The classical Caffarelli-Kohn-Nirenberg partial regularity for Navier-Stokes is now machine-checked in Lean.

Vlad Vicol and Scott Armstrong launched an agent swarm to see how quickly they could formalize this from scratch.

It took about 36 hours, they used Claude Fable 5.1 to orchestrate and used up to 50 subagents at a time: 12 Luna-xhigh, 8 Astra-low, 10+ Leanstral at a time, 10+ deepseek-4.1-flash, and around 8-10 Opus/Sonnet, all going at once.