diff --git a/metagpt/rag/schema.py b/metagpt/rag/schema.py
index 8f5828233..81db2a0d1 100644
--- a/metagpt/rag/schema.py
+++ b/metagpt/rag/schema.py
@@ -93,6 +93,7 @@ class ObjectNodeMetadata(BaseModel):
     """Metadata of ObjectNode."""
 
     is_obj: bool = Field(default=True)
+    obj: Any = Field(default=None, description="When retrieve, will reconstruct obj from obj_dict")
     obj_dict: dict = Field(..., description="Inplement rag.interface.RAGObject.model_dump(), e.g. obj.model_dump()")
     obj_cls_name: str = Field(..., description="The class name of object, e.g. obj.__class__.__name__")
     obj_mod_name: str = Field(..., description="The module name of class, e.g. obj.__class__.__module__")