diff --git a/prompts/csharp-mstest.prompt.md b/prompts/csharp-mstest.prompt.md
index 77d903a6..9a27bda8 100644
--- a/prompts/csharp-mstest.prompt.md
+++ b/prompts/csharp-mstest.prompt.md
@@ -166,10 +166,14 @@ Assert.IsNegative(number);
 ### Type Assertions
 
 ```csharp
-// Returns typed result for further assertions
+// MSTest 3.x - uses out parameter
 Assert.IsInstanceOfType<MyClass>(obj, out var typed);
 typed.DoSomething();
 
+// MSTest 4.x - returns typed result directly
+var typed = Assert.IsInstanceOfType<MyClass>(obj);
+typed.DoSomething();
+
 Assert.IsNotInstanceOfType<WrongType>(obj);
 ```