Agents on Rails: Claude Fable 5.1 and GLM 5.3 Flash (formerly known as ox-alpha)

Claude Fable 5.1 dropped yesterday. See how it handles real Rails tasks, and where it landed on the leaderboard today. We also finally have a name for the stealth model from the last round . Fable 5.1: We have a new best. Fable 5.1 scored as well as Claude Opus 5 on accuracy, but surpassed it in all other marks (including price!). And it does security work now. Fable 5.1 solved 58 of 63 runs (92%) , matching Claude Opus 5 at the top of the leaderboard, and passed 20 of the 21 tasks at least o...