Fix serialization of UserInputRequest/ResponseContent

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputRequestContent.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Text.Json.Serialization;
 using Microsoft.Shared.Diagnostics;
 
 namespace Microsoft.Extensions.AI;
@@ -11,6 +12,9 @@ namespace Microsoft.Extensions.AI;
 /// Represents a request for user input.
 /// </summary>
 [Experimental("MEAI001")]
+[JsonPolymorphic(TypeDiscriminatorPropertyName = "$type")]
+[JsonDerivedType(typeof(FunctionApprovalRequestContent), "functionApprovalRequest")]
+[JsonDerivedType(typeof(McpServerToolApprovalRequestContent), "mcpServerToolApprovalRequest")]
 public class UserInputRequestContent : AIContent
 {
     /// <summary>

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/UserInputResponseContent.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Text.Json.Serialization;
 using Microsoft.Shared.Diagnostics;
 
 namespace Microsoft.Extensions.AI;
@@ -11,6 +12,9 @@ namespace Microsoft.Extensions.AI;
 /// Represents the response to a request for user input.
 /// </summary>
 [Experimental("MEAI001")]
+[JsonPolymorphic(TypeDiscriminatorPropertyName = "$type")]
+[JsonDerivedType(typeof(FunctionApprovalResponseContent), "functionApprovalResponse")]
+[JsonDerivedType(typeof(McpServerToolApprovalResponseContent), "mcpServerToolApprovalResponse")]
 public class UserInputResponseContent : AIContent
 {
     /// <summary>

src/Libraries/Microsoft.Extensions.AI.Abstractions/Utilities/AIJsonUtilities.Defaults.cs

@@ -121,6 +121,8 @@ private static JsonSerializerOptions CreateDefaultOptions()
 
     // Temporary workaround: These should be implicitly added in once they're no longer [Experimental]
     // and are included via [JsonDerivedType] on AIContent.
+    [JsonSerializable(typeof(UserInputRequestContent))]
+    [JsonSerializable(typeof(UserInputResponseContent))]
     [JsonSerializable(typeof(FunctionApprovalRequestContent))]
     [JsonSerializable(typeof(FunctionApprovalResponseContent))]
     [JsonSerializable(typeof(McpServerToolCallContent))]

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalRequestContentTests.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Collections.Generic;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI.Contents;
@@ -51,4 +53,19 @@ public void CreateResponse_ReturnsExpectedResponse(bool approved)
         Assert.Equal(approved, response.Approved);
         Assert.Same(functionCall, response.FunctionCall);
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new FunctionApprovalRequestContent("request123", new FunctionCallContent("call123", "functionName", new Dictionary<string, object?> { { "param1", 123 } }));
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<FunctionApprovalRequestContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.Id, deserializedContent.Id);
+        Assert.NotNull(deserializedContent.FunctionCall);
+        Assert.Equal(content.FunctionCall.CallId, deserializedContent.FunctionCall.CallId);
+        Assert.Equal(content.FunctionCall.Name, deserializedContent.FunctionCall.Name);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/FunctionApprovalResponseContentTests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI.Contents;
@@ -33,4 +34,20 @@ public void Constructor_Roundtrips(string id, bool approved)
         Assert.Equal(approved, content.Approved);
         Assert.Same(functionCall, content.FunctionCall);
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new FunctionApprovalResponseContent("request123", true, new FunctionCallContent("call123", "functionName"));
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<FunctionApprovalResponseContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.Id, deserializedContent.Id);
+        Assert.Equal(content.Approved, deserializedContent.Approved);
+        Assert.NotNull(deserializedContent.FunctionCall);
+        Assert.Equal(content.FunctionCall.CallId, deserializedContent.FunctionCall.CallId);
+        Assert.Equal(content.FunctionCall.Name, deserializedContent.FunctionCall.Name);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/HostedFileContentTests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -49,4 +50,16 @@ public void Constructor_PropsRoundtrip()
         c.AdditionalProperties = props;
         Assert.Same(props, c.AdditionalProperties);
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new HostedFileContent("file123");
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<HostedFileContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.FileId, deserializedContent.FileId);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/HostedVectorStoreContentTests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -49,4 +50,16 @@ public void Constructor_PropsRoundtrip()
         c.AdditionalProperties = props;
         Assert.Same(props, c.AdditionalProperties);
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new HostedVectorStoreContent("vectorstore123");
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<HostedVectorStoreContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.VectorStoreId, deserializedContent.VectorStoreId);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/McpServerToolResultContentTests.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -48,4 +49,20 @@ public void Constructor_Throws()
         Assert.Throws<ArgumentException>("callId", () => new McpServerToolResultContent(string.Empty));
         Assert.Throws<ArgumentNullException>("callId", () => new McpServerToolResultContent(null!));
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new McpServerToolResultContent("call123")
+        {
+            Output = new List<AIContent> { new TextContent("result") }
+        };
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<McpServerToolResultContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.CallId, deserializedContent.CallId);
+        Assert.NotNull(deserializedContent.Output);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/TextContentTests.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -47,4 +48,16 @@ public void Constructor_PropsRoundtrip()
         Assert.Equal(string.Empty, c.Text);
         Assert.Equal(string.Empty, c.ToString());
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new TextContent("Hello, world!");
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<TextContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.Text, deserializedContent.Text);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/TextReasoningContentTests.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -54,4 +55,17 @@ public void Constructor_PropsRoundtrip()
         c.ProtectedData = null;
         Assert.Null(c.ProtectedData);
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new TextReasoningContent("reasoning text") { ProtectedData = "protected" };
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<TextReasoningContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.Text, deserializedContent.Text);
+        Assert.Equal("protected", deserializedContent.ProtectedData);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UsageContentTests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI;
@@ -57,4 +58,24 @@ public void Details_SetNull_Throws()
 
         Assert.Same(d, c.Details);
     }
+
+    [Fact]
+    public void Serialization_Roundtrips()
+    {
+        var content = new UsageContent(new UsageDetails
+        {
+            InputTokenCount = 10,
+            OutputTokenCount = 20,
+            TotalTokenCount = 30
+        });
+
+        var json = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<UsageContent>(json, AIJsonUtilities.DefaultOptions);
+
+        Assert.NotNull(deserializedContent);
+        Assert.NotNull(deserializedContent.Details);
+        Assert.Equal(content.Details.InputTokenCount, deserializedContent.Details.InputTokenCount);
+        Assert.Equal(content.Details.OutputTokenCount, deserializedContent.Details.OutputTokenCount);
+        Assert.Equal(content.Details.TotalTokenCount, deserializedContent.Details.TotalTokenCount);
+    }
 }

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputRequestContentTests.cs

@@ -2,6 +2,9 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI.Contents;
@@ -27,6 +30,33 @@ public void Constructor_Roundtrips(string id)
         Assert.Equal(id, content.Id);
     }
 
+    [Fact]
+    public void Serialization_DerivedTypes_Roundtrips()
+    {
+        UserInputRequestContent content = new FunctionApprovalRequestContent("request123", new FunctionCallContent("call123", "functionName", new Dictionary<string, object?> { { "param1", 123 } }));
+        var serializedContent = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<UserInputRequestContent>(serializedContent, AIJsonUtilities.DefaultOptions);
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.GetType(), deserializedContent.GetType());
+
+        UserInputRequestContent[] contents =
+        [
+            new FunctionApprovalRequestContent("request123", new FunctionCallContent("call123", "functionName", new Dictionary<string, object?> { { "param1", 123 } })),
+            new McpServerToolApprovalRequestContent("request123", new McpServerToolCallContent("call123", "myTool", "myServer")),
+        ];
+
+        var serializedContents = JsonSerializer.Serialize(contents, TestJsonSerializerContext.Default.UserInputRequestContentArray);
+        var deserializedContents = JsonSerializer.Deserialize(serializedContents, TestJsonSerializerContext.Default.UserInputRequestContentArray);
+        Assert.NotNull(deserializedContents);
+
+        Assert.Equal(contents.Count(), deserializedContents.Length);
+        for (int i = 0; i < deserializedContents.Length; i++)
+        {
+            Assert.NotNull(contents.ElementAt(i));
+            Assert.Equal(contents.ElementAt(i).GetType(), deserializedContents[i].GetType());
+        }
+    }
+
     private sealed class TestUserInputRequestContent : UserInputRequestContent
     {
         public TestUserInputRequestContent(string id)

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Contents/UserInputResponseContentTests.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Text.Json;
 using Xunit;
 
 namespace Microsoft.Extensions.AI.Contents;
@@ -27,6 +28,33 @@ public void Constructor_Roundtrips(string id)
         Assert.Equal(id, content.Id);
     }
 
+    [Fact]
+    public void Serialization_DerivedTypes_Roundtrips()
+    {
+        UserInputResponseContent content = new FunctionApprovalResponseContent("request123", true, new FunctionCallContent("call123", "functionName"));
+        var serializedContent = JsonSerializer.Serialize(content, AIJsonUtilities.DefaultOptions);
+        var deserializedContent = JsonSerializer.Deserialize<UserInputResponseContent>(serializedContent, AIJsonUtilities.DefaultOptions);
+        Assert.NotNull(deserializedContent);
+        Assert.Equal(content.GetType(), deserializedContent.GetType());
+
+        UserInputResponseContent[] contents =
+        [
+            new FunctionApprovalResponseContent("request123", true, new FunctionCallContent("call123", "functionName")),
+            new McpServerToolApprovalResponseContent("request123", true),
+        ];
+
+        var serializedContents = JsonSerializer.Serialize(contents, TestJsonSerializerContext.Default.UserInputResponseContentArray);
+        var deserializedContents = JsonSerializer.Deserialize(serializedContents, TestJsonSerializerContext.Default.UserInputResponseContentArray);
+        Assert.NotNull(deserializedContents);
+
+        Assert.Equal(contents.Length, deserializedContents.Length);
+        for (int i = 0; i < deserializedContents.Length; i++)
+        {
+            Assert.NotNull(contents[i]);
+            Assert.Equal(contents[i].GetType(), deserializedContents[i].GetType());
+        }
+    }
+
     private class TestUserInputResponseContent : UserInputResponseContent
     {
         public TestUserInputResponseContent(string id)

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/TestJsonSerializerContext.cs

@@ -39,4 +39,6 @@ namespace Microsoft.Extensions.AI;
 [JsonSerializable(typeof(ChatResponseFormatTests.SomeType))]
 [JsonSerializable(typeof(ChatResponseFormatTests.TypeWithDisplayName))]
 [JsonSerializable(typeof(ResponseContinuationToken))]
+[JsonSerializable(typeof(UserInputRequestContent[]))]
+[JsonSerializable(typeof(UserInputResponseContent[]))]
 internal sealed partial class TestJsonSerializerContext : JsonSerializerContext;