diff --git a/src/libs/AutoSDK/Models/TypeData.cs b/src/libs/AutoSDK/Models/TypeData.cs
index c4658f607e..ce104a4218 100644
--- a/src/libs/AutoSDK/Models/TypeData.cs
+++ b/src/libs/AutoSDK/Models/TypeData.cs
@@ -146,8 +146,10 @@ Default with
                 .ToImmutableArray();
         }
         
+        var type = GetCSharpType(context);
+        
         return new TypeData(
-            CSharpType: GetCSharpType(context),
+            CSharpType: type,
             IsValueType: ContextIsValueType(context),
             IsArray: context.Schema.IsArray(),
             IsEnum: context.Schema.IsEnum(),
@@ -169,7 +171,9 @@ Default with
             Properties: properties,
             EnumValues: enumValues,
             SubTypes: subTypes,
-            Namespace: context.Settings.Namespace,
+            Namespace: type.StartsWith("global::System.", StringComparison.Ordinal)
+                ? "System"
+                : context.Settings.Namespace,
             IsDeprecated: context.Schema.Deprecated,
             JsonSerializerType: context.Settings.JsonSerializerType,
             GenerateJsonSerializerContextTypes: context.Settings.GenerateJsonSerializerContextTypes);
diff --git a/src/tests/AutoSDK.UnitTests/JsonTests.JsonSerializerContextTypes.cs b/src/tests/AutoSDK.UnitTests/JsonTests.JsonSerializerContextTypes.cs
index e1a407dfe2..8819741bfc 100644
--- a/src/tests/AutoSDK.UnitTests/JsonTests.JsonSerializerContextTypes.cs
+++ b/src/tests/AutoSDK.UnitTests/JsonTests.JsonSerializerContextTypes.cs
@@ -45,6 +45,18 @@ TypeData.Default with
             ],
         }, makeNullableRootIfValueType: true).Should().Be("IListIListString");
         
+        GetContextType(TypeData.Default with
+        {
+            Namespace = "System.Collections.Generic",
+            CSharpType = "global::System.Collections.Generic.IList<global::System.Guid>",
+            IsArray = true,
+            SubTypes = [
+                TypeData.Default with { 
+                    Namespace = "System",
+                    CSharpType = "global::System.Guid" }
+            ],
+        }, makeNullableRootIfValueType: true).Should().Be("IListGuid");
+
         GetContextType(TypeData.Default with
         {
             CSharpType = "byte[]",
@@ -88,9 +100,9 @@ TypeData.Default with
         
         GetContextType(TypeData.Default with
         {
-            Namespace = "System",
+            Namespace = "G",
             IsValueType = true,
-            CSharpType = "global::System.AllOf<Integration?, AppsCreateFromManifestResponse>",
+            CSharpType = "global::G.AllOf<Integration?, AppsCreateFromManifestResponse>",
             SubTypes = [
                 TypeData.Default with
                 {
@@ -105,9 +117,9 @@ TypeData.Default with
         
         GetContextType(TypeData.Default with
         {
-            Namespace = "System",
+            Namespace = "Cohere",
             IsValueType = true,
-            CSharpType = "global::System.OneOf<global::Cohere.NonStreamedChatResponse, global::Cohere.StreamedChatResponse?>",
+            CSharpType = "global::Cohere.OneOf<global::Cohere.NonStreamedChatResponse, global::Cohere.StreamedChatResponse?>",
             SubTypes = [
                 TypeData.Default with
                 {