Update presentation_api.py

presentation_api.py

@@ -128,7 +128,7 @@ async def chat(input_data: ChatInput):
                 yield f"{json.dumps({'type': 'tool_start', 'tool': event['name'], 'input': tool_input})}\n"
             
             elif kind == "on_tool_end":
-                tool_output = str(event['data'].get('output', ''))
+                tool_output = event['data'].get('output', '')
                 yield f"{json.dumps({'type': 'tool_end', 'tool': event['name'], 'output': tool_output})}\n"
 
     return EventSourceResponse(