Working largely autonomously over 11 days on the open Prove2Me platform, many coordinated Claude agents produced the first complete, machine-checked proof of Fermat's Last Theorem in Lean 4 — over 13 million lines of code and roughly 29,500 new theorems, dwarfing Lean's existing main math library and closing out the 20-year-old Wiedijk "100 theorems" formalization challenge list. This episode digs into how a proof of that scale gets built and verified by a swarm of AI agents, why a machine-checked result is such a hard-to-fake data point, and what it does and doesn't tell us about the state of long-horizon autonomous AI work. Source: https://www.anthropic.com/research/formalizing-fermats-last-theorem