Anthropic releases its first Mythos-class model Claude Fable

Anthropic 发布其首个“神话级”（Mythos-class）模型 Claude Fable

Anthropic just announced Claude Fable 5, a new AI model it said is the most powerful model it has ever made widely available. Anthropic 刚刚发布了 Claude Fable 5，这是该公司迄今为止向公众广泛提供的最强大的 AI 模型。

According to the company, Fable 5 “shows exceptional performance in software engineering, knowledge work, and vision,” with its lead over other models growing as tasks become longer and more complex. 据该公司称，Fable 5 在“软件工程、知识工作和视觉处理方面表现卓越”，且随着任务变得越发冗长和复杂，其相较于其他模型的领先优势也愈发明显。

Fable 5 marks the first broad release from Anthropic’s Mythos class of AI models, after the company said the family was so capable at cybersecurity tasks that it was too dangerous to release publicly. Anthropic said the release was “made possible by new safeguards that block responses in specific high-risk areas,” with the system falling back to Claude Opus 4.8 — a model it praised for “honesty” when it launched last month. Fable 5 是 Anthropic“神话级”（Mythos）AI 模型系列首次面向大众发布。此前，该公司曾表示该系列模型在网络安全任务中能力过强，公开发布存在风险。Anthropic 表示，此次发布之所以成为可能，是因为采用了“新的安全防护措施，能够拦截特定高风险领域的响应”，系统会自动回退至 Claude Opus 4.8——即上个月发布时因“诚实”而备受赞誉的模型。

Anthropic singled out cybersecurity and biology as two domains where the safeguards may block responses, both areas widely considered sensitive topics for advanced AI systems. The company said that in testing, 95 percent of Fable sessions ran entirely on Fable responses, without falling back to Opus 4.8. Anthropic 特别指出，网络安全和生物学是安全防护措施可能拦截响应的两个领域，这两个领域在高级 AI 系统中被广泛视为敏感话题。该公司表示，在测试中，95% 的 Fable 会话完全由 Fable 模型响应，无需回退至 Opus 4.8。

The company is also releasing Claude Mythos 5, but provided few details on what that means. In a blog, Anthropic said Mythos 5 is the same underlying model as Fable 5, “but with the safeguards lifted in some areas.” For now, access appears limited to the steadily expanding group of organizations granted access to Claude Mythos Preview through Anthropic’s — not entirely watertight — private Project Glasswing initiative. Those users will be able to upgrade to Mythos 5, Anthropic said, adding that it plans to “expand access over time through a more systematic trusted-access program.” 该公司还发布了 Claude Mythos 5，但并未提供太多细节。Anthropic 在博客中表示，Mythos 5 与 Fable 5 使用相同的底层模型，但“在某些领域取消了安全限制”。目前，该模型的访问权限似乎仅限于通过 Anthropic 的“Project Glasswing”私有计划获得 Claude Mythos Preview 权限的组织，且该计划的准入机制并非完全严密。Anthropic 表示，这些用户将能够升级到 Mythos 5，并补充称计划“通过更系统的可信访问计划逐步扩大访问范围”。

Anthropic did not respond on the record to The Verge’s request for comment explaining how either model relates to Claude Mythos Preview or why the models are numbered “5” when there do not appear to be any previously released Mythos or Fable models. 对于 The Verge 提出的置评请求，Anthropic 未作正式回应。这些请求包括解释这两款模型与 Claude Mythos Preview 的关系，以及为何在之前并未发布过任何 Mythos 或 Fable 模型的情况下，这两款模型会被命名为“5”。

Pricing for both models is significantly higher than its former flagship model — double rates for Claude Opus 4.8, though it’s half what users pay for Mythos Preview — at $10 per million input tokens and $50 per million output tokens, Anthropic said. Anthropic 表示，这两款模型的定价均显著高于其之前的主力模型——价格是 Claude Opus 4.8 的两倍，但仅为 Mythos Preview 用户支付费用的一半，即每百万输入 Token 10 美元，每百万输出 Token 50 美元。