As OpenAI’s Astra proofs and DeepMind’s AlphaProof Nexus results circulate, Lean 4 certificates are emerging as the common way outsiders check AI-generated mathematics without trusting press copy alone. Public GitHub artifacts let anyone re-run checkers, which raises the bar after earlier overclaimed announcements. It matters because verification infrastructure now shapes scientific AI credibility as much as model size. Caveat: a machine-checked proof is only as meaningful as the theorem statement it encodes, so mathematicians still have to audit what was actually claimed.