diff --git a/python/langsmith/client.py b/python/langsmith/client.py
index f683a36f1..40fa2c60f 100644
--- a/python/langsmith/client.py
+++ b/python/langsmith/client.py
@@ -1179,7 +1179,7 @@ def _run_transform(
             ):
                 # Drop completely
                 run_create.pop("serialized", None)
-            else:
+            elif run_create.get("serialized"):
                 # Drop graph
                 run_create["serialized"].pop("graph", None)