Meta's confidence almost certainly rests on the employment contracts and IP assignment clauses, not on a legal theory that AI output is inherently copyrightable. The enterprise agreement with Anthropic assigns outputs to the licensee. The employment contract assigns work product to Meta. Those two documents together give Meta a defensible ownership position regardless of the authorship question. The interesting gap is for developers using personal accounts or consumer plans on side projects, where neither of those documents exists.

There’s so much FOMO right now around AI that no one is thinking clearly. I wouldn’t be so confident in your company.