diff --git a/converters/sigma/src/ossie_sigma/sigma_to_ossie.py b/converters/sigma/src/ossie_sigma/sigma_to_ossie.py
index b108ebb6..b2fff4bf 100644
--- a/converters/sigma/src/ossie_sigma/sigma_to_ossie.py
+++ b/converters/sigma/src/ossie_sigma/sigma_to_ossie.py
@@ -458,9 +458,5 @@ def convert(self, spec: dict[str, Any]) -> ConverterResult[OssieDocument]:
             custom_extensions=[_vendor_ext(model_ext)] if model_ext else None,
         )
 
-        document = OssieDocument(
-            dialects=[OssieDialect.ANSI_SQL, OssieDialect.SIGMA],
-            vendors=[OssieVendor.SIGMA],
-            semantic_model=[semantic_model],
-        )
+        document = OssieDocument(semantic_model=[semantic_model])
         return ConverterResult(output=document, issues=issues)
diff --git a/core-spec/ossie-schema.json b/core-spec/ossie-schema.json
index 4e50f1ee..f20f0e92 100644
--- a/core-spec/ossie-schema.json
+++ b/core-spec/ossie-schema.json
@@ -16,20 +16,6 @@
       "items": {
         "$ref": "#/$defs/SemanticModel"
       }
-    },
-    "dialects": {
-      "type": "array",
-      "description": "Dialects used anywhere in this document",
-      "items": {
-        "$ref": "#/$defs/Dialect"
-      }
-    },
-    "vendors": {
-      "type": "array",
-      "description": "Vendors with custom_extensions present anywhere in this document",
-      "items": {
-        "$ref": "#/$defs/Vendor"
-      }
     }
   },
   "required": ["version", "semantic_model"],
diff --git a/validation/test_validate.py b/validation/test_validate.py
index 339396a4..156022a4 100644
--- a/validation/test_validate.py
+++ b/validation/test_validate.py
@@ -333,6 +333,23 @@ def test_valid_model_still_passes(self):
         self.assertEqual(result.returncode, 0)
         self.assertIn("Validation PASSED", result.stdout)
 
+    def test_root_dialects_and_vendors_are_rejected(self):
+        # The document root is version and semantic_model only; the dialect and
+        # vendor enumerations belong under expression.dialects and custom_extensions.
+        result = self.run_validator(
+            "version: 0.2.0.dev0\n"
+            "dialects: [ANSI_SQL]\n"
+            "vendors: [DBT]\n"
+            "semantic_model:\n"
+            "  - name: sales\n"
+            "    datasets:\n"
+            "      - name: orders\n"
+            "        source: analytics.orders\n"
+        )
+
+        self.assertEqual(result.returncode, 1)
+        self.assertIn("'dialects', 'vendors' were unexpected", result.stdout)
+
 
 if __name__ == "__main__":
     unittest.main()