GoKawiilAI agents produce 613,000-line Lean formalization of CPython, find 418 bugs
A project using Opus 5.5 has generated 613,318 lines of Lean code that mirror CPython's internals function-by-function, testing each rewrite against real Python before attempting formal proofs. A second AI agent independently verifies each proof before it counts as accepted, and 4,071 functions have passed this check so far, yielding 18,898 theorems and lemmas across 1,539 files.