diff --git a/reme_ai/vector_store/vector_store_action_op.py b/reme_ai/vector_store/vector_store_action_op.py
index 7df2d68c..670e85b0 100644
--- a/reme_ai/vector_store/vector_store_action_op.py
+++ b/reme_ai/vector_store/vector_store_action_op.py
@@ -99,4 +99,4 @@ class VectorStoreActionOp(BaseAsyncOp):
         else:
             raise ValueError(f"invalid action={action}")
 
-        self.context.response.metadata["action_result"] = result
+        self.context.response.metadata["action_result"] = str(result)