diff --git a/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs b/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs
index 6745c6004..af3264fef 100644
--- a/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs
+++ b/src/modules/Elsa.Workflows.Core/Extensions/WorkflowExecutionContextExtensions.cs
@@ -14,7 +14,7 @@ public static class WorkflowExecutionContextExtensions
     /// <summary>
     /// Schedules the workflow for execution.
     /// </summary>
-    public static ActivityWorkItem ScheduleWorkflow(this WorkflowExecutionContext workflowExecutionContext, IDictionary<string, object>? input = default)
+    public static ActivityWorkItem ScheduleWorkflow(this WorkflowExecutionContext workflowExecutionContext, IDictionary<string, object>? input = null)
     {
         var workflow = workflowExecutionContext.Workflow;
         var workItem = new ActivityWorkItem(workflow, input: input);
@@ -25,7 +25,7 @@ public static class WorkflowExecutionContextExtensions
     /// <summary>
     /// Schedules the root activity of the workflow.
     /// </summary>
-    public static ActivityWorkItem ScheduleRoot(this WorkflowExecutionContext workflowExecutionContext, IDictionary<string, object>? input = default)
+    public static ActivityWorkItem ScheduleRoot(this WorkflowExecutionContext workflowExecutionContext, IDictionary<string, object>? input = null)
     {
         var workflow = workflowExecutionContext.Workflow;
         var workItem = new ActivityWorkItem(workflow.Root, input: input);
@@ -36,7 +36,7 @@ public static class WorkflowExecutionContextExtensions
     /// <summary>
     /// Schedules the specified activity of the workflow.
     /// </summary>
-    public static ActivityWorkItem ScheduleActivity(this WorkflowExecutionContext workflowExecutionContext, IActivity activity, IDictionary<string, object>? input = default)
+    public static ActivityWorkItem ScheduleActivity(this WorkflowExecutionContext workflowExecutionContext, IActivity activity, IDictionary<string, object>? input = null)
     {
         var workItem = new ActivityWorkItem(activity, input: input);
         workflowExecutionContext.Scheduler.Schedule(workItem);
@@ -46,7 +46,7 @@ public static class WorkflowExecutionContextExtensions
     /// <summary>
     /// Schedules the specified activity execution context of the workflow.
     /// </summary>
-    public static ActivityWorkItem ScheduleActivityExecutionContext(this WorkflowExecutionContext workflowExecutionContext, ActivityExecutionContext activityExecutionContext, IDictionary<string, object>? input = default)
+    public static ActivityWorkItem ScheduleActivityExecutionContext(this WorkflowExecutionContext workflowExecutionContext, ActivityExecutionContext activityExecutionContext, IDictionary<string, object>? input = null)
     {
         var workItem = new ActivityWorkItem(activityExecutionContext.Activity, input: input, existingActivityExecutionContext: activityExecutionContext);
         workflowExecutionContext.Scheduler.Schedule(workItem);
@@ -57,7 +57,7 @@ public static class WorkflowExecutionContextExtensions
     /// Schedules the activity of the specified bookmark.
     /// </summary>
     /// <returns>The created work item, or <c>null</c> if the specified bookmark doesn't exist in the <see cref="WorkflowExecutionContext"/></returns> 
-    public static ActivityWorkItem? ScheduleBookmark(this WorkflowExecutionContext workflowExecutionContext, Bookmark bookmark, IDictionary<string, object>? input = default)
+    public static ActivityWorkItem? ScheduleBookmark(this WorkflowExecutionContext workflowExecutionContext, Bookmark bookmark, IDictionary<string, object>? input = null)
     {
         // Get the activity execution context that owns the bookmark.
         var bookmarkedActivityContext = workflowExecutionContext.ActivityExecutionContexts.FirstOrDefault(x => x.Id == bookmark.ActivityInstanceId);
@@ -101,7 +101,7 @@ public static class WorkflowExecutionContextExtensions
         this WorkflowExecutionContext workflowExecutionContext,
         ActivityNode activityNode,
         ActivityExecutionContext owner,
-        ScheduleWorkOptions? options = default)
+        ScheduleWorkOptions? options = null)
     {
         // Validate that the specified activity is part of the workflow.
         if (!workflowExecutionContext.NodeActivityLookup.ContainsKey(activityNode.Activity))
diff --git a/src/modules/Elsa.Workflows.Core/Models/ActivityInput.cs b/src/modules/Elsa.Workflows.Core/Models/WorkflowInput.cs
similarity index 70%
rename from src/modules/Elsa.Workflows.Core/Models/ActivityInput.cs
rename to src/modules/Elsa.Workflows.Core/Models/WorkflowInput.cs
index a1bc13175..bdbb2e014 100644
--- a/src/modules/Elsa.Workflows.Core/Models/ActivityInput.cs
+++ b/src/modules/Elsa.Workflows.Core/Models/WorkflowInput.cs
@@ -1,6 +1,6 @@
 namespace Elsa.Workflows.Models;
 
 /// <summary>
-/// Represents an activity input name and value.
+/// Represents a workflow input name and value.
 /// </summary>
 public record WorkflowInput(string Name, object? Value);
\ No newline at end of file