diff --git a/Directory.Packages.props b/Directory.Packages.props
index 5f7bf38..d3ba0c6 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -24,7 +24,7 @@
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />
     <PackageVersion Include="coverlet.collector" Version="8.0.1" />
     <PackageVersion Include="Moq" Version="4.20.72" />
-    <PackageVersion Include="ChromaDotNet.Testcontainers" Version="0.1.3" />
+    <PackageVersion Include="ChromaDotNet.Testcontainers" Version="0.1.7" />
     <PackageVersion Include="Microsoft.SemanticKernel.Core" Version="1.80.1" />
   </ItemGroup>
 
diff --git a/src/ChromaDB.VectorData/ChromaModelBuilder.cs b/src/ChromaDB.VectorData/ChromaModelBuilder.cs
index c74a5e3..1d8948a 100644
--- a/src/ChromaDB.VectorData/ChromaModelBuilder.cs
+++ b/src/ChromaDB.VectorData/ChromaModelBuilder.cs
@@ -30,6 +30,13 @@ protected override void ValidateKeyProperty(KeyPropertyModel keyProperty)
             throw new NotSupportedException(
                 $"Property '{keyProperty.ModelName}' has unsupported type '{type.Name}'. Key properties must be either string or Guid.");
         }
+
+        // String and Guid keys are supported by the Chroma provider, but we support auto-generation of keys only for GUIDs
+        if (keyProperty.IsAutoGenerated && keyProperty.Type != typeof(Guid))
+        {
+            throw new NotSupportedException(
+                $"Auto-generation is only supported for key properties of type Guid. Property '{keyProperty.ModelName}' has type '{keyProperty.Type.Name}'.");
+        }
     }
 
     // Checked when the collection object is constructed, rather than when it is first used.