Claude Fable 5.1 dropped today, built on Mythos 5.1. Coding…

2026-09-02 06:35

Claude Fable 5.1 dropped today, built on Mythos 5.1. Coding scores 55.8% on Terminal-Bench, research doubled to 52.6%. Cache is 75% cheaper now, so real costs land 25-45% lower. API prices unchanged.