Hello AC,
Greetings, Thank you for reaching out to Microsoft Q&A forum!
OpenAI doesn’t provide a built-in way to calculate the Flesch-Kincaid score directly. You can, however, calculate it yourself after generating the text.
To adjust the output article's score, you could guide the model by refining your prompts. For example, if the score needs to be lower (simpler), ask for shorter sentences and simpler words. If it needs to be higher (more complex), prompt for longer sentences and more advanced vocabulary.
Please do let me know if you have further queries. Thank you!