diff --git a/src/agent_toolkit/forestadmin/agent_toolkit/utils/forest_schema/action_values.py b/src/agent_toolkit/forestadmin/agent_toolkit/utils/forest_schema/action_values.py
index 363ee2302..cf0c25594 100644
--- a/src/agent_toolkit/forestadmin/agent_toolkit/utils/forest_schema/action_values.py
+++ b/src/agent_toolkit/forestadmin/agent_toolkit/utils/forest_schema/action_values.py
@@ -101,7 +101,7 @@ def value_to_forest(field: ActionField, value: Any) -> Any:
 
         elif field["type"] == ActionFieldType.COLLECTION and value:
             value = cast(CompositeIdAlias, value)
-            return "|".join(value)
+            return "|".join([str(v) for v in value])
 
         elif field["type"] == ActionFieldType.FILE and value:
             return ForestValueConverter._make_data_uri(value)
diff --git a/src/agent_toolkit/tests/utils/forest_schema/test_action_values.py b/src/agent_toolkit/tests/utils/forest_schema/test_action_values.py
index 29a8b2259..26541538b 100644
--- a/src/agent_toolkit/tests/utils/forest_schema/test_action_values.py
+++ b/src/agent_toolkit/tests/utils/forest_schema/test_action_values.py
@@ -156,6 +156,30 @@ def test_should_transform_multi_pk_into_composite(self):
             "1|2",
         )
 
+    def test_should_parse_correctly_pks_when_they_are_integer(self):
+        self.assertEqual(
+            ForestValueConverter.value_to_forest(
+                {
+                    "type": ActionFieldType.COLLECTION,
+                    "watch_changes": False,
+                    "label": "test_enum",
+                },
+                [1],
+            ),
+            "1",
+        )
+        self.assertEqual(
+            ForestValueConverter.value_to_forest(
+                {
+                    "type": ActionFieldType.COLLECTION,
+                    "watch_changes": False,
+                    "label": "test_enum",
+                },
+                [1, 2],
+            ),
+            "1|2",
+        )
+
     def test_should_transform_file_into_datauri(self):
         self.assertEqual(
             ForestValueConverter.value_to_forest(