Since GPTs only have the one prompt I had to specialize it for a multi-step process with tool use (since it has to call an endpoint and draw an image in one go). Here's the prompt that I use in the GPT:
> Get the weather data for {location}. If the location is not on Earth (fictional
or otherwise), pick the place on Earth that is most visually similar to the
location. Before you get the weather, reason about which temperature unit is
most likely to be used at the location in question. That is the temperature unit
you should use when getting the weather.
> Here is the weather for the location "{location}":
> {weather["status"]}
> Use Dall-E to generate a beautiful illustration of the location in the style of
a wide post card filling up the entire image. Try to describe a scene that is
iconic and aesthetically pleasing for the location specified above, but also one
that can showcase the weather. (…)
