diff --git a/api/core/workflow/entities/variable_pool.py b/api/core/workflow/entities/variable_pool.py
index 3ec7a28bd1..d92134db58 100644
--- a/api/core/workflow/entities/variable_pool.py
+++ b/api/core/workflow/entities/variable_pool.py
@@ -18,8 +18,6 @@ from core.workflow.constants import (
 )
 from core.workflow.system_variable import SystemVariable
 from factories import variable_factory
-from services.rag_pipeline import rag_pipeline
-
 VariableValue = Union[str, int, float, dict, list, File]
 
 VARIABLE_PATTERN = re.compile(r"\{\{#([a-zA-Z0-9_]{1,50}(?:\.[a-zA-Z_][a-zA-Z0-9_]{0,29}){1,10})#\}\}")
@@ -76,7 +74,7 @@ class VariablePool(BaseModel):
                 rag_pipeline_variables_map[node_id][key] = value
             for key, value in rag_pipeline_variables_map.items():
                 self.add((RAG_PIPELINE_VARIABLE_NODE_ID, key), value)
-    
+
 
     def add(self, selector: Sequence[str], value: Any, /) -> None:
         """