Antitrust is about abusing monopoly power so I'd guess not, but I'd love to hear an opinion from a US lawyer about the 'restraint of trade' angle. For example,

Antitrust is about abusing monopoly power so I'd guess not, but I'd love to hear an opinion from a US lawyer about the 'restraint of trade' angle. For example, I don't think automakers are allowed to ban competitors from making compatible parts for their cars. Similarly I think there have been cases where printer makers tried and failed to prevent competitors from making compatible ink cartridges for their printers. No automakers or printer manufacturers have a monopoly though. Requiring the use of certain tools to produce an otherwise identical product seems to me a violation along similar lines. I'd love to hear an expert opinion on it.