diff --git a/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyContext.cs b/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyContext.cs
index abce6e9..8ea0f89 100644
--- a/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyContext.cs
+++ b/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyContext.cs
@@ -138,7 +138,7 @@ public Router Router
 
         public ICommandPublisher Publisher => Router;
 
-        public MRubyCommandPreset CommandPreset { get; set; } = default!;
+        public MRubyCommandPreset? CommandPreset { get; set; }
 
         public override bool IsInvalid => handle == IntPtr.Zero;
         Router? router;
diff --git a/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyScript.cs b/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyScript.cs
index 0fb9c6f..388394c 100644
--- a/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyScript.cs
+++ b/src/VitalRouter.Unity/Assets/VitalRouter.MRuby/Runtime/MRubyScript.cs
@@ -225,7 +225,7 @@ internal static unsafe void OnCommandCalled(int scriptId, MrbNString commandName
                     {
                         return;
                     }
-                    _ = script.Context.CommandPreset.CommandCallFromMrubyAsync(script, fixedCommandName, payload);
+                    _ = script.Context.CommandPreset?.CommandCallFromMrubyAsync(script, fixedCommandName, payload);
                 }
                 catch (Exception ex)
                 {