If you have a paid Claude subscription, now is a good time to try Fable 5.2, Anthropic's most powerful available model. Pro subscribers can use it at no extra cost until November 17, while Max and Ultra subscribers can get up to three free limit resets.
Fable vs. Mythos: what's the difference?
On November 9, Anthropic released Claude Fable 5.2 and Claude Mythos 5.2. Essentially, they are two versions of the same model.
Fable 5.2 is available on all paid plans and has enhanced safety filters for cybersecurity and biology. Mythos 5.2 — is the same model with fewer restrictions. It is available only to Anthropic partners, primarily cybersecurity specialists.
Fable 5.2 responds up to 30% faster than previous versions, and its API costs 20% less than Fable 5.1.
What the model demonstrated
Before the release, Anthropic gave Fable 5.2 several challenging tasks, and the model completed every one of them:
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Built an operating system from scratch. An engineer gave it an empty folder and a brief assignment. Over eight days, Fable 5.2, working with a team of 1,000 AI agents, built a functioning system with drivers, a file system, windows and an installer. It runs on a regular laptop.
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Formalized the proof of Fermat's Last Theorem for computer verification in 30 hours. The theorem itself was proven back in the 1990s. The model rewrote the proof so that a computer could verify every step. A previous research version of Claude needed 11 days for the same task, while Opus 5.5 completed only a quarter of it in 18 hours.
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Solved two black hole physics problems that scientists had been unable to resolve. A calculation for one of them was proposed back in 2003, but no one had managed to complete it.
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Designed three electronic devices, including a voice hub and a USB speakerphone. All three work.
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Improved its ability to control robots. It can even handle tasks it wasn't specifically trained to perform.
All of these results come from Anthropic itself. There have been no independent verifications yet.
Who qualifies for a free limit reset
There are no bonuses on the free plan. For paid plans, the subscription must have been paid for before 9:00 PM Moscow time on November 9.
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Pro and standard Team seats. Until November 17, Fable is included in the subscription at no extra cost, but usage is limited to no more than half of the weekly limit. Subscribers also receive one free reset, which expires on the same date.
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Max, Ultra and premium Team seats. Subscribers receive one to three resets depending on how long they've been subscribed: less than six months — one, six months to one year — two, more than one year — three. These resets can be used until March 8, 2027.
A reset restores the weekly limit you've already used on Fable. It doesn't increase the limits themselves and doesn't apply to other Claude models. Once a reset has been used, it cannot be undone.
How to claim your reset
In Claude, open «Settings» → Usage, find the Limit resets section and click «Reset for free».
Keep in mind that Fable uses up limits faster than other Claude models. It's better to save your reset for a demanding task, such as coding a landing page, writing a scraping script or analyzing a large export of statistics. It's hardly worth spending it on simple questions.
