Anthropic launched Claude Fable 5.1 and Claude Mythos 5.1, calling them the world's most advanced models for coding and knowledge work. Fable 5.1 more than doubled Terminal-Bench-Science 0.1 to 52.6% and lifted Terminal-Bench 4.0 from 42.0% to 55.8%, while cutting cache-read prices 75% and typical agentic costs by up to 45%.
Key Takeaways
- ✓Scores 52.6% on Terminal-Bench-Science 0.1 (more than double Fable 5) and 55.8% on Terminal-Bench 4.0
- ✓Cache reads cost 75% less; real-world agentic workloads can drop about 25–45%
- ✓Fable 5.1 is generally available today; Mythos 5.1 is trusted-access, with Enterprise Frontier Safeguards rolling out this fall