Chart capabilities: Assistants vs Completions

Hello,
I would appreciate some help understanding the difference in charting capabilities between gpt-4o-mini when prompted via assistant playground vs directly in the chat interface.
I expected the models to behave the same, and also that the result would be pretty much the same. However, via Assistants API, it seems like charts are not supported, it just would not make a chart (see screenshots below for a minimal working example)

Some other threads mention the limited capabilities of the assistants API but none directly related to charts

Does anyone have an explanation, a link to documentation, or a suggested workaround? Thanks!

ChatGPT is has a sophisticated set of functions and UI that is not available in the API.

In fact there is no UI in the API (the same for pretty much all API’s!)

You could build a similar system yourself however, if this was important to you and you are entirely responsible for it.