diff --git a/typescript-sdk/integrations/langgraph/python/ag_ui_langgraph/agent.py b/typescript-sdk/integrations/langgraph/python/ag_ui_langgraph/agent.py
index 54546b62a..13b224445 100644
--- a/typescript-sdk/integrations/langgraph/python/ag_ui_langgraph/agent.py
+++ b/typescript-sdk/integrations/langgraph/python/ag_ui_langgraph/agent.py
@@ -651,7 +651,13 @@ async def _handle_single_event(self, event: Any, state: State) -> AsyncGenerator
                     )
                 )
                 yield self._dispatch_event(
-                    ToolCallArgsEvent(type=EventType.TOOL_CALL_ARGS, tool_call_id=event["data"]["id"], delta=event["data"]["args"], raw_event=event)
+                    ToolCallArgsEvent(
+                        type=EventType.TOOL_CALL_ARGS,
+                        tool_call_id=event["data"]["id"],
+                        delta=event["data"]["args"] if isinstance(event["data"]["args"], str) else json.dumps(
+                            event["data"]["args"]),
+                        raw_event=event
+                    )
                 )
                 yield self._dispatch_event(
                     ToolCallEndEvent(type=EventType.TOOL_CALL_END, tool_call_id=event["data"]["id"], raw_event=event)