Claude Fable 5.2 and Mythos 5.2: what’s new and who gets it

If you’re on Claude Pro or a standard Team seat, you can use Anthropic’s top model this week without spending usage credits, up to half your weekly limit. And if you build on Claude, the most capable model just got 20% cheaper.

Anthropic released Claude Fable 5.2 and Claude Mythos 5.2 on 9 November. It says both improve on the 5.1 versions in coding, reasoning and vision, and produce answers up to 30% faster.

One model, two sets of guardrails

Fable and Mythos are the same underlying model. Fable has strong cybersecurity and biology safeguards, which is why anyone can use it. Mythos has fewer limits on that work, so direct access is only for organisations approved through Anthropic’s Cyber and Life Sciences Verification Programs.

That matters if you hoped to use Fable for security testing. Anthropic says Fable 5.2’s safeguards “will block most cybersecurity-related tasks”. Claude Enterprise customers can still get Mythos 5.2’s bug-hunting through Claude Security, which scans code for vulnerabilities.

What Anthropic says it can do

The launch post leans hard on big technical jobs. During its own testing, Anthropic says the model:

helped its engineers finish software migrations that were otherwise impractical
designed three working electronic devices from scratch
solved two open problems in the physics of black holes
built a prototype operating system that boots on a laptop, coordinating over 1,000 sub-agents for eight days.

Early-access companies such as Shopify, Uber and Oracle are quoted praising it. On Anthropic’s benchmark table, Fable 5.2 and Mythos 5.2 score ahead of Claude Opus 5.5 on almost every measure.

Cheaper to run, if you pay by the token

For developers on the Claude Platform, Fable 5.2 costs US$8 per million input tokens and US$40 per million output tokens. Fable 5.1 was US$10 and US$50.

An optional fast mode speeds up output by up to 2.5 times, for US$16 and US$80. Anthropic lists these prices in US dollars.

Fable 5.2 is also on Amazon Web Services, Google Cloud and Microsoft Azure. Australia is on Anthropic’s list of supported countries.

A free week for Pro subscribers

On a normal week, Pro subscribers pay for Fable with usage credits, according to Claude’s plans page. For the launch, Anthropic’s help article gives Pro plans and standard Team seats every Fable model for one week, up to half their weekly usage limit. They also get one Fable limit reset.

Max and Ultra plans, and premium Team seats, get one to three Fable resets, depending on how long they’ve subscribed. A reset gives back what you’ve spent on Fable this week; it doesn’t raise your limits.

Resets only go to accounts with paid billing in place before 10am Pacific time on 9 November. That’s 2am Perth time on 10 November. Free plans miss out.

Should you switch?

Probably not for everyday work. Anthropic itself recommends Opus 5.5 as the starting point for most coding and knowledge tasks. It positions Fable and Mythos for “the most ambitious, open-ended technical work”.

Spend the free week on a job that has stumped your usual model, such as a gnarly bug, big refactor or long research task. Starting a business? Our look at Claude’s startup offer covers the free year of Team for approved startups.

Checklist

Pick one hard task for the free week. Pro and standard Team users get Fable for a week, up to half their weekly limit. Save it for work your usual model struggles with.
Keep Opus 5.5 as your everyday model. Anthropic recommends starting there for most coding and knowledge tasks, and moving up to Fable only when needed.
Update the model name in your API code. Developers can switch to claude-fable-5-2 to get the new model and the lower US$8 and US$40 per million token prices.
Don’t plan security testing around Fable. Its safeguards block most cybersecurity tasks; security teams need Mythos 5.2 through the Cyber Verification Program, or Claude Security on Enterprise.