diff --git a/libs/langgraph/langgraph/channels/topic.py b/libs/langgraph/langgraph/channels/topic.py
index 91e7027f90..5b081ee4cf 100644
--- a/libs/langgraph/langgraph/channels/topic.py
+++ b/libs/langgraph/langgraph/channels/topic.py
@@ -62,7 +62,7 @@ def from_checkpoint(self, checkpoint: Optional[list[Value]]) -> Self:
                 empty.values = checkpoint
         return empty
 
-    def update(self, values: Sequence[Union[Value, list[Value]]]) -> None:
+    def update(self, values: Sequence[Union[Value, list[Value]]]) -> bool:
         current = list(self.values)
         if not self.accumulate:
             self.values = list[Value]()