Anthropic brings Mythos to the masses with Claude Fable 5, its most powerful generally available model ever

Anthropic today launched two new AI models — Claude Fable 5 and Claude Mythos 5 — marking the company’s first broad release of the powerful “Mythos-class” AI capabilities it previously made available only to participating organizations in its restricted cybersecurity program, Project Glasswing , which it announced two months ago. The company says Fable 5, which is the version most users and developers will get starting today, exceeds every Claude model it has previously made generally available — featuring stronger performance across software engineering, knowledge work, vision, scientific research and long-running tasks. It smashes the existing benchmarks and comes atop on nearly all of them, though the prior Claude Mythos Preview version of the model still takes the top spots on computer use and multidisciplinary reasoning (see benchmark chart below and here ). The new Claude Mythos 5, by contrast, is a more restricted, upgraded version of the prior, similarly restricted Mythos Preview model. As such, it has certain safeguards lifted for approved users, including Anthropic's cybersecurity partners in its Project Glasswing effort, and select biology researchers. The key difference is that the general purpose Fable 5 wraps the same underlying Mythos-class capability in new safeguards. Anthropic says requests involving certain high-risk areas — including cybersecurity, biology and chemistry, and model distillation — are automatically routed to Claude Opus 4.8 instead, with users notified when that happens. The company says more than 95% of Fable sessions run entirely on Fable’s own responses, with no fallback, and that internal and external red-teaming efforts found no “universal jailbreaks” after more than 1,000 hours of testing. Anthropic says Fable 5 is available to the general public today through its website, apps, and API , but that Mythos 5 will initially only be made available to users who already have access to the older Claude Mythos Preview. Pricing, access and a tricky rollout Anthropic is pricing both Fable 5 and Mythos 5 at $10 per million input tokens and $50 per million output tokens. The company says that is less than half the price of Claude Mythos Preview, but still ranks as the most expensive of major AI models available globally. VentureBeat Frontier AI Model API Pricing Snapshot Model Input Output Total Cost Source MiMo-V2.5 Flash $0.10 $0.30 $0.40 Xiaomi MiMo deepseek-v4-flash $0.14 $0.28 $0.42 DeepSeek deepseek-v4-pro $0.435 $0.87 $1.305 DeepSeek MiniMax-M3 $0.30 $1.20 $1.50 MiniMax Gemini 3.1 Flash-Lite $0.25 $1.50 $1.75 Google Qwen3.7-Plus $0.40 $1.60 $2.00 Alibaba Cloud MiMo-V2.5 $0.40 $2.00 $2.40 Xiaomi MiMo Grok 4.3 (low context) $1.25 $2.50 $3.75 xAI GLM-5 $1.00 $3.20 $4.20 Z.ai Kimi-K2.6 $0.95 $4.00 $4.95 Moonshot/Kimi GLM-5.1 $1.40 $4.40 $5.80 Z.ai Grok 4.3 (high context) $2.50 $5.00 $7.50 xAI Qwen3.7-Max $2.50 $7.50 $10.00 Alibaba Cloud Gemini 3.5 Flash $1.50 $9.00 $10.50 Google Gemini 3.1 Pro Preview (≤200K) $2.00 $12.00 $14.00 Google GPT-5.4 $2.50 $15.00 $17.50 OpenAI Gemini 3.1 Pro Preview (>200K) $4.00 $18.00 $22.00 Google Claude Opus 4.8 $5.00 $25.00 $30.00 Anthropic GPT-5.5 $5.00 $30.00 $35.00 OpenAI Claude Fable 5 / Claude Mythos 5 $10.00 $50.00 $60.00 Anthropic For developers, Fable 5 is available through the Claude API as claude-fable-5 . Anthropic says Fable 5 is fully available today on the Claude API and on consumption-based Enterprise plans. For subscription users, the rollout is more complicated. Anthropic says Fable 5 will be included on Pro, Max, Team and seat-based Enterprise plans at no extra cost from today through June 22. On June 23, the company plans to remove Fable 5 from those plans, after which using it will require usage credits. Anthropic says it aims to restore Fable 5 as a standard part of subscription plans as quickly as possible. The difference between Fable 5 and Mythos 5 Anthropic is not presenting Fable 5 and Mythos 5 as two separate models in the usual “small versus large” sense. Instead, they appear to share the same base capability level. The difference is access control — that is, how easily it will be for users to get their hands on the models, and the guardrails embedded in each. As previously mentioned Fable 5 includes a new safeguard layer that detects certain high-risk requests — including cybersecurity, biology and chemistry, and attempts to distill the model’s capabilities into other systems — and routes those requests to Claude Opus 4.8. Mythos 5 lifts some of those restrictions for trusted users working in approved domains. In practical terms, Mythos 5 is more powerful for sensitive cyber and biology work because it can answer in areas where Fable 5 falls back. For most ordinary enterprise and developer tasks, however, Anthropic says Fable 5 performs effectively the same as Mythos 5. The launch also signals how Anthropic plans to b