As far as I can tell and from what I have read the API from Google is not supporting the thinking functionality - Also it cannot use images…
If you want to try it anyway you can select it from Agent mode now - You will be charged at the premium rate though - To get around this you can use your own API key in settings, ignore the verify error - This is available in Ai Studio and is free - I think you have a 50 call per day limit though…
Basically, I tried a quick and easy ToDo app and it had errors - Not a good look!..