diff --git a/libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py b/libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py
index d7d42ded6..8437f5d1b 100644
--- a/libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py
+++ b/libs/prebuilt/langgraph/prebuilt/chat_agent_executor.py
@@ -76,6 +76,7 @@ class AgentStatePydantic(BaseModel):
     messages: Annotated[Sequence[BaseMessage], add_messages]
 
     remaining_steps: RemainingSteps = 25
+    is_last_step: Optional[bool] = None
 
 
 class AgentStateWithStructuredResponse(AgentState):
@@ -965,3 +966,4 @@ __all__ = [
 
 
 
+