diff --git a/generic_rag/graphs/ret_gen.py b/generic_rag/graphs/ret_gen.py
index 63605d3..fd51259 100644
--- a/generic_rag/graphs/ret_gen.py
+++ b/generic_rag/graphs/ret_gen.py
@@ -27,7 +27,7 @@ class RetGenLangGraph:
         self.last_invoke = None
 
     def invoke(self, message: str) -> Union[dict[str, Any], Any]:
-        self.last_invoke = self.graph.invoke(message)
+        self.last_invoke = self.graph.invoke({"question": message})
         return self.last_invoke
     
     def _retrieve(self, state: State) -> dict: