Claude Fable 5.1 and Claude Mythos 5.1

Anthropic has introduced Claude Fable 5.1 and Claude Mythos 5.1, described as the world's most advanced models for coding and knowledge work. These new models set a new standard in benchmarks, with Claude Fable 5.1 scoring 52.6% on Terminal-Bench-Science 0.1, more than double Fable 5. On Terminal-Bench 4.0, it achieved 55.8% compared to Fable 5's 42.0%. The models also offer similar or better results at a lower cost when set to lower effort levels.