diff --git a/wren-ai-service/src/pipelines/indexing/instructions.py b/wren-ai-service/src/pipelines/indexing/instructions.py
index 4c376f2310..83a3f70707 100644
--- a/wren-ai-service/src/pipelines/indexing/instructions.py
+++ b/wren-ai-service/src/pipelines/indexing/instructions.py
@@ -166,12 +166,12 @@ async def run(
     @observe(name="Clean Documents for Instructions")
     async def clean(
         self,
-        instructions: List[Instruction],
+        instructions: Optional[List[Instruction]] = None,
         project_id: Optional[str] = None,
         delete_all: bool = False,
     ) -> None:
         await clean(
-            instructions=instructions,
+            instructions=instructions or [],
             cleaner=self._components["cleaner"],
             project_id=project_id,
             delete_all=delete_all,