diff --git a/crunch/cli.py b/crunch/cli.py
index ca69a70..7fd8e71 100644
--- a/crunch/cli.py
+++ b/crunch/cli.py
@@ -858,8 +858,8 @@ def cloud_executor(
         gpu,
         # ---
         api.ColumnNames(
-            id_column_name,
-            moon_column_name,
+            id_column_name or None,
+            moon_column_name or None,
             side_column_name or None,
             input_column_name or None,
             output_column_name or None,
diff --git a/crunch/runner/cloud.py b/crunch/runner/cloud.py
index 24b3bae..d2d3165 100644
--- a/crunch/runner/cloud.py
+++ b/crunch/runner/cloud.py
@@ -656,8 +656,8 @@ def sandbox(
                 "number-of-features": self.number_of_features,
                 "gpu": self.gpu,
                 # ---
-                "id-column-name": self.column_names.id,
-                "moon-column-name": self.column_names.moon,
+                "id-column-name": self.column_names.id or "",
+                "moon-column-name": self.column_names.moon or "",
                 "side-column-name": self.column_names.side or "",
                 "input-column-name": self.column_names.input or "",
                 "output-column-name": self.column_names.output or "",