{"id":1791,"date":"2026-06-10T02:35:18","date_gmt":"2026-06-10T02:35:18","guid":{"rendered":"https:\/\/silvybrand.com\/?p=1791"},"modified":"2026-06-10T02:35:18","modified_gmt":"2026-06-10T02:35:18","slug":"anthropic-releases-claude-fable-5-mythos","status":"publish","type":"post","link":"https:\/\/silvybrand.com\/?p=1791","title":{"rendered":"Anthropic releases its first Mythos-class model Claude Fable\u00a0"},"content":{"rendered":"<p><br \/>\n<\/p>\n<div>\n<p class=\"duet--article--dangerously-set-cms-markup duet--article--standard-paragraph _1044qizi _18mzr4b1 _18mzr4b0 _19wv7tc1\">Anthropic just <a href=\"https:\/\/www.anthropic.com\/news\/claude-fable-5-mythos-5\">announced<\/a> Claude Fable 5, a new AI model it said is the most powerful model it has ever made widely available.<\/p>\n<\/div>\n<div>\n<p class=\"duet--article--dangerously-set-cms-markup duet--article--standard-paragraph _1044qizi _18mzr4b1 _18mzr4b0 _19wv7tc1\">According to the company, Fable 5 \u201cshows exceptional performance in software engineering, knowledge work, and vision,\u201d with its lead over other models growing as tasks become longer and more complex.<\/p>\n<\/div>\n<div>\n<p class=\"duet--article--dangerously-set-cms-markup duet--article--standard-paragraph _1044qizi _18mzr4b1 _18mzr4b0 _19wv7tc1\">Fable 5 marks the first broad release from Anthropic\u2019s Mythos class of AI models, after the company said the family was so capable at cybersecurity tasks that it was <a href=\"https:\/\/www.theverge.com\/ai-artificial-intelligence\/917644\/anthropic-claude-mythos-breach-humiliation\">too dangerous to release publicly<\/a>. Anthropic said the release was \u201cmade possible by new safeguards that block responses in specific high-risk areas,\u201d with the system falling back to Claude Opus 4.8 \u2014 a model it <a href=\"https:\/\/www.theverge.com\/ai-artificial-intelligence\/939094\/anthropic-claude-4-8-opus-honesty-effort\">praised<\/a> for \u201chonesty\u201d when it launched last month.<\/p>\n<\/div>\n<div>\n<p class=\"duet--article--dangerously-set-cms-markup duet--article--standard-paragraph _1044qizi _18mzr4b1 _18mzr4b0 _19wv7tc1\">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.<\/p>\n<\/div>\n<div>\n<p class=\"duet--article--dangerously-set-cms-markup duet--article--standard-paragraph _1044qizi _18mzr4b1 _18mzr4b0 _19wv7tc1\">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, \u201cbut with the safeguards lifted in some areas.\u201d For now, access appears limited to the steadily <a href=\"https:\/\/www.theverge.com\/ai-artificial-intelligence\/941792\/anthropic-claude-mythos-preview-expansion\">expanding group of organizations granted access<\/a> to Claude Mythos Preview through Anthropic\u2019s \u2014 <a href=\"https:\/\/www.theverge.com\/ai-artificial-intelligence\/917644\/anthropic-claude-mythos-breach-humiliation\">not entirely watertight<\/a> \u2014 private <a href=\"https:\/\/www.theverge.com\/ai-artificial-intelligence\/908114\/anthropic-project-glasswing-cybersecurity\">Project Glasswing initiative<\/a>. Those users will be able to upgrade to Mythos 5, Anthropic said, adding that it plans to \u201cexpand access over time through a more systematic trusted-access program.\u201d<\/p>\n<\/div>\n<div>\n<p class=\"duet--article--dangerously-set-cms-markup duet--article--standard-paragraph _1044qizi _18mzr4b1 _18mzr4b0 _19wv7tc1\">Anthropic did not respond on the record to <em>The Verge<\/em>\u2019s request for comment explaining how either model relates to Claude Mythos Preview or why the models are numbered \u201c5\u201d when there do not appear to be any previously released Mythos or Fable models.<\/p>\n<\/div>\n<div>\n<p class=\"duet--article--dangerously-set-cms-markup duet--article--standard-paragraph _1044qizi _18mzr4b1 _18mzr4b0 _19wv7tc1\">Pricing for both models is significantly higher than its former flagship model \u2014 <a href=\"https:\/\/platform.claude.com\/docs\/en\/about-claude\/models\/overview\">double<\/a> rates for Claude Opus 4.8, though it\u2019s half what users pay for Mythos Preview \u2014 at $10 per million input tokens and $50 per million output tokens, Anthropic said.<\/p>\n<\/div>\n<p><br \/>\n<br \/><a href=\"https:\/\/www.theverge.com\/news\/946725\/anthropic-releases-claude-fable-5-mythos\">Source link <\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Anthropic just announced Claude Fable 5, a new AI model it said is the most powerful model it has ever made widely available. According to the company, Fable 5 \u201cshows exceptional performance in software engineering, knowledge work, and vision,\u201d with its lead over other models growing as tasks become longer and more complex. Fable 5 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":1792,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[31,175,46],"class_list":["post-1791","post","type-post","status-publish","format-standard","has-post-thumbnail","category-gadgets","tag-ai","tag-anthropic","tag-news"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Anthropic releases its first Mythos-class model Claude Fable\u00a0 - Silvybrand Lifestyle Blog<\/title>\n<meta name=\"description\" content=\"It says new safeguards make it possible to release a Mythos-class model it previously said was too risky to make public.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/silvybrand.com\/?p=1791\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Anthropic releases its first Mythos-class model Claude Fable\u00a0 - 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