From ceaf9f09d83010d3c573f118ea10238f2614bd28 Mon Sep 17 00:00:00 2001
From: Naveen Chatlapalli <naveen.aifanatic@gmail.com>
Date: Sat, 3 Oct 2026 00:09:27 -0500
Subject: [PATCH] fix: register AG-UI interrupt content in ASP.NET JSON options

---
 .../ConfigureAGUIJsonOptions.cs               |  4 ++
 .../ConfigureAGUIJsonOptionsTests.cs          | 42 +++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/dotnet/src/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore/ConfigureAGUIJsonOptions.cs b/dotnet/src/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore/ConfigureAGUIJsonOptions.cs
index 78eccec92fa..a96cc0e8289 100644
--- a/dotnet/src/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore/ConfigureAGUIJsonOptions.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore/ConfigureAGUIJsonOptions.cs
@@ -29,5 +29,9 @@ public void Configure(JsonOptions options)
         // Agent Framework abstractions follow so that M.E.AI types are handled via its resolver.
         chain.Insert(0, AGUIJsonUtilities.DefaultTypeInfoResolver);
         chain.Insert(1, AgentAbstractionsJsonUtilities.DefaultOptions.TypeInfoResolver!);
+
+        // AG-UI interrupt request/response content is polymorphic AIContent that M.E.AI does not know
+        // about, so it must be registered explicitly or ChatMessage round-trips drop it.
+        AGUIJsonUtilities.RegisterInterruptContentTypes(options.SerializerOptions);
     }
 }
diff --git a/dotnet/tests/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore.UnitTests/ConfigureAGUIJsonOptionsTests.cs b/dotnet/tests/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore.UnitTests/ConfigureAGUIJsonOptionsTests.cs
index 8a6e353f0ba..8ccdb48d095 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore.UnitTests/ConfigureAGUIJsonOptionsTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Hosting.AGUI.AspNetCore.UnitTests/ConfigureAGUIJsonOptionsTests.cs
@@ -45,6 +45,48 @@ public void AddAGUIServer_ConfiguresJsonOptions_OmitsOptionalFieldsWithNoValue()
         Assert.Equal("""{"type":"RUN_STARTED","threadId":"thread","runId":"run"}""", json);
     }
 
+    [Fact]
+    public void AddAGUIServer_ConfiguresJsonOptions_RoundTripsInterruptRequest()
+    {
+        // Arrange
+        JsonSerializerOptions options = BuildConfiguredSerializerOptions();
+        ChatMessage message = new(ChatRole.Assistant, [new InterruptRequestContent("request-1")
+        {
+            Reason = "confirmation",
+            Message = "Approve this action?",
+        }]);
+
+        // Act
+        string json = JsonSerializer.Serialize(message, options);
+        ChatMessage restored = JsonSerializer.Deserialize<ChatMessage>(json, options)!;
+
+        // Assert
+        InterruptRequestContent content = Assert.IsType<InterruptRequestContent>(Assert.Single(restored.Contents));
+        Assert.Equal("request-1", content.RequestId);
+        Assert.Equal("confirmation", content.Reason);
+        Assert.Equal("Approve this action?", content.Message);
+    }
+
+    [Fact]
+    public void AddAGUIServer_ConfiguresJsonOptions_RoundTripsInterruptResponse()
+    {
+        // Arrange
+        JsonSerializerOptions options = BuildConfiguredSerializerOptions();
+        ChatMessage message = new(ChatRole.User, [new InterruptResponseContent("request-1")
+        {
+            Payload = JsonSerializer.SerializeToElement(new { approved = true }),
+        }]);
+
+        // Act
+        string json = JsonSerializer.Serialize(message, options);
+        ChatMessage restored = JsonSerializer.Deserialize<ChatMessage>(json, options)!;
+
+        // Assert
+        InterruptResponseContent content = Assert.IsType<InterruptResponseContent>(Assert.Single(restored.Contents));
+        Assert.Equal("request-1", content.RequestId);
+        Assert.True(Assert.IsType<JsonElement>(content.Payload).GetProperty("approved").GetBoolean());
+    }
+
     private static JsonSerializerOptions BuildConfiguredSerializerOptions()
     {
         ServiceCollection services = new();