Anthropic's Fable 5.1 Doubles Performance: How It Shakes Up the Market?

Anthropic released Claude Fable 5.1 and Mythos 5.1, achieving double the performance of its predecessor on the Terminal-Bench-Science 0.1 test. Fable 5.1 scored 52.6%, surpassing its predecessor's 24.7% and Opus 5's 29.0%. On Terminal-Bench 4.0, it achieved 55.8%, outperforming Opus 5's 52.3%. In the Humanity's Last Exam, Fable 5.1 hit 65.0% with tools, beating Opus 5. Mythos 5.1, with lighter security filters, scored 60.9%. Opus 5, launched at half the price of Fable 5, was undercut by Fable 5.1 across all benchmarks, making the flagship model redundant for many users. Fable 5.1 costs $10 input/$50 output, twice as much as Opus 5's $5/$25. Access follows the same split as Fable 5, with Pro plans billing at API rates and Max plans offering free access up to 50% of weekly usage. Will this shift boost Anthropic's market share? Watch this space.