AI.A2A.UnitTests/Extensions/A2AClientExtensionsTests.cs

@@ -19,10 +19,9 @@ public sealed class A2AClientExtensionsTests
         const string TestId = "test-agent-id";
         const string TestName = "Test Agent";
         const string TestDescription = "This is a test agent description";
-        const string TestDisplayName = "Test Display Name";
 
         // Act
-        var agent = a2aClient.GetAIAgent(TestId, TestName, TestDescription, TestDisplayName);
+        var agent = a2aClient.GetAIAgent(TestId, TestName, TestDescription);
 
         // Assert
         Assert.NotNull(agent);
@@ -30,6 +29,5 @@ public sealed class A2AClientExtensionsTests
         Assert.Equal(TestId, agent.Id);
         Assert.Equal(TestName, agent.Name);
         Assert.Equal(TestDescription, agent.Description);
-        Assert.Equal(TestDisplayName, agent.DisplayName);
     }
 }

dotnet/tests/Microsoft.Agents.AI.UnitTests/LoggingAgentTests.cs

@@ -42,7 +42,6 @@ public class LoggingAgentTests
         Assert.Equal("TestAgent", agent.Name);
         Assert.Equal("This is a test agent.", agent.Description);
         Assert.Equal(innerAgent.Id, agent.Id);
-        Assert.Equal(innerAgent.DisplayName, agent.DisplayName);
     }
 
     [Fact]

dotnet/tests/Microsoft.Agents.AI.UnitTests/OpenTelemetryAgentTests.cs

@@ -45,7 +45,6 @@ public class OpenTelemetryAgentTests
         Assert.Equal("TestAgent", agent.Name);
         Assert.Equal("This is a test agent.", agent.Description);
         Assert.Equal(innerAgent.Id, agent.Id);
-        Assert.Equal(innerAgent.DisplayName, agent.DisplayName);
     }
 
     [Fact]
@@ -170,7 +169,7 @@ public class OpenTelemetryAgentTests
         Assert.Equal("localhost", activity.GetTagItem("server.address"));
         Assert.Equal(12345, (int)activity.GetTagItem("server.port")!);
 
-        Assert.Equal("invoke_agent TestAgent", activity.DisplayName);
+        Assert.Equal($"invoke_agent {agent.Name}({agent.Id})", activity.DisplayName);
         Assert.Equal("invoke_agent", activity.GetTagItem("gen_ai.operation.name"));
         Assert.Equal("TestAgentProviderFromAIAgentMetadata", activity.GetTagItem("gen_ai.provider.name"));
         Assert.Equal(innerAgent.Name, activity.GetTagItem("gen_ai.agent.name"));
@@ -431,7 +430,15 @@ public class OpenTelemetryAgentTests
         Assert.Equal("localhost", activity.GetTagItem("server.address"));
         Assert.Equal(12345, (int)activity.GetTagItem("server.port")!);
 
-        Assert.Equal($"invoke_agent {innerAgent.DisplayName}", activity.DisplayName);
+        if (string.IsNullOrWhiteSpace(innerAgent.Name))
+        {
+            Assert.Equal($"invoke_agent {innerAgent.Id}", activity.DisplayName);
+        }
+        else
+        {
+            Assert.Equal($"invoke_agent {innerAgent.Name}({innerAgent.Id})", activity.DisplayName);
+        }
+
         Assert.Equal("invoke_agent", activity.GetTagItem("gen_ai.operation.name"));
         Assert.Equal("TestAgentProviderFromAIAgentMetadata", activity.GetTagItem("gen_ai.provider.name"));
         Assert.Equal(innerAgent.Name, activity.GetTagItem("gen_ai.agent.name"));

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/Sample/12_HandOff_HostAsAgent.cs

@@ -30,7 +30,7 @@ internal sealed class HandoffTestEchoAgent(string id, string name, string prefix
                 {
                     return [new(ChatRole.Assistant, [new FunctionCallContent(Guid.NewGuid().ToString("N"), handoff.Name)])
                     {
-                        AuthorName = this.DisplayName,
+                        AuthorName = this.Name ?? this.Id,
                         MessageId = Guid.NewGuid().ToString("N"),
                         CreatedAt = DateTime.UtcNow
                     }];

dotnet/tests/Microsoft.Agents.AI.Workflows.UnitTests/TestEchoAgent.cs

@@ -47,7 +47,7 @@ internal class TestEchoAgent(string? id = null, string? name = null, string? pre
               select
                     UpdateThread(new ChatMessage(ChatRole.Assistant, $"{prefix}{message.Text}")
                     {
-                        AuthorName = this.DisplayName,
+                        AuthorName = this.Name ?? this.Id,
                         CreatedAt = DateTimeOffset.Now,
                         MessageId = Guid.NewGuid().ToString("N")
                     }, thread as InMemoryAgentThread);