diff --git a/src/modules/Elsa.Workflows.Core/Activities/Complete.cs b/src/modules/Elsa.Workflows.Core/Activities/Complete.cs
index 90ad5dd42..23b0c15bc 100644
--- a/src/modules/Elsa.Workflows.Core/Activities/Complete.cs
+++ b/src/modules/Elsa.Workflows.Core/Activities/Complete.cs
@@ -1,4 +1,5 @@
 using System.ComponentModel;
+using System.Text.Json.Serialization;
 using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Activities.Flowchart.Models;
 using Elsa.Workflows.Core.Attributes;
@@ -13,6 +14,12 @@ namespace Elsa.Workflows.Core.Activities;
 [Activity("Elsa", "Primitives", "Signals the current composite activity to complete itself as a whole.")]
 public class Complete : Activity
 {
+    /// <inheritdoc />
+    [JsonConstructor]
+    public Complete()
+    {
+    }
+    
     /// <inheritdoc />
     public Complete(params string[] outcomes) : this(new Input<ICollection<string>>(outcomes))
     {
@@ -35,7 +42,7 @@ public class Complete : Activity
     /// The outcome or set of outcomes to complete this activity with.
     /// </summary>
     [Description("The outcome or set of outcomes to complete this activity with.")]
-    public Input<ICollection<string>> Outcomes { get; set; }
+    public Input<ICollection<string>> Outcomes { get; set; } = new(new List<string>());
 
     /// <inheritdoc />
     protected override async ValueTask ExecuteAsync(ActivityExecutionContext context)