.NET: Make serialize methods sync and rename one to match others. (#946)

* Make serialize methods sync and rename one to match others.

* Remove unnecessary async postfixes.

* Remove nullability of ChatMessageStore.Serialize return type, since the default JsonElement already represents an undefined json element.

* Fix unit test

dotnet/samples/GettingStarted/Agents/Agent_Step06_PersistedConversations/Program.cs

@@ -30,7 +30,7 @@ AgentThread thread = agent.GetNewThread();
 Console.WriteLine(await agent.RunAsync("Tell me a joke about a pirate.", thread));
 
 // Serialize the thread state to a JsonElement, so it can be stored for later use.
-JsonElement serializedThread = await thread.SerializeAsync();
+JsonElement serializedThread = thread.Serialize();
 
 // Save the serialized thread to a temporary file (for demonstration purposes).
 string tempFilePath = Path.GetTempFileName();

dotnet/samples/GettingStarted/Agents/Agent_Step07_3rdPartyThreadStorage/Program.cs

@@ -56,7 +56,7 @@ Console.WriteLine(await agent.RunAsync("Tell me a joke about a pirate.", thread)
 // Serialize the thread state, so it can be stored for later use.
 // Since the chat history is stored in the vector store, the serialized thread
 // only contains the guid that the messages are stored under in the vector store.
-JsonElement serializedThread = await thread.SerializeAsync();
+JsonElement serializedThread = thread.Serialize();
 
 Console.WriteLine("\n--- Serialized thread ---\n");
 Console.WriteLine(JsonSerializer.Serialize(serializedThread, new JsonSerializerOptions { WriteIndented = true }));
@@ -131,9 +131,9 @@ namespace SampleApp
             return messages;
         }
 
-        public override ValueTask<JsonElement?> SerializeStateAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default) =>
+        public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null) =>
             // We have to serialize the thread id, so that on deserialization we can retrieve the messages using the same thread id.
-            new(JsonSerializer.SerializeToElement(this.ThreadDbKey));
+            JsonSerializer.SerializeToElement(this.ThreadDbKey);
 
         /// <summary>
         /// The data structure used to store chat history items in the vector store.

dotnet/samples/GettingStarted/Agents/Agent_Step13_Memory/Program.cs

@@ -52,7 +52,7 @@ Console.WriteLine(await agent.RunAsync("My name is Ruaidhrí", thread));
 Console.WriteLine(await agent.RunAsync("I am 20 years old", thread));
 
 // We can serialize the thread. The serialized state will include the state of the memory component.
-var threadElement = await thread.SerializeAsync();
+var threadElement = thread.Serialize();
 
 Console.WriteLine("\n>> Use deserialized thread with previously created memories\n");
 
@@ -148,9 +148,9 @@ namespace SampleApp
             });
         }
 
-        public override ValueTask<JsonElement?> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+        public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
         {
-            return new ValueTask<JsonElement?>(JsonSerializer.SerializeToElement(this.UserInfo, jsonSerializerOptions));
+            return JsonSerializer.SerializeToElement(this.UserInfo, jsonSerializerOptions);
         }
     }
 

dotnet/src/Microsoft.Agents.AI.Abstractions/AIContextProvider.cs

@@ -39,20 +39,15 @@ public abstract class AIContextProvider
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A task that completes when the context has been rendered and returned.</returns>
     public virtual ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
-    {
-        return default;
-    }
+        => default;
 
     /// <summary>
     /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
     /// </summary>
     /// <param name="jsonSerializerOptions">The JSON serialization options to use.</param>
-    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="JsonElement"/> representation of the object's state.</returns>
-    public virtual ValueTask<JsonElement?> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
-    {
-        return default;
-    }
+    public virtual JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
+        => default;
 
     /// <summary>Asks the <see cref="AIContextProvider"/> for an object of the specified type <paramref name="serviceType"/>.</summary>
     /// <param name="serviceType">The type of object being requested.</param>

dotnet/src/Microsoft.Agents.AI.Abstractions/AgentThread.cs

@@ -27,10 +27,9 @@ public abstract class AgentThread
     /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
     /// </summary>
     /// <param name="jsonSerializerOptions">The JSON serialization options to use.</param>
-    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="JsonElement"/> representation of the object's state.</returns>
-    public virtual Task<JsonElement> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
-        => Task.FromResult(default(JsonElement));
+    public virtual JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
+        => default;
 
     /// <summary>
     /// This method is called when new messages have been contributed to the chat by any participant.

dotnet/src/Microsoft.Agents.AI.Abstractions/ChatMessageStore.cs

@@ -51,9 +51,8 @@ public abstract class ChatMessageStore
     /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
     /// </summary>
     /// <param name="jsonSerializerOptions">The JSON serialization options to use.</param>
-    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="JsonElement"/> representation of the object's state.</returns>
-    public abstract ValueTask<JsonElement?> SerializeStateAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default);
+    public abstract JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null);
 
     /// <summary>Asks the <see cref="ChatMessageStore"/> for an object of the specified type <paramref name="serviceType"/>.</summary>
     /// <param name="serviceType">The type of object being requested.</param>

dotnet/src/Microsoft.Agents.AI.Abstractions/InMemoryAgentThread.cs

@@ -67,11 +67,10 @@ public abstract class InMemoryAgentThread : AgentThread
     /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
     /// </summary>
     /// <param name="jsonSerializerOptions">The JSON serialization options to use.</param>
-    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="JsonElement"/> representation of the object's state.</returns>
-    public override async Task<JsonElement> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+    public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
     {
-        var storeState = await this.MessageStore.SerializeStateAsync(jsonSerializerOptions, cancellationToken).ConfigureAwait(false);
+        var storeState = this.MessageStore.Serialize(jsonSerializerOptions);
 
         var state = new InMemoryAgentThreadState
         {

dotnet/src/Microsoft.Agents.AI.Abstractions/InMemoryChatMessageStore.cs

@@ -121,14 +121,14 @@ public sealed class InMemoryChatMessageStore : ChatMessageStore, IList<ChatMessa
     }
 
     /// <inheritdoc />
-    public override ValueTask<JsonElement?> SerializeStateAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+    public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
     {
         StoreState state = new()
         {
             Messages = this._messages,
         };
 
-        return new ValueTask<JsonElement?>(JsonSerializer.SerializeToElement(state, AgentAbstractionsJsonUtilities.DefaultOptions.GetTypeInfo(typeof(StoreState))));
+        return JsonSerializer.SerializeToElement(state, AgentAbstractionsJsonUtilities.DefaultOptions.GetTypeInfo(typeof(StoreState)));
     }
 
     /// <inheritdoc />

dotnet/src/Microsoft.Agents.AI.Abstractions/ServiceIdAgentThread.cs

@@ -2,8 +2,6 @@
 
 using System;
 using System.Text.Json;
-using System.Threading;
-using System.Threading.Tasks;
 using Microsoft.Shared.Diagnostics;
 
 namespace Microsoft.Agents.AI;
@@ -63,9 +61,8 @@ public abstract class ServiceIdAgentThread : AgentThread
     /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
     /// </summary>
     /// <param name="jsonSerializerOptions">The JSON serialization options to use.</param>
-    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A <see cref="JsonElement"/> representation of the object's state.</returns>
-    public override async Task<JsonElement> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+    public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
     {
         var state = new ServiceIdAgentThreadState
         {

dotnet/src/Microsoft.Agents.AI.Hosting/AgentActor.cs

@@ -121,7 +121,7 @@ internal sealed class AgentActor(
             }
 
             var serializedRunResponse = JsonSerializer.SerializeToElement(updates.ToAgentRunResponse(), AIJsonUtilities.DefaultOptions.GetTypeInfo(typeof(AgentRunResponse)));
-            var updatedThread = await this._thread.SerializeAsync(AgentHostingJsonUtilities.DefaultOptions, cancellationToken).ConfigureAwait(false);
+            var updatedThread = this._thread.Serialize(AgentHostingJsonUtilities.DefaultOptions);
 
             var writeResponse = await context.WriteAsync(
                 new(this._etag,

dotnet/src/Microsoft.Agents.AI/ChatClient/ChatClientAgentThread.cs

@@ -149,21 +149,16 @@ public class ChatClientAgentThread : AgentThread
     /// </summary>
     public AIContextProvider? AIContextProvider { get; internal set; }
 
-    /// <summary>
-    /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
-    /// </summary>
-    /// <param name="jsonSerializerOptions">The JSON serialization options to use.</param>
-    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
-    /// <returns>A <see cref="JsonElement"/> representation of the object's state.</returns>
-    public override async Task<JsonElement> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+    /// <inheritdoc/>
+    public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
     {
-        var storeState = this._messageStore is null ?
+        JsonElement? storeState = this._messageStore is null ?
             null :
-            await this._messageStore.SerializeStateAsync(jsonSerializerOptions, cancellationToken).ConfigureAwait(false);
+            this._messageStore.Serialize(jsonSerializerOptions);
 
-        var aiContextProviderState = this.AIContextProvider is null ?
+        JsonElement? aiContextProviderState = this.AIContextProvider is null ?
             null :
-            await this.AIContextProvider.SerializeAsync(jsonSerializerOptions, cancellationToken).ConfigureAwait(false);
+            this.AIContextProvider.Serialize(jsonSerializerOptions);
 
         var state = new ThreadState
         {

dotnet/src/Microsoft.Agents.Workflows/Specialized/AIAgentHostExecutor.cs

@@ -30,7 +30,7 @@ internal sealed class AIAgentHostExecutor : ChatProtocolExecutor
         Task threadTask = Task.CompletedTask;
         if (this._thread is not null)
         {
-            JsonElement threadValue = await this._thread.SerializeAsync(cancellationToken: cancellation).ConfigureAwait(false);
+            JsonElement threadValue = this._thread.Serialize();
             threadTask = context.QueueStateUpdateAsync(ThreadStateKey, threadValue).AsTask();
         }
 

dotnet/src/Microsoft.Agents.Workflows/WorkflowMessageStore.cs

@@ -65,7 +65,7 @@ internal sealed class WorkflowMessageStore : ChatMessageStore
 
     public void UpdateBookmark() => this._bookmark = this._chatMessages.Count;
 
-    public override ValueTask<JsonElement?> SerializeStateAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+    public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
     {
         StoreState state = new()
         {
@@ -73,8 +73,7 @@ internal sealed class WorkflowMessageStore : ChatMessageStore
             Messages = this._chatMessages,
         };
 
-        return new ValueTask<JsonElement?>
-            (JsonSerializer.SerializeToElement(state,
-            WorkflowsJsonUtilities.DefaultOptions.GetTypeInfo(typeof(StoreState))));
+        return JsonSerializer.SerializeToElement(state,
+            WorkflowsJsonUtilities.DefaultOptions.GetTypeInfo(typeof(StoreState)));
     }
 }

dotnet/src/Microsoft.Agents.Workflows/WorkflowThread.cs

@@ -2,8 +2,6 @@
 
 using System;
 using System.Text.Json;
-using System.Threading;
-using System.Threading.Tasks;
 using Microsoft.Agents.AI;
 using Microsoft.Extensions.AI;
 using Microsoft.Shared.Diagnostics;
@@ -28,7 +26,8 @@ internal sealed class WorkflowThread : AgentThread
 
     public string ResponseId => $"{this.RunId}@{this.Halts}";
 
-    public override Task<JsonElement> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default) => throw new NotImplementedException("Pending Checkpointing work.");
+    public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
+        => throw new NotImplementedException("Pending Checkpointing work.");
 
     public AgentRunResponseUpdate CreateUpdate(params AIContent[] parts)
     {

dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/AIContextProviderTests.cs

@@ -21,10 +21,10 @@ public class AIContextProviderTests
     }
 
     [Fact]
-    public async Task SerializeAsync_ReturnsEmptyElementAsync()
+    public void Serialize_ReturnsEmptyElement()
     {
         var provider = new TestAIContextProvider();
-        var actual = await provider.SerializeAsync();
+        var actual = provider.Serialize();
         Assert.Equal(default, actual);
     }
 
@@ -163,9 +163,9 @@ public class AIContextProviderTests
             return default;
         }
 
-        public override async ValueTask<JsonElement?> SerializeAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+        public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
         {
-            return await base.SerializeAsync(jsonSerializerOptions, cancellationToken);
+            return base.Serialize(jsonSerializerOptions);
         }
     }
 }

dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/AgentThreadTests.cs

@@ -2,7 +2,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Threading.Tasks;
 using Microsoft.Extensions.AI;
 
 #pragma warning disable CA1861 // Avoid constant arrays as arguments
@@ -15,10 +14,10 @@ namespace Microsoft.Agents.AI.Abstractions.UnitTests;
 public class AgentThreadTests
 {
     [Fact]
-    public async Task SerializeAsync_ReturnsDefaultJsonElementAsync()
+    public void Serialize_ReturnsDefaultJsonElement()
     {
         var thread = new TestAgentThread();
-        var result = await thread.SerializeAsync();
+        var result = thread.Serialize();
         Assert.Equal(default, result);
     }
 

dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/ChatMessageStoreTests.cs

@@ -84,7 +84,7 @@ public class ChatMessageStoreTests
         public override Task AddMessagesAsync(IEnumerable<ChatMessage> messages, CancellationToken cancellationToken = default)
             => Task.CompletedTask;
 
-        public override ValueTask<JsonElement?> SerializeStateAsync(JsonSerializerOptions? jsonSerializerOptions = null, CancellationToken cancellationToken = default)
+        public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
             => default;
     }
 }

dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/InMemoryAgentThreadTests.cs

@@ -4,7 +4,6 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text.Json;
-using System.Threading.Tasks;
 using Microsoft.Extensions.AI;
 
 namespace Microsoft.Agents.AI.Abstractions.UnitTests;
@@ -58,11 +57,11 @@ public class InMemoryAgentThreadTests
     }
 
     [Fact]
-    public async Task Constructor_WithSerializedState_SetsPropertyAsync()
+    public void Constructor_WithSerializedState_SetsProperty()
     {
         // Arrange
         InMemoryChatMessageStore store = [new(ChatRole.User, "TestMsg")];
-        var storeState = await store.SerializeStateAsync();
+        var storeState = store.Serialize();
         var json = JsonSerializer.SerializeToElement(new { storeState });
 
         // Act
@@ -89,13 +88,13 @@ public class InMemoryAgentThreadTests
     #region SerializeAsync Tests
 
     [Fact]
-    public async Task SerializeAsync_ReturnsCorrectJson_WhenMessagesExistAsync()
+    public void Serialize_ReturnsCorrectJson_WhenMessagesExist()
     {
         // Arrange
         var thread = new TestInMemoryAgentThread([new(ChatRole.User, "TestContent")]);
 
         // Act
-        var json = await thread.SerializeAsync();
+        var json = thread.Serialize();
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);
@@ -108,13 +107,13 @@ public class InMemoryAgentThreadTests
     }
 
     [Fact]
-    public async Task SerializeAsync_ReturnsEmptyMessages_WhenNoMessagesAsync()
+    public void Serialize_ReturnsEmptyMessages_WhenNoMessages()
     {
         // Arrange
         var thread = new TestInMemoryAgentThread();
 
         // Act
-        var json = await thread.SerializeAsync();
+        var json = thread.Serialize();
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);

dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/InMemoryChatMessageStoreTests.cs

@@ -106,8 +106,8 @@ public class InMemoryChatMessageStoreTests
             new ChatMessage(ChatRole.Assistant, "B")
         };
 
-        var jsonElement = await store.SerializeStateAsync();
-        var newStore = new InMemoryChatMessageStore(jsonElement.Value);
+        var jsonElement = store.Serialize();
+        var newStore = new InMemoryChatMessageStore(jsonElement);
 
         Assert.Equal(2, newStore.Count);
         Assert.Equal("A", newStore[0].Text);

dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/ServiceIdAgentThreadTests.cs

@@ -2,7 +2,6 @@
 
 using System;
 using System.Text.Json;
-using System.Threading.Tasks;
 
 namespace Microsoft.Agents.AI.Abstractions.UnitTests;
 
@@ -74,13 +73,13 @@ public class ServiceIdAgentThreadTests
     #region SerializeAsync Tests
 
     [Fact]
-    public async Task SerializeAsync_ReturnsCorrectJson_WhenServiceThreadIdIsSetAsync()
+    public void Serialize_ReturnsCorrectJson_WhenServiceThreadIdIsSet()
     {
         // Arrange
         var thread = new TestServiceIdAgentThread("service-id-789");
 
         // Act
-        var json = await thread.SerializeAsync();
+        var json = thread.Serialize();
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);
@@ -89,13 +88,13 @@ public class ServiceIdAgentThreadTests
     }
 
     [Fact]
-    public async Task SerializeAsync_ReturnsUndefinedServiceThreadId_WhenNotSetAsync()
+    public void Serialize_ReturnsUndefinedServiceThreadId_WhenNotSet()
     {
         // Arrange
         var thread = new TestServiceIdAgentThread();
 
         // Act
-        var json = await thread.SerializeAsync();
+        var json = thread.Serialize();
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);

dotnet/tests/Microsoft.Agents.AI.UnitTests/ChatClient/ChatClientAgentThreadTests.cs

@@ -216,13 +216,13 @@ public class ChatClientAgentThreadTests
     /// Verify thread serialization to JSON when the thread has an id.
     /// </summary>
     [Fact]
-    public async Task VerifyThreadSerializationWithIdAsync()
+    public void VerifyThreadSerializationWithId()
     {
         // Arrange
         var thread = new ChatClientAgentThread { ConversationId = "TestConvId" };
 
         // Act
-        var json = await thread.SerializeAsync();
+        var json = thread.Serialize();
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);
@@ -237,14 +237,14 @@ public class ChatClientAgentThreadTests
     /// Verify thread serialization to JSON when the thread has messages.
     /// </summary>
     [Fact]
-    public async Task VerifyThreadSerializationWithMessagesAsync()
+    public void VerifyThreadSerializationWithMessages()
     {
         // Arrange
         InMemoryChatMessageStore store = [new(ChatRole.User, "TestContent") { AuthorName = "TestAuthor" }];
         var thread = new ChatClientAgentThread { MessageStore = store };
 
         // Act
-        var json = await thread.SerializeAsync();
+        var json = thread.Serialize();
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);
@@ -269,14 +269,13 @@ public class ChatClientAgentThreadTests
     }
 
     [Fact]
-    public async Task VerifyThreadSerializationWithWithAIContextProviderAsync()
+    public void VerifyThreadSerializationWithWithAIContextProvider()
     {
         // Arrange
         Mock<AIContextProvider> mockProvider = new();
-        var providerStateElement = JsonSerializer.SerializeToElement(["CP1"], TestJsonSerializerContext.Default.StringArray);
         mockProvider
-            .Setup(m => m.SerializeAsync(It.IsAny<JsonSerializerOptions?>(), It.IsAny<CancellationToken>()))
-            .ReturnsAsync(providerStateElement);
+            .Setup(m => m.Serialize(It.IsAny<JsonSerializerOptions?>()))
+            .Returns(JsonSerializer.SerializeToElement(["CP1"], TestJsonSerializerContext.Default.StringArray));
 
         var thread = new ChatClientAgentThread
         {
@@ -284,7 +283,7 @@ public class ChatClientAgentThreadTests
         };
 
         // Act
-        var json = await thread.SerializeAsync();
+        var json = thread.Serialize();
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);
@@ -292,14 +291,14 @@ public class ChatClientAgentThreadTests
         Assert.Equal(JsonValueKind.Array, providerStateProperty.ValueKind);
         Assert.Single(providerStateProperty.EnumerateArray());
         Assert.Equal("CP1", providerStateProperty.EnumerateArray().First().GetString());
-        mockProvider.Verify(m => m.SerializeAsync(It.IsAny<JsonSerializerOptions?>(), It.IsAny<CancellationToken>()), Times.Once);
+        mockProvider.Verify(m => m.Serialize(It.IsAny<JsonSerializerOptions?>()), Times.Once);
     }
 
     /// <summary>
     /// Verify thread serialization to JSON with custom options.
     /// </summary>
     [Fact]
-    public async Task VerifyThreadSerializationWithCustomOptionsAsync()
+    public void VerifyThreadSerializationWithCustomOptions()
     {
         // Arrange
         var thread = new ChatClientAgentThread();
@@ -312,12 +311,12 @@ public class ChatClientAgentThreadTests
 
         var messageStoreMock = new Mock<ChatMessageStore>();
         messageStoreMock
-            .Setup(m => m.SerializeStateAsync(options, It.IsAny<CancellationToken>()))
-            .ReturnsAsync(storeStateElement);
+            .Setup(m => m.Serialize(options))
+            .Returns(storeStateElement);
         thread.MessageStore = messageStoreMock.Object;
 
         // Act
-        var json = await thread.SerializeAsync(options);
+        var json = thread.Serialize(options);
 
         // Assert
         Assert.Equal(JsonValueKind.Object, json.ValueKind);
@@ -330,7 +329,7 @@ public class ChatClientAgentThreadTests
         Assert.True(storeStateProperty.TryGetProperty("Key", out var keyProperty));
         Assert.Equal("TestValue", keyProperty.GetString());
 
-        messageStoreMock.Verify(m => m.SerializeStateAsync(options, It.IsAny<CancellationToken>()), Times.Once);
+        messageStoreMock.Verify(m => m.Serialize(options), Times.Once);
     }
 
     #endregion Serialize Tests