diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CacheControlDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CacheControlDirectiveMerger.cs
index fb46239d660..80db2e11cbf 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CacheControlDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CacheControlDirectiveMerger.cs
@@ -20,7 +20,7 @@ mergeBehavior is DirectiveMergeBehavior.IncludePrivate
             ? $"fusion__{DirectiveNames.CacheControl}"
             : DirectiveNames.CacheControl;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
         return CacheControlMutableDirectiveDefinition.Create(schema);
     }
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CostDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CostDirectiveMerger.cs
index 1e5d18547d9..5a398450fcd 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CostDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/CostDirectiveMerger.cs
@@ -17,7 +17,7 @@ internal class CostDirectiveMerger(DirectiveMergeBehavior mergeBehavior)
 {
     public override string DirectiveName => DirectiveNames.Cost;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
         return CostMutableDirectiveDefinition.Create(schema);
     }
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/DirectiveMergerBase.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/DirectiveMergerBase.cs
index 9b30383532c..0d5a738087b 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/DirectiveMergerBase.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/DirectiveMergerBase.cs
@@ -12,7 +12,7 @@ internal abstract class DirectiveMergerBase(DirectiveMergeBehavior mergeBehavior
 
     public DirectiveMergeBehavior MergeBehavior { get; } = mergeBehavior;
 
-    public abstract MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema);
+    public abstract MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema);
 
     public virtual void MergeDirectiveDefinition(
         MutableDirectiveDefinition directiveDefinition,
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/IDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/IDirectiveMerger.cs
index dbfe4706063..d95e24df45d 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/IDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/IDirectiveMerger.cs
@@ -12,7 +12,7 @@ internal interface IDirectiveMerger
 
     DirectiveMergeBehavior MergeBehavior { get; }
 
-    MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema);
+    MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema);
 
     void MergeDirectiveDefinition(
         MutableDirectiveDefinition directiveDefinition,
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/ListSizeDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/ListSizeDirectiveMerger.cs
index a66b645db55..14f9f52e730 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/ListSizeDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/ListSizeDirectiveMerger.cs
@@ -17,7 +17,7 @@ internal class ListSizeDirectiveMerger(DirectiveMergeBehavior mergeBehavior)
 {
     public override string DirectiveName => DirectiveNames.ListSize;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
         return ListSizeMutableDirectiveDefinition.Create(schema);
     }
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/McpToolAnnotationsDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/McpToolAnnotationsDirectiveMerger.cs
index 07553fb38d5..e137db9e74e 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/McpToolAnnotationsDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/McpToolAnnotationsDirectiveMerger.cs
@@ -16,7 +16,7 @@ internal class McpToolAnnotationsDirectiveMerger(DirectiveMergeBehavior mergeBeh
 {
     public override string DirectiveName => DirectiveNames.McpToolAnnotations;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
         return McpToolAnnotationsMutableDirectiveDefinition.Create(schema);
     }
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/OneOfDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/OneOfDirectiveMerger.cs
index 96a59a01934..becdffd8e4a 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/OneOfDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/OneOfDirectiveMerger.cs
@@ -13,9 +13,9 @@ internal class OneOfDirectiveMerger(DirectiveMergeBehavior mergeBehavior)
 {
     public override string DirectiveName => DirectiveNames.OneOf;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
-        return OneOfMutableDirectiveDefinition.Create(schema);
+        return BuiltIns.OneOf.Create();
     }
 
     public override void MergeDirectives(
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SerializeAsDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SerializeAsDirectiveMerger.cs
index 925b994fd8d..1d4259a924e 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SerializeAsDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SerializeAsDirectiveMerger.cs
@@ -18,7 +18,7 @@ internal class SerializeAsDirectiveMerger(DirectiveMergeBehavior mergeBehavior)
 {
     public override string DirectiveName => DirectiveNames.SerializeAs;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
         return SerializeAsMutableDirectiveDefinition.Create(schema);
     }
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SpecifiedByDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SpecifiedByDirectiveMerger.cs
index 0b40a2ea217..1558c339637 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SpecifiedByDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/SpecifiedByDirectiveMerger.cs
@@ -15,9 +15,9 @@ internal class SpecifiedByDirectiveMerger(DirectiveMergeBehavior mergeBehavior)
 {
     public override string DirectiveName => DirectiveNames.SpecifiedBy;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
-        return SpecifiedByMutableDirectiveDefinition.Create(schema);
+        return BuiltIns.SpecifiedBy.Create(schema);
     }
 
     public override void MergeDirectives(
diff --git a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/TagDirectiveMerger.cs b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/TagDirectiveMerger.cs
index ceabb99788f..638ca0d178b 100644
--- a/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/TagDirectiveMerger.cs
+++ b/src/HotChocolate/Fusion-vnext/src/Fusion.Composition/DirectiveMergers/TagDirectiveMerger.cs
@@ -19,7 +19,7 @@ mergeBehavior is DirectiveMergeBehavior.IncludePrivate
             ? $"fusion__{DirectiveNames.Tag}"
             : DirectiveNames.Tag;
 
-    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(ISchemaDefinition schema)
+    public override MutableDirectiveDefinition GetCanonicalDirectiveDefinition(MutableSchemaDefinition schema)
     {
         return TagMutableDirectiveDefinition.Create(schema);
     }
diff --git a/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/OneOfMutableDirectiveDefinition.cs b/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/OneOfMutableDirectiveDefinition.cs
index 372243defcc..61c839b2796 100644
--- a/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/OneOfMutableDirectiveDefinition.cs
+++ b/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/OneOfMutableDirectiveDefinition.cs
@@ -8,9 +8,4 @@ internal OneOfMutableDirectiveDefinition()
         IsSpecDirective = true;
         Locations = DirectiveLocation.InputObject;
     }
-
-    public static OneOfMutableDirectiveDefinition Create(ISchemaDefinition _)
-    {
-        return new OneOfMutableDirectiveDefinition();
-    }
 }
diff --git a/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/SpecifiedByMutableDirectiveDefinition.cs b/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/SpecifiedByMutableDirectiveDefinition.cs
index eb605c7ade2..43d18da391f 100644
--- a/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/SpecifiedByMutableDirectiveDefinition.cs
+++ b/src/HotChocolate/Mutable/src/Types.Mutable/BuiltIns/SpecifiedByMutableDirectiveDefinition.cs
@@ -11,16 +11,4 @@ internal SpecifiedByMutableDirectiveDefinition(MutableScalarTypeDefinition strin
     }
 
     public MutableInputFieldDefinition Url => Arguments[DirectiveNames.SpecifiedBy.Arguments.Url];
-
-    public static SpecifiedByMutableDirectiveDefinition Create(ISchemaDefinition schema)
-    {
-        if (!schema.Types.TryGetType<MutableScalarTypeDefinition>(
-            SpecScalarNames.String.Name,
-            out var stringType))
-        {
-            stringType = BuiltIns.String.Create();
-        }
-
-        return new SpecifiedByMutableDirectiveDefinition(stringType);
-    }
 }