diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_Extension_Discovery.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_Extension_Discovery.verified.txt
index 74df5e37c6..2fc30a83fe 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_Extension_Discovery.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_Extension_Discovery.verified.txt
@@ -166,7 +166,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IRepository_string__GetById_M0_MockCall Callback(global::System.Action<int> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -236,7 +236,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IRepository_string__Save_M1_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Class_Type_Argument.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Class_Type_Argument.verified.txt
index e216d9570d..df55149d05 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Class_Type_Argument.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Class_Type_Argument.verified.txt
@@ -149,7 +149,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public Sandbox_IFoo_Sandbox_Bar__Process_M1_MockCall Callback(global::System.Action<global::Sandbox.Bar> callback)
         {
-            EnsureSetup().Callback(args => callback((global::Sandbox.Bar)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Multiple_Non_Builtin_Type_Arguments.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Multiple_Non_Builtin_Type_Arguments.verified.txt
index 2766fa1f4d..3f17e163f4 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Multiple_Non_Builtin_Type_Arguments.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Multiple_Non_Builtin_Type_Arguments.verified.txt
@@ -143,7 +143,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public Sandbox_IMapper_Sandbox_Entity_Sandbox_Status__Map_M0_MockCall Callback(global::System.Action<global::Sandbox.Entity> callback)
         {
-            EnsureSetup().Callback(args => callback((global::Sandbox.Entity)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Nested_Namespace_Type_Argument.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Nested_Namespace_Type_Argument.verified.txt
index 199200a7fd..1d1f0b1cee 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Nested_Namespace_Type_Argument.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Generic_Interface_With_Nested_Namespace_Type_Argument.verified.txt
@@ -149,7 +149,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public Sandbox_IService_Outer_Inner_Config__Apply_M1_MockCall Callback(global::System.Action<global::Outer.Inner.Config> callback)
         {
-            EnsureSetup().Callback(args => callback((global::Outer.Inner.Config)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_Inheriting_Multiple_Interfaces.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_Inheriting_Multiple_Interfaces.verified.txt
index 4804dd3118..2bcae59aa1 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_Inheriting_Multiple_Interfaces.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_Inheriting_Multiple_Interfaces.verified.txt
@@ -165,7 +165,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IReadWriter_Write_M2_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Async_Methods.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Async_Methods.verified.txt
index 5d526cb8d7..ee1bc297d7 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Async_Methods.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Async_Methods.verified.txt
@@ -260,7 +260,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IAsyncService_GetValueAsync_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -415,7 +415,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IAsyncService_ComputeAsync_M2_MockCall Callback(global::System.Action<int> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -492,7 +492,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IAsyncService_InitializeAsync_M3_MockCall Callback(global::System.Action<global::System.Threading.CancellationToken> callback)
         {
-            EnsureSetup().Callback(args => callback((global::System.Threading.CancellationToken)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Events.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Events.verified.txt
index c33be9fb39..ac17e57599 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Events.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Events.verified.txt
@@ -195,7 +195,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public INotifier_Notify_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Keyword_Parameter_Names.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Keyword_Parameter_Names.verified.txt
index edf7852f03..887078a01a 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Keyword_Parameter_Names.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Keyword_Parameter_Names.verified.txt
@@ -171,7 +171,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public ITest_Test_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -251,7 +251,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public ITest_Get_M1_MockCall Callback(global::System.Action<int, string> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!, (string)args[1]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Mixed_Members.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Mixed_Members.verified.txt
index 3929abc96c..9e5754d76c 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Mixed_Members.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Mixed_Members.verified.txt
@@ -274,7 +274,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IService_GetAsync_M3_MockCall Callback(global::System.Action<int> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -347,7 +347,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IService_Process_M4_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Nullable_Reference_Type_Parameters.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Nullable_Reference_Type_Parameters.verified.txt
index 7ec88b80ea..251905ed22 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Nullable_Reference_Type_Parameters.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Nullable_Reference_Type_Parameters.verified.txt
@@ -288,7 +288,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFoo_Bar_M0_MockCall Callback(global::System.Action<object?> callback)
         {
-            EnsureSetup().Callback(args => callback((object?)args[0]));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -368,7 +368,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFoo_GetValue_M1_MockCall Callback(global::System.Action<string?, int> callback)
         {
-            EnsureSetup().Callback(args => callback((string?)args[0], (int)args[1]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -438,7 +438,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFoo_Process_M2_MockCall Callback(global::System.Action<string, string?, object?> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!, (string?)args[1], (object?)args[2]));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -530,7 +530,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFoo_GetAsync_M3_MockCall Callback(global::System.Action<string?> callback)
         {
-            EnsureSetup().Callback(args => callback((string?)args[0]));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Out_Ref_Parameters.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Out_Ref_Parameters.verified.txt
index ad3c04e3d2..ac808c4c62 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Out_Ref_Parameters.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Out_Ref_Parameters.verified.txt
@@ -172,7 +172,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IDictionary_TryGetValue_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -245,7 +245,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IDictionary_Swap_M1_MockCall Callback(global::System.Action<int, int> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!, (int)args[1]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Overloaded_Methods.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Overloaded_Methods.verified.txt
index 60705ed74e..1fe1e22119 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Overloaded_Methods.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Overloaded_Methods.verified.txt
@@ -265,7 +265,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFormatter_Format_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -345,7 +345,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFormatter_Format_M1_MockCall Callback(global::System.Action<int> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -425,7 +425,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFormatter_Format_M2_MockCall Callback(global::System.Action<string, string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!, (string)args[1]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -505,7 +505,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IFormatter_Format_M3_MockCall Callback(global::System.Action<string, string, string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!, (string)args[1]!, (string)args[2]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Static_Abstract_Transitive_Return_Type.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Static_Abstract_Transitive_Return_Type.verified.txt
index f38f0b6214..42efb69368 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Static_Abstract_Transitive_Return_Type.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Interface_With_Static_Abstract_Transitive_Return_Type.verified.txt
@@ -162,7 +162,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IMyService_GetValue_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Multi_Method_Interface.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Multi_Method_Interface.verified.txt
index 1aed69f470..e5aa3f1404 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Multi_Method_Interface.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Multi_Method_Interface.verified.txt
@@ -209,7 +209,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public ICalculator_Add_M0_MockCall Callback(global::System.Action<int, int> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!, (int)args[1]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
@@ -289,7 +289,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public ICalculator_Subtract_M1_MockCall Callback(global::System.Action<int, int> callback)
         {
-            EnsureSetup().Callback(args => callback((int)args[0]!, (int)args[1]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Internal_Virtual_Members_From_External_Assembly.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Internal_Virtual_Members_From_External_Assembly.verified.txt
index 8221261294..d138493695 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Internal_Virtual_Members_From_External_Assembly.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Internal_Virtual_Members_From_External_Assembly.verified.txt
@@ -168,7 +168,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public ExternalLib_ExternalClient_PublicMethod_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Members_With_Internal_Signature_Types.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Members_With_Internal_Signature_Types.verified.txt
index fb6287604a..d9ee40cc69 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Members_With_Internal_Signature_Types.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Partial_Mock_Filters_Members_With_Internal_Signature_Types.verified.txt
@@ -128,7 +128,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public ExternalLib_ServiceClient_GetValue_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Simple_Interface_With_One_Method.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Simple_Interface_With_One_Method.verified.txt
index d8ba2a836a..8ee3000f09 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Simple_Interface_With_One_Method.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Simple_Interface_With_One_Method.verified.txt
@@ -143,7 +143,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public IGreeter_Greet_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Static_Extension_Discovery_Without_Mock_Of.verified.txt b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Static_Extension_Discovery_Without_Mock_Of.verified.txt
index 9da98fb638..f4b9505f3f 100644
--- a/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Static_Extension_Discovery_Without_Mock_Of.verified.txt
+++ b/TUnit.Mocks.SourceGenerator.Tests/Snapshots/Static_Extension_Discovery_Without_Mock_Of.verified.txt
@@ -149,7 +149,7 @@ namespace TUnit.Mocks.Generated
         /// <summary>Execute a typed callback using the actual method parameters.</summary>
         public INotifier_Notify_M0_MockCall Callback(global::System.Action<string> callback)
         {
-            EnsureSetup().Callback(args => callback((string)args[0]!));
+            EnsureSetup().Callback(callback);
             return this;
         }
 
diff --git a/TUnit.Mocks.SourceGenerator/Builders/MockMembersBuilder.cs b/TUnit.Mocks.SourceGenerator/Builders/MockMembersBuilder.cs
index cd378696e9..465a211023 100644
--- a/TUnit.Mocks.SourceGenerator/Builders/MockMembersBuilder.cs
+++ b/TUnit.Mocks.SourceGenerator/Builders/MockMembersBuilder.cs
@@ -432,12 +432,22 @@ private static void GenerateTypedCallbackOverload(CodeWriter writer, List<MockPa
     {
         var typeList = string.Join(", ", nonOutParams.Select(p => p.FullyQualifiedType));
         var actionType = $"global::System.Action<{typeList}>";
-        var castArgs = BuildCastArgs(nonOutParams, allNonOutParams);
 
         writer.AppendLine("/// <summary>Execute a typed callback using the actual method parameters.</summary>");
         using (writer.Block($"public {wrapperName} Callback({actionType} callback)"))
         {
-            writer.AppendLine($"EnsureSetup().Callback(args => callback({castArgs}));");
+            // allNonOutParams is null when this is the primary overload (no out/ref struct subset remapping).
+            // In that case the callback's parameter types match the typed Callback<T1,...> overload directly,
+            // so we can register it without a wrapping closure — avoiding the object?[] allocation.
+            if (allNonOutParams is null && nonOutParams.Count <= MaxTypedParams)
+            {
+                writer.AppendLine("EnsureSetup().Callback(callback);");
+            }
+            else
+            {
+                var castArgs = BuildCastArgs(nonOutParams, allNonOutParams);
+                writer.AppendLine($"EnsureSetup().Callback(args => callback({castArgs}));");
+            }
             writer.AppendLine("return this;");
         }
     }
diff --git a/TUnit.Mocks/MockEngine.Typed.cs b/TUnit.Mocks/MockEngine.Typed.cs
index b12307eac6..3e775fced5 100644
--- a/TUnit.Mocks/MockEngine.Typed.cs
+++ b/TUnit.Mocks/MockEngine.Typed.cs
@@ -3,11 +3,52 @@
 using TUnit.Mocks.Setup;
 using TUnit.Mocks.Setup.Behaviors;
 using System.ComponentModel;
+using System.Runtime.CompilerServices;
 
 namespace TUnit.Mocks;
 
 public sealed partial class MockEngine<T> where T : class
 {
+    // ── ARITY COUPLING (1–8) ──────────────────────────────────────────────
+    //  Behavior execution helpers — check IArgumentFreeBehavior, then
+    //  ITypedBehavior<T...>, then fall back to store.ToArray().
+    //  If you add an arity (e.g. T9), you MUST also update:
+    //    - ITypedBehavior<T1...T9> and TypedCallbackBehavior in TypedCallbackBehavior.cs
+    //    - Callback<T1...T9> in MethodSetupBuilder.cs and VoidMethodSetupBuilder.cs
+    //    - MaxTypedParams in MockMembersBuilder.cs (source generator)
+    // ──────────────────────────────────────────────────────────────────────
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1>(IBehavior b, in ArgumentStore<T1> store, T1 a1)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1> tb ? tb.Execute(a1) : b.Execute(store.ToArray());
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1, T2>(IBehavior b, in ArgumentStore<T1, T2> store, T1 a1, T2 a2)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1, T2> tb ? tb.Execute(a1, a2) : b.Execute(store.ToArray());
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1, T2, T3>(IBehavior b, in ArgumentStore<T1, T2, T3> store, T1 a1, T2 a2, T3 a3)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1, T2, T3> tb ? tb.Execute(a1, a2, a3) : b.Execute(store.ToArray());
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1, T2, T3, T4>(IBehavior b, in ArgumentStore<T1, T2, T3, T4> store, T1 a1, T2 a2, T3 a3, T4 a4)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1, T2, T3, T4> tb ? tb.Execute(a1, a2, a3, a4) : b.Execute(store.ToArray());
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1, T2, T3, T4, T5>(IBehavior b, in ArgumentStore<T1, T2, T3, T4, T5> store, T1 a1, T2 a2, T3 a3, T4 a4, T5 a5)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1, T2, T3, T4, T5> tb ? tb.Execute(a1, a2, a3, a4, a5) : b.Execute(store.ToArray());
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1, T2, T3, T4, T5, T6>(IBehavior b, in ArgumentStore<T1, T2, T3, T4, T5, T6> store, T1 a1, T2 a2, T3 a3, T4 a4, T5 a5, T6 a6)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1, T2, T3, T4, T5, T6> tb ? tb.Execute(a1, a2, a3, a4, a5, a6) : b.Execute(store.ToArray());
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1, T2, T3, T4, T5, T6, T7>(IBehavior b, in ArgumentStore<T1, T2, T3, T4, T5, T6, T7> store, T1 a1, T2 a2, T3 a3, T4 a4, T5 a5, T6 a6, T7 a7)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1, T2, T3, T4, T5, T6, T7> tb ? tb.Execute(a1, a2, a3, a4, a5, a6, a7) : b.Execute(store.ToArray());
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static object? ExecuteBehavior<T1, T2, T3, T4, T5, T6, T7, T8>(IBehavior b, in ArgumentStore<T1, T2, T3, T4, T5, T6, T7, T8> store, T1 a1, T2 a2, T3 a3, T4 a4, T5 a5, T6 a6, T7 a7, T8 a8)
+        => b is IArgumentFreeBehavior af ? af.Execute() : b is ITypedBehavior<T1, T2, T3, T4, T5, T6, T7, T8> tb ? tb.Execute(a1, a2, a3, a4, a5, a6, a7, a8) : b.Execute(store.ToArray());
     // ──────────────────────────────────────────────────────────────────────
     //  Arity 1
     // ──────────────────────────────────────────────────────────────────────
@@ -28,7 +69,7 @@ public void HandleCall<T1>(int memberId, string memberName, T1 arg1)
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -56,7 +97,7 @@ public TReturn HandleCallWithReturn<TReturn, T1>(int memberId, string memberName
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -120,7 +161,7 @@ public bool TryHandleCall<T1>(int memberId, string memberName, T1 arg1)
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -147,7 +188,7 @@ public bool TryHandleCallWithReturn<TReturn, T1>(int memberId, string memberName
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -186,7 +227,7 @@ public void HandleCall<T1, T2>(int memberId, string memberName, T1 arg1, T2 arg2
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -214,7 +255,7 @@ public TReturn HandleCallWithReturn<TReturn, T1, T2>(int memberId, string member
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1, arg2);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -278,7 +319,7 @@ public bool TryHandleCall<T1, T2>(int memberId, string memberName, T1 arg1, T2 a
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -305,7 +346,7 @@ public bool TryHandleCallWithReturn<TReturn, T1, T2>(int memberId, string member
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -344,7 +385,7 @@ public void HandleCall<T1, T2, T3>(int memberId, string memberName, T1 arg1, T2
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -372,7 +413,7 @@ public TReturn HandleCallWithReturn<TReturn, T1, T2, T3>(int memberId, string me
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1, arg2, arg3);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -436,7 +477,7 @@ public bool TryHandleCall<T1, T2, T3>(int memberId, string memberName, T1 arg1,
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -463,7 +504,7 @@ public bool TryHandleCallWithReturn<TReturn, T1, T2, T3>(int memberId, string me
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -502,7 +543,7 @@ public void HandleCall<T1, T2, T3, T4>(int memberId, string memberName, T1 arg1,
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -530,7 +571,7 @@ public TReturn HandleCallWithReturn<TReturn, T1, T2, T3, T4>(int memberId, strin
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -594,7 +635,7 @@ public bool TryHandleCall<T1, T2, T3, T4>(int memberId, string memberName, T1 ar
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -621,7 +662,7 @@ public bool TryHandleCallWithReturn<TReturn, T1, T2, T3, T4>(int memberId, strin
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -660,7 +701,7 @@ public void HandleCall<T1, T2, T3, T4, T5>(int memberId, string memberName, T1 a
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -688,7 +729,7 @@ public TReturn HandleCallWithReturn<TReturn, T1, T2, T3, T4, T5>(int memberId, s
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -752,7 +793,7 @@ public bool TryHandleCall<T1, T2, T3, T4, T5>(int memberId, string memberName, T
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -779,7 +820,7 @@ public bool TryHandleCallWithReturn<TReturn, T1, T2, T3, T4, T5>(int memberId, s
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -818,7 +859,7 @@ public void HandleCall<T1, T2, T3, T4, T5, T6>(int memberId, string memberName,
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -846,7 +887,7 @@ public TReturn HandleCallWithReturn<TReturn, T1, T2, T3, T4, T5, T6>(int memberI
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -910,7 +951,7 @@ public bool TryHandleCall<T1, T2, T3, T4, T5, T6>(int memberId, string memberNam
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -937,7 +978,7 @@ public bool TryHandleCallWithReturn<TReturn, T1, T2, T3, T4, T5, T6>(int memberI
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -976,7 +1017,7 @@ public void HandleCall<T1, T2, T3, T4, T5, T6, T7>(int memberId, string memberNa
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -1004,7 +1045,7 @@ public TReturn HandleCallWithReturn<TReturn, T1, T2, T3, T4, T5, T6, T7>(int mem
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -1068,7 +1109,7 @@ public bool TryHandleCall<T1, T2, T3, T4, T5, T6, T7>(int memberId, string membe
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -1095,7 +1136,7 @@ public bool TryHandleCallWithReturn<TReturn, T1, T2, T3, T4, T5, T6, T7>(int mem
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -1134,7 +1175,7 @@ public void HandleCall<T1, T2, T3, T4, T5, T6, T7, T8>(int memberId, string memb
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -1162,7 +1203,7 @@ public TReturn HandleCallWithReturn<TReturn, T1, T2, T3, T4, T5, T6, T7, T8>(int
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(store.ToArray());
+            var result = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
             if (result is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -1226,7 +1267,7 @@ public bool TryHandleCall<T1, T2, T3, T4, T5, T6, T7, T8>(int memberId, string m
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
@@ -1253,7 +1294,7 @@ public bool TryHandleCallWithReturn<TReturn, T1, T2, T3, T4, T5, T6, T7, T8>(int
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(store.ToArray());
+            var behaviorResult = ExecuteBehavior(behavior, store, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
             if (behaviorResult is RawReturn raw) RawReturnContext.Set(raw);
             try { ApplyMatchedSetup(matchedSetup); }
             catch { RawReturnContext.Clear(); throw; }
diff --git a/TUnit.Mocks/MockEngine.cs b/TUnit.Mocks/MockEngine.cs
index dae5f94c9c..54cee4b4ec 100644
--- a/TUnit.Mocks/MockEngine.cs
+++ b/TUnit.Mocks/MockEngine.cs
@@ -202,7 +202,7 @@ public void HandleCall(int memberId, string memberName, object?[] args)
 
         if (behavior is not null)
         {
-            var behaviorResult = behavior.Execute(args);
+            var behaviorResult = behavior is IArgumentFreeBehavior argFree ? argFree.Execute() : behavior.Execute(args);
             if (behaviorResult is RawReturn raw)
             {
                 RawReturnContext.Set(raw);
@@ -250,7 +250,7 @@ public TReturn HandleCallWithReturn<TReturn>(int memberId, string memberName, ob
 
         if (behavior is not null)
         {
-            var result = behavior.Execute(args);
+            var result = behavior is IArgumentFreeBehavior argFree ? argFree.Execute() : behavior.Execute(args);
             if (result is RawReturn raw)
             {
                 RawReturnContext.Set(raw);
diff --git a/TUnit.Mocks/Setup/Behaviors/CallbackBehavior.cs b/TUnit.Mocks/Setup/Behaviors/CallbackBehavior.cs
index 7cb7d63aa8..98ceac185e 100644
--- a/TUnit.Mocks/Setup/Behaviors/CallbackBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/CallbackBehavior.cs
@@ -1,12 +1,14 @@
 namespace TUnit.Mocks.Setup.Behaviors;
 
-internal sealed class CallbackBehavior : IBehavior
+internal sealed class CallbackBehavior : IBehavior, IArgumentFreeBehavior
 {
     private readonly Action _callback;
 
     public CallbackBehavior(Action callback) => _callback = callback;
 
-    public object? Execute(object?[] arguments)
+    public object? Execute(object?[] arguments) => Execute();
+
+    public object? Execute()
     {
         _callback();
         return null;
diff --git a/TUnit.Mocks/Setup/Behaviors/CallbackWithArgsBehavior.cs b/TUnit.Mocks/Setup/Behaviors/CallbackWithArgsBehavior.cs
index 3759656696..11ddd683c4 100644
--- a/TUnit.Mocks/Setup/Behaviors/CallbackWithArgsBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/CallbackWithArgsBehavior.cs
@@ -6,6 +6,9 @@ namespace TUnit.Mocks.Setup.Behaviors;
 /// Behavior that invokes a callback with the method arguments.
 /// Public for generated code access. Not intended for direct use.
 /// </summary>
+/// <remarks>
+/// Future optimization: implement ITypedBehavior&lt;T...&gt; to avoid store.ToArray() when args are needed.
+/// </remarks>
 [EditorBrowsable(EditorBrowsableState.Never)]
 public sealed class CallbackWithArgsBehavior : IBehavior
 {
diff --git a/TUnit.Mocks/Setup/Behaviors/ComputedReturnBehavior.cs b/TUnit.Mocks/Setup/Behaviors/ComputedReturnBehavior.cs
index a6faa10864..11d720d1db 100644
--- a/TUnit.Mocks/Setup/Behaviors/ComputedReturnBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/ComputedReturnBehavior.cs
@@ -1,10 +1,12 @@
 namespace TUnit.Mocks.Setup.Behaviors;
 
-internal sealed class ComputedReturnBehavior<TReturn> : IBehavior
+internal sealed class ComputedReturnBehavior<TReturn> : IBehavior, IArgumentFreeBehavior
 {
     private readonly Func<TReturn> _factory;
 
     public ComputedReturnBehavior(Func<TReturn> factory) => _factory = factory;
 
-    public object? Execute(object?[] arguments) => _factory();
+    public object? Execute(object?[] arguments) => Execute();
+
+    public object? Execute() => _factory();
 }
diff --git a/TUnit.Mocks/Setup/Behaviors/ComputedReturnWithArgsBehavior.cs b/TUnit.Mocks/Setup/Behaviors/ComputedReturnWithArgsBehavior.cs
index 2d7060a870..f306245e08 100644
--- a/TUnit.Mocks/Setup/Behaviors/ComputedReturnWithArgsBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/ComputedReturnWithArgsBehavior.cs
@@ -6,6 +6,9 @@ namespace TUnit.Mocks.Setup.Behaviors;
 /// Behavior that computes a return value from the method arguments.
 /// Public for generated code access. Not intended for direct use.
 /// </summary>
+/// <remarks>
+/// Future optimization: implement ITypedBehavior&lt;T...&gt; to avoid store.ToArray() when args are needed.
+/// </remarks>
 [EditorBrowsable(EditorBrowsableState.Never)]
 public sealed class ComputedReturnWithArgsBehavior<TReturn> : IBehavior
 {
diff --git a/TUnit.Mocks/Setup/Behaviors/ComputedThrowBehavior.cs b/TUnit.Mocks/Setup/Behaviors/ComputedThrowBehavior.cs
index beb4e6bba3..af0786b65a 100644
--- a/TUnit.Mocks/Setup/Behaviors/ComputedThrowBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/ComputedThrowBehavior.cs
@@ -6,6 +6,9 @@ namespace TUnit.Mocks.Setup.Behaviors;
 /// Behavior that computes an exception from the method arguments and throws it.
 /// Public for generated code access. Not intended for direct use.
 /// </summary>
+/// <remarks>
+/// Future optimization: implement ITypedBehavior&lt;T...&gt; to avoid store.ToArray() when args are needed.
+/// </remarks>
 [EditorBrowsable(EditorBrowsableState.Never)]
 public sealed class ComputedThrowBehavior : IBehavior
 {
diff --git a/TUnit.Mocks/Setup/Behaviors/IBehavior.cs b/TUnit.Mocks/Setup/Behaviors/IBehavior.cs
index 05914ef70e..15552d50f0 100644
--- a/TUnit.Mocks/Setup/Behaviors/IBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/IBehavior.cs
@@ -11,3 +11,15 @@ public interface IBehavior
 {
     object? Execute(object?[] arguments);
 }
+
+/// <summary>
+/// Marker interface for behaviors that do not use the method arguments.
+/// Implementing this avoids the allocation of the boxed argument array on the invocation hot path.
+/// Custom <see cref="IBehavior"/> implementations that ignore arguments can implement this
+/// to participate in the fast path.
+/// </summary>
+[EditorBrowsable(EditorBrowsableState.Never)]
+public interface IArgumentFreeBehavior
+{
+    object? Execute();
+}
diff --git a/TUnit.Mocks/Setup/Behaviors/RawReturnBehavior.cs b/TUnit.Mocks/Setup/Behaviors/RawReturnBehavior.cs
index a8fc4de305..cf8dba4ba6 100644
--- a/TUnit.Mocks/Setup/Behaviors/RawReturnBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/RawReturnBehavior.cs
@@ -1,23 +1,28 @@
 namespace TUnit.Mocks.Setup.Behaviors;
 
-internal sealed class RawReturnBehavior : IBehavior
+internal sealed class RawReturnBehavior : IBehavior, IArgumentFreeBehavior
 {
     private readonly RawReturn _wrapper;
 
     public RawReturnBehavior(object? rawValue) => _wrapper = new RawReturn(rawValue);
 
-    public object? Execute(object?[] arguments) => _wrapper;
+    public object? Execute(object?[] arguments) => Execute();
+
+    public object? Execute() => _wrapper;
 }
 
-internal sealed class ComputedRawReturnBehavior : IBehavior
+internal sealed class ComputedRawReturnBehavior : IBehavior, IArgumentFreeBehavior
 {
     private readonly Func<object?> _factory;
 
     public ComputedRawReturnBehavior(Func<object?> factory) => _factory = factory;
 
-    public object? Execute(object?[] arguments) => new RawReturn(_factory());
+    public object? Execute(object?[] arguments) => Execute();
+
+    public object? Execute() => new RawReturn(_factory());
 }
 
+// Future optimization: implement ITypedBehavior<T...> to avoid store.ToArray() when args are needed.
 internal sealed class ComputedRawReturnWithArgsBehavior : IBehavior
 {
     private readonly Func<object?[], object?> _factory;
diff --git a/TUnit.Mocks/Setup/Behaviors/ReturnBehavior.cs b/TUnit.Mocks/Setup/Behaviors/ReturnBehavior.cs
index f51371182c..7320546b21 100644
--- a/TUnit.Mocks/Setup/Behaviors/ReturnBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/ReturnBehavior.cs
@@ -1,10 +1,12 @@
 namespace TUnit.Mocks.Setup.Behaviors;
 
-internal sealed class ReturnBehavior<TReturn> : IBehavior
+internal sealed class ReturnBehavior<TReturn> : IBehavior, IArgumentFreeBehavior
 {
     private readonly TReturn _value;
 
     public ReturnBehavior(TReturn value) => _value = value;
 
-    public object? Execute(object?[] arguments) => _value;
+    public object? Execute(object?[] arguments) => Execute();
+
+    public object? Execute() => _value;
 }
diff --git a/TUnit.Mocks/Setup/Behaviors/ThrowBehavior.cs b/TUnit.Mocks/Setup/Behaviors/ThrowBehavior.cs
index b401dcddf4..bf5030f1e9 100644
--- a/TUnit.Mocks/Setup/Behaviors/ThrowBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/ThrowBehavior.cs
@@ -1,10 +1,12 @@
 namespace TUnit.Mocks.Setup.Behaviors;
 
-internal sealed class ThrowBehavior : IBehavior
+internal sealed class ThrowBehavior : IBehavior, IArgumentFreeBehavior
 {
     private readonly Exception _exception;
 
     public ThrowBehavior(Exception exception) => _exception = exception;
 
-    public object? Execute(object?[] arguments) => throw _exception;
+    public object? Execute(object?[] arguments) => Execute();
+
+    public object? Execute() => throw _exception;
 }
diff --git a/TUnit.Mocks/Setup/Behaviors/TypedCallbackBehavior.cs b/TUnit.Mocks/Setup/Behaviors/TypedCallbackBehavior.cs
new file mode 100644
index 0000000000..e09c54e759
--- /dev/null
+++ b/TUnit.Mocks/Setup/Behaviors/TypedCallbackBehavior.cs
@@ -0,0 +1,156 @@
+namespace TUnit.Mocks.Setup.Behaviors;
+
+/// <summary>
+/// Typed behavior dispatch interfaces. ExecuteBehavior checks for these after IArgumentFreeBehavior,
+/// enabling behaviors to receive typed arguments without boxing into object?[].
+/// Currently implemented by TypedCallbackBehavior; extensible for future typed return behaviors
+/// (e.g. a TypedComputedReturnBehavior that takes Func&lt;T1, TReturn&gt;).
+/// </summary>
+/// <remarks>
+/// Intentionally internal: the typed dispatch is tightly coupled to the source generator's
+/// knowledge of parameter arity — only generated code knows the concrete types at compile time.
+/// <see cref="IArgumentFreeBehavior"/> is public because any behavior can opt in without type knowledge.
+/// </remarks>
+internal interface ITypedBehavior<T1>
+{
+    object? Execute(T1 arg1);
+}
+
+internal interface ITypedBehavior<T1, T2>
+{
+    object? Execute(T1 arg1, T2 arg2);
+}
+
+internal interface ITypedBehavior<T1, T2, T3>
+{
+    object? Execute(T1 arg1, T2 arg2, T3 arg3);
+}
+
+internal interface ITypedBehavior<T1, T2, T3, T4>
+{
+    object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4);
+}
+
+internal interface ITypedBehavior<T1, T2, T3, T4, T5>
+{
+    object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5);
+}
+
+internal interface ITypedBehavior<T1, T2, T3, T4, T5, T6>
+{
+    object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6);
+}
+
+internal interface ITypedBehavior<T1, T2, T3, T4, T5, T6, T7>
+{
+    object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7);
+}
+
+internal interface ITypedBehavior<T1, T2, T3, T4, T5, T6, T7, T8>
+{
+    object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7, T8 arg8);
+}
+
+// ── ARITY COUPLING (1–8) ──────────────────────────────────────────────
+// If you add an arity (e.g. T9), you MUST also update:
+//   - ITypedBehavior<T1...T9> above
+//   - ExecuteBehavior<T1...T9> in MockEngine.Typed.cs
+//   - Callback<T1...T9> in MethodSetupBuilder.cs and VoidMethodSetupBuilder.cs
+//   - MaxTypedParams in MockMembersBuilder.cs (source generator)
+// ──────────────────────────────────────────────────────────────────────
+
+internal sealed class TypedCallbackBehavior<T1>(Action<T1> callback) : IBehavior, ITypedBehavior<T1>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 1) throw new ArgumentException($"Expected at least 1 argument, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1) { callback(arg1); return null; }
+}
+
+internal sealed class TypedCallbackBehavior<T1, T2>(Action<T1, T2> callback) : IBehavior, ITypedBehavior<T1, T2>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 2) throw new ArgumentException($"Expected at least 2 arguments, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!, (T2)arguments[1]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1, T2 arg2) { callback(arg1, arg2); return null; }
+}
+
+internal sealed class TypedCallbackBehavior<T1, T2, T3>(Action<T1, T2, T3> callback) : IBehavior, ITypedBehavior<T1, T2, T3>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 3) throw new ArgumentException($"Expected at least 3 arguments, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!, (T2)arguments[1]!, (T3)arguments[2]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1, T2 arg2, T3 arg3) { callback(arg1, arg2, arg3); return null; }
+}
+
+internal sealed class TypedCallbackBehavior<T1, T2, T3, T4>(Action<T1, T2, T3, T4> callback) : IBehavior, ITypedBehavior<T1, T2, T3, T4>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 4) throw new ArgumentException($"Expected at least 4 arguments, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!, (T2)arguments[1]!, (T3)arguments[2]!, (T4)arguments[3]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4) { callback(arg1, arg2, arg3, arg4); return null; }
+}
+
+internal sealed class TypedCallbackBehavior<T1, T2, T3, T4, T5>(Action<T1, T2, T3, T4, T5> callback) : IBehavior, ITypedBehavior<T1, T2, T3, T4, T5>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 5) throw new ArgumentException($"Expected at least 5 arguments, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!, (T2)arguments[1]!, (T3)arguments[2]!, (T4)arguments[3]!, (T5)arguments[4]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5) { callback(arg1, arg2, arg3, arg4, arg5); return null; }
+}
+
+internal sealed class TypedCallbackBehavior<T1, T2, T3, T4, T5, T6>(Action<T1, T2, T3, T4, T5, T6> callback) : IBehavior, ITypedBehavior<T1, T2, T3, T4, T5, T6>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 6) throw new ArgumentException($"Expected at least 6 arguments, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!, (T2)arguments[1]!, (T3)arguments[2]!, (T4)arguments[3]!, (T5)arguments[4]!, (T6)arguments[5]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6) { callback(arg1, arg2, arg3, arg4, arg5, arg6); return null; }
+}
+
+internal sealed class TypedCallbackBehavior<T1, T2, T3, T4, T5, T6, T7>(Action<T1, T2, T3, T4, T5, T6, T7> callback) : IBehavior, ITypedBehavior<T1, T2, T3, T4, T5, T6, T7>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 7) throw new ArgumentException($"Expected at least 7 arguments, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!, (T2)arguments[1]!, (T3)arguments[2]!, (T4)arguments[3]!, (T5)arguments[4]!, (T6)arguments[5]!, (T7)arguments[6]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7) { callback(arg1, arg2, arg3, arg4, arg5, arg6, arg7); return null; }
+}
+
+internal sealed class TypedCallbackBehavior<T1, T2, T3, T4, T5, T6, T7, T8>(Action<T1, T2, T3, T4, T5, T6, T7, T8> callback) : IBehavior, ITypedBehavior<T1, T2, T3, T4, T5, T6, T7, T8>
+{
+    public object? Execute(object?[] arguments)
+    {
+        if (arguments.Length < 8) throw new ArgumentException($"Expected at least 8 arguments, got {arguments.Length}.", nameof(arguments));
+        callback((T1)arguments[0]!, (T2)arguments[1]!, (T3)arguments[2]!, (T4)arguments[3]!, (T5)arguments[4]!, (T6)arguments[5]!, (T7)arguments[6]!, (T8)arguments[7]!);
+        return null;
+    }
+
+    public object? Execute(T1 arg1, T2 arg2, T3 arg3, T4 arg4, T5 arg5, T6 arg6, T7 arg7, T8 arg8) { callback(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8); return null; }
+}
diff --git a/TUnit.Mocks/Setup/Behaviors/VoidReturnBehavior.cs b/TUnit.Mocks/Setup/Behaviors/VoidReturnBehavior.cs
index f97398055d..d9bee1200c 100644
--- a/TUnit.Mocks/Setup/Behaviors/VoidReturnBehavior.cs
+++ b/TUnit.Mocks/Setup/Behaviors/VoidReturnBehavior.cs
@@ -1,8 +1,10 @@
 namespace TUnit.Mocks.Setup.Behaviors;
 
-internal sealed class VoidReturnBehavior : IBehavior
+internal sealed class VoidReturnBehavior : IBehavior, IArgumentFreeBehavior
 {
     public static VoidReturnBehavior Instance { get; } = new();
 
-    public object? Execute(object?[] arguments) => null;
+    public object? Execute(object?[] arguments) => Execute();
+
+    public object? Execute() => null;
 }
diff --git a/TUnit.Mocks/Setup/MethodSetupBuilder.cs b/TUnit.Mocks/Setup/MethodSetupBuilder.cs
index c81a4d1145..17fe4bb4ab 100644
--- a/TUnit.Mocks/Setup/MethodSetupBuilder.cs
+++ b/TUnit.Mocks/Setup/MethodSetupBuilder.cs
@@ -64,6 +64,66 @@ public ISetupChain<TReturn> Callback(Action<object?[]> callback)
         return this;
     }
 
+    // ── ARITY COUPLING (1–8): keep in sync with VoidMethodSetupBuilder,
+    //    TypedCallbackBehavior.cs, MockEngine.Typed.cs, and MaxTypedParams in MockMembersBuilder.cs
+
+    /// <summary>Typed callback overload emitted by the source generator. Avoids boxing arguments into object?[].</summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1>(Action<T1> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1, T2>(Action<T1, T2> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1, T2, T3>(Action<T1, T2, T3> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1, T2, T3, T4>(Action<T1, T2, T3, T4> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1, T2, T3, T4, T5>(Action<T1, T2, T3, T4, T5> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1, T2, T3, T4, T5, T6>(Action<T1, T2, T3, T4, T5, T6> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5, T6>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1, T2, T3, T4, T5, T6, T7>(Action<T1, T2, T3, T4, T5, T6, T7> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5, T6, T7>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public ISetupChain<TReturn> Callback<T1, T2, T3, T4, T5, T6, T7, T8>(Action<T1, T2, T3, T4, T5, T6, T7, T8> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5, T6, T7, T8>(callback));
+        return this;
+    }
+
     [EditorBrowsable(EditorBrowsableState.Never)]
     public ISetupChain<TReturn> Returns(Func<object?[], TReturn> factory)
     {
diff --git a/TUnit.Mocks/Setup/VoidMethodSetupBuilder.cs b/TUnit.Mocks/Setup/VoidMethodSetupBuilder.cs
index cf602bed48..05ddc34169 100644
--- a/TUnit.Mocks/Setup/VoidMethodSetupBuilder.cs
+++ b/TUnit.Mocks/Setup/VoidMethodSetupBuilder.cs
@@ -48,6 +48,66 @@ public IVoidSetupChain Callback(Action<object?[]> callback)
         return this;
     }
 
+    // ── ARITY COUPLING (1–8): keep in sync with MethodSetupBuilder,
+    //    TypedCallbackBehavior.cs, MockEngine.Typed.cs, and MaxTypedParams in MockMembersBuilder.cs
+
+    /// <summary>Typed callback overload emitted by the source generator. Avoids boxing arguments into object?[].</summary>
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1>(Action<T1> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1, T2>(Action<T1, T2> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1, T2, T3>(Action<T1, T2, T3> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1, T2, T3, T4>(Action<T1, T2, T3, T4> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1, T2, T3, T4, T5>(Action<T1, T2, T3, T4, T5> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1, T2, T3, T4, T5, T6>(Action<T1, T2, T3, T4, T5, T6> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5, T6>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1, T2, T3, T4, T5, T6, T7>(Action<T1, T2, T3, T4, T5, T6, T7> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5, T6, T7>(callback));
+        return this;
+    }
+
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    public IVoidSetupChain Callback<T1, T2, T3, T4, T5, T6, T7, T8>(Action<T1, T2, T3, T4, T5, T6, T7, T8> callback)
+    {
+        _setup.AddBehavior(new TypedCallbackBehavior<T1, T2, T3, T4, T5, T6, T7, T8>(callback));
+        return this;
+    }
+
     [EditorBrowsable(EditorBrowsableState.Never)]
     public IVoidSetupChain Throws(Func<object?[], Exception> exceptionFactory)
     {