diff --git a/databroker/mongo_normalized.py b/databroker/mongo_normalized.py
index 50af5f3f3..1681be0c8 100644
--- a/databroker/mongo_normalized.py
+++ b/databroker/mongo_normalized.py
@@ -474,6 +474,10 @@ async def update_metadata(self, metadata=None, specs=None):
              raise NotImplementedError('Update_metadata method requires descriptors.')
         # Update descriptors
         for descriptor in metadata["descriptors"]:
+            try:
+                schema_validators[DocumentNames.descriptor].validate(descriptor)
+            except ValidationError as err:
+                raise
             self.serializer.update("descriptor", descriptor)