This is one of the first questions any buyer should ask, and the answer should be clear and in writing. Many enterprise AI vendors and model providers commit not to train on customer data, but the details matter, including what happens to prompts and outputs, how long they are kept and who can access them.
Buyers can verify the answer by asking for it in the contract or data processing agreement, reviewing the vendor’s security documentation and checking which model providers are used and what terms apply to them, and if a vendor cannot give a clear answer to any of those, that should come up in the review before anything is signed.