Under the soon to be enacted EU AI laws such a bot would be limited-risk application (interaction with humans), the requirements for a text bot aren’t particularly high but also non-negotiable from a best practice POV: Stating front and centre that it’s an AI generated post. It’s also best practice to fulfil criteria necessary for high-risk systems voluntarily, the more you can fulfil I bet the less hostile people are going to be.

The library of congress has an executive summary of the thing.

(EU sources alas are a bit iffy at the moment there’s the commission version and the parliament amendments, haven’t seen a consolidated version yet. When will politicians start using proper VCS)