Do I have to tell the patent office I used AI to draft my application?

In the US, no, not as a general rule. The USPTO's April 2024 guidance (89 FR 25609) states there is no general duty to inform the office that an AI tool was used to prepare an application. Existing duties still apply in full: the duty of candour, the duty to disclose information material to patentability, and the rule that a signature certifies the signer made a reasonable inquiry into everything in the paper. AI use becomes disclosable when it is material, for example if an AI system, rather than a natural person, contributed the subject matter of a claim. Such a claim is also unpatentable: the USPTO's revised inventorship guidance of 28 November 2025, which rescinded the February 2024 guidance, treats AI as a tool like software or laboratory equipment and requires that a natural person conceived each claimed invention.

Europe and the UK have no rule requiring you to declare AI drafting tools either, but the inventor must be a natural person, as the EPO's Boards of Appeal and the UK Supreme Court confirmed in the DABUS cases. The practical answer is to keep records of who conceived what, so that inventorship is defensible if challenged, and to have a registered attorney review and sign the filing, because that person carries the verification duty regardless of which tools were used. See also Can AI invent a patent, or be listed as an inventor?