You can only affect its behavior by a bit of prompting and the quality of results either it’s unalterable document retrieval system gives or by the quality of your own plugin-like external API services.
The AI will respond the best way it can, as it’s talking to the user, not to your backend services.
You can find what limited set of data will be more reliably retrieved. You can prompt the AI to give nicer or more productive language when retrieval or data browsing it performs doesn’t give answerable results. But you can’t fix the GPT system from the outside.