diff --git a/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowsJsonUtilities.cs b/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowsJsonUtilities.cs
index 6978cc1c93..c625cdfe32 100644
--- a/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowsJsonUtilities.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowsJsonUtilities.cs
@@ -7,6 +7,7 @@ using System.Text.Json.Serialization;
 using Microsoft.Agents.AI.Workflows.Checkpointing;
 using Microsoft.Agents.AI.Workflows.Execution;
 using Microsoft.Agents.AI.Workflows.Specialized;
+using Microsoft.Agents.AI.Workflows.Specialized.Magentic;
 using Microsoft.Extensions.AI;
 
 namespace Microsoft.Agents.AI.Workflows;
@@ -97,6 +98,9 @@ internal static partial class WorkflowsJsonUtilities
     [JsonSerializable(typeof(AIAgentHostState))]
     [JsonSerializable(typeof(HandoffSharedState))]
     [JsonSerializable(typeof(HandoffAgentHostState))]
+    [JsonSerializable(typeof(MagenticPlanReviewRequest))]
+    [JsonSerializable(typeof(MagenticPlanReviewResponse))]
+    [JsonSerializable(typeof(MagenticTaskState))]
 
     // Event Types
     //[JsonSerializable(typeof(WorkflowEvent))]