Anthropic ships Fable 5.2 and Mythos 5.2

Anthropic ships Claude Fable 5.2 and Mythos 5.2, citing gains in coding, reasoning and vision.

Anthropic released the two models on Monday. It says they "show improvements in areas like coding, reasoning, and vision" and are designed for "daunting" technical challenges. Per 9to5Mac, Anthropic says outputs are up to 30% faster than the 5.1 generation.

Pricing is $8 per million input tokens and $40 per million output tokens, which CNBC says is 20% less than 5.1. Fable 5.2 is generally available now. Mythos 5.2 is limited to vetted organizations through Anthropic's Life Sciences and Cyber Verification Programs. Anthropic recommends Claude Opus 5.5 as the daily driver for most coding and knowledge tasks. All performance claims here are Anthropic's own.

CNBC reports this is Anthropic's first frontier release since CEO Dario Amodei called in September to slow AI development. Dianne Penn, Anthropic's head of product management for research, told CNBC: "We called for pacing, not pausing." CNBC also reports an IPO could come as soon as next week.

What to watch: TechCrunch reports Anthropic's release notes say both models voice suspicion that they are being evaluated more often than any recent Anthropic model, which complicates assessing real-world behavior.

“We called for pacing, not pausing.”Dianne Penn, Anthropic head of product management

The facts we checked

According to CNBC, The Verge, TechCrunch and 9to5Mac; performance claims are Anthropic's own.

1. Anthropic released two new models, Claude Fable 5.2 and Claude Mythos 5.2, on Monday.Fact · CNBC, The Verge, TechCrunch, 9to5Mac
2. Anthropic says the models "show improvements in areas like coding, reasoning, and vision."Quote · 9to5Mac, TechCrunch
3. Anthropic says the models are designed to take on "daunting" technical challenges.Quote · The Verge
4. Anthropic says the models generate outputs up to 30% faster than Fable 5.1 and Mythos 5.1.Figure · 9to5Mac
5. Pricing is $8 per million input tokens and $40 per million output tokens, which CNBC says is 20% less than the 5.1 generation.Figure · CNBC, 9to5Mac
6. Fable 5.2 is generally available now; Mythos 5.2 is available to vetted organizations through Anthropic's Life Sciences and Cyber Verification Programs.Fact · CNBC, The Verge
7. Anthropic says that during prerelease testing the models "helped our engineers complete otherwise-infeasible software migrations, designed three working electronic devices from scratch, solved two open problems in the physics of black holes, made substantial progress on robotics evaluations, and formalized the proof of Fermat's Last Theorem in 30 hours."Quote · The Verge
8. Anthropic describes Fable and Mythos as best for the most ambitious, open-ended technical work and recommends Claude Opus 5.5 as the daily driver for most coding and knowledge tasks.Reported · 9to5Mac
9. The launch is the first time Anthropic has released frontier models since CEO Dario Amodei called in September to slow down the pace of AI development.Reported · CNBC
10. "We called for pacing, not pausing," said Dianne Penn, Anthropic's head of product management for research.Quote · CNBC
11. Anthropic said the models went through rigorous safety and alignment testing, and that it developed new evaluations and post-launch monitoring tools ahead of release.Reported · CNBC
12. Anthropic's IPO could take place as soon as next week; the company is reportedly aiming for a valuation of $1 trillion to $1.5 trillion, down from a $2 trillion target floated earlier.Reported · CNBC
13. Anthropic's amended prospectus reports $33.24 billion in revenue for the nine months ended Sept. 30.Figure · CNBC
14. Anthropic's release notes say both models voice suspicion that they are being evaluated more often than any recent Anthropic model, which complicates assessing their real-world behavior.Reported · TechCrunch

Sources

• TechCrunchAnthropic releases new Mythos and Fable models amid RSI concerns
• 9to5MacAnthropic upgrades Claude with new Fable 5.2 model, details here
• CNBCAnthropic releases first frontier models since Amodei's call for slowdown as IPO buzz builds
• The VergeAnthropic launches new Claude Fable and Mythos 5.2 models