Spam, promotions and newsletters are skipped by hard rules before the second call. What comes back is an action recommendation and reply settings, not a written or sent email. The author chose the confidence cutoffs, and the message text is sent to hosted Jev.
How you can use it
Borrow the sequence: make a cheap first decision to sort a message, skip categories needing no response, and only then ask about reply tone and purpose. Those answers provide settings for a possible reply rather than finished prose. Only supply email details you are willing to share with a third party.