diff --git a/cognee/api/v1/cognify/routers/get_cognify_router.py b/cognee/api/v1/cognify/routers/get_cognify_router.py
index 6809f089a..d40345f8e 100644
--- a/cognee/api/v1/cognify/routers/get_cognify_router.py
+++ b/cognee/api/v1/cognify/routers/get_cognify_router.py
@@ -38,7 +38,7 @@ class CognifyPayloadDTO(InDTO):
     dataset_ids: Optional[List[UUID]] = Field(default=None, examples=[[]])
     run_in_background: Optional[bool] = Field(default=False)
     custom_prompt: Optional[str] = Field(
-        default=None, description="Custom prompt for entity extraction and graph generation"
+        default="", description="Custom prompt for entity extraction and graph generation"
     )