Anthropic Unveils Two Official Token-Saving Modes for Fable 5

Anthropic introduced Fable 5 and the restricted Mythos 5 in June, extending its most advanced capabilities to coding, knowledge work and scientific research. The two products share an underlying model but use different safeguards: Fable is designed for general availability, while Mythos access is limited to vetted organizations working in sensitive fields such as cybersecurity and life sciences. The split reflects the company’s effort to commercialize frontier systems without abandoning controls on potentially dangerous uses.

Anthropic launched Claude Fable 5.1 and Claude Mythos 5.1 on Sept. 1, 2026. Cache-read pricing for Fable fell 75% to $0.25 per million tokens, while input and output rates remained $10 and $50 per million tokens. Anthropic estimates typical workloads will cost 25% less and highly agentic work as much as 45% less. Fable 5.1 scored 52.6% on Terminal-Bench-Science 0.1, up from 24.7% for Fable 5, while revised cyber safeguards cut false-positive blocks by 60%. Eligible enterprise customers can use zero data retention ahead of a phased rollout of customer-controlled Enterprise Frontier Safeguards later this fall.

Anthropic’s Claude Fable 5 became the focus of a monthlong dispute over subscription access as the AI developer sought to contain the heavy computing costs associated with advanced models. The debate matters because it tests whether providers can preserve dependable access to flagship systems while balancing infrastructure constraints, customer expectations and the economics of fixed-price subscriptions.

Anthropic has now committed to keeping Fable 5 permanently available in its higher-tier subscription plans, ending uncertainty over the model’s removal. The company will, however, cut the applicable usage allowance to half its previous level. Customers on lower-priced plans will receive a one-time $100 credit before moving to usage-based billing, a shift designed to ease pressure on Anthropic’s computing capacity.