Claude Fable 5.2 and Mythos 5.2

Anthropic's 9 November 2026 post introduces Claude Fable 5.2 and Claude Mythos 5.2. Anthropic says they are the same underlying model. Fable carries cybersecurity and biology safeguards and is the one Anthropic makes available generally. Organizations can apply for Mythos through the Life Sciences Verification Program or the Cyber Verification Program.

Anthropic says the models generate output up to 30% faster than Fable 5.1 and Mythos 5.1. The price is $8 per million input tokens and $40 per million output tokens. An optional fast mode speeds token generation by up to 2.5 times, at $16 per million input tokens and $80 per million output tokens. The API model id is claude-fable-5-2. Fable 5.2 is on the Claude Platform, Amazon Web Services, Google Cloud, and Microsoft Azure. Fast mode is on Claude Code, the Claude Platform, Claude Models on Google Cloud (Anthropic managed and Google managed), and Microsoft Foundry. Mythos fast mode is only for organizations in the verification programs.

Anthropic says Fable and Mythos are for the most ambitious technical work, and that most coding and knowledge tasks should start on Claude Opus 5.5. On FrontierCode 2.0, Anthropic reports Fable 5.2 at 49.1% with Xhigh effort, Fable 5.1 at 32.4%, and Opus 5.5 at 45.5%. Eligible paid plans that already include Fable get one to three extra Fable resets this week, based on how long the subscription has run. Fable is included for up to 50% of weekly usage limits on Pro plans and on standard seats of the Team plan.

GitHub's changelog the same day says Claude Fable 5.2 is generally available in GitHub Copilot for Pro+, Max, Business, and Enterprise, with a gradual rollout. You can select it in Visual Studio Code, Visual Studio, Copilot CLI, the Copilot coding agent, the Copilot app, github.com, GitHub Mobile, JetBrains IDEs, Xcode, and Eclipse. Business and Enterprise administrators must turn on the Claude Fable 5.2 policy. It is off by default. GitHub says the model requires data retention by default so Anthropic can run safety classifiers, and that retained data is not used to train Anthropic's models. Other Claude models in Copilot, except Fable 5, Fable 5.1, and Fable 5.2, stay on zero data retention. Eligible enterprises can keep zero data retention on those three Fable models through the end of the calendar year, then Enterprise Frontier Safeguards. GitHub says Copilot bills the model at provider list pricing under usage-based billing. That note is the Copilot changelog (opens in a new tab).

Who it's for: someone with a hard technical job who already pays for Claude or Copilot, and who can accept Fable's data-retention default.

Fits: Best for Writing stays Claude, for a draft that has to sound like a person. Fable 5.2 is the technical model in that family, not the reason for the writing rank. Best for Vibe Coding stays Cursor. GitHub Copilot can now select this model, and Claude Code can use the fast mode. The writing guide, the Claude alternatives, and the coding guide are unchanged. The verdict is unchanged.