AirTable User Validation

This would seem an easy use case, but all the GPT engines can't solve this. I am having the user enter email in VF chatbot. There is an API call to a user table in an Airtable base. If email is present then they are registered and it goes down one path. If it cannot find an email then it kicks off a registration process. Claude had me write up a custom code block after the API block. But the script can't set an internal variable correctly - ChatGPT, Gemini, and Perplexity couldn't resolve either. Anyone try this before? thanks