Subscribe

Artificial Intelligence

Anthropic Releases Claude Fable 5.2 and Mythos 5.2, Cutting Prices to $8/$40

Fable 5.2 is available on paid plans and the API, Mythos 5.2 stays limited to vetted cyber and life-sciences groups, and Anthropic's science claims are its own.

DailyMech Staff

Published

Last updated / Fact-checked on

Anthropic Releases Claude Fable 5.2 and Mythos 5.2, Cutting Prices to $8/$40
Pexels / Pixabay — Pixabay Content License

Circular star trails in a long-exposure night sky

Illustrative photo of circular star trails in a long-exposure night sky; it is not Anthropic, Claude, Fable, Mythos, or any person or event in this article. Photo: Pexels / Pixabay, Pixabay Content License.

Anthropic released Claude Fable 5.2 and Claude Mythos 5.2 on Monday, November 9. CNBC and The Verge timestamps place the news at about 11:00 AM PT; Anthropic's announcement page lists only the date.

Fable 5.2 is available now to paid Claude plans (Pro, Max, Ultra, Team and Enterprise) and through the API and major clouds at $8 per million input tokens and $40 per million output tokens, down from $10 and $50 for Fable 5.1, Anthropic says. CNBC puts the cut at 20%. Mythos 5.2 is not publicly available: Anthropic says it is limited to vetted organizations in its Cyber Verification Program and Life Sciences Verification Program.

At a glance

Item Detail Source/status
Release Fable 5.2 and Mythos 5.2, Nov. 9 Anthropic; CNBC/Verge timestamps ≈ 11:00 AM PT
Fable access Paid plans, API, AWS, Google Cloud, Microsoft Foundry Anthropic
Mythos access Vetted orgs in two Verification Programs only Anthropic
Standard price $8 / $40 per million input/output tokens Anthropic; was $10/$50
Standard speed Outputs up to 30% faster than 5.1 models Anthropic
Fast mode Optional; up to 2.5× token generation at $16/$80 Anthropic; Mythos fast mode for program members only
Fermat claim Formalization in 30 hours in prerelease testing Anthropic; separate from Sept. 11-day run; no outside review found
Black holes Two open physics problems solved Anthropic; preprints not read

What Anthropic released and what it costs

Anthropic says Fable and Mythos are the same underlying model. Fable carries cybersecurity and biology safeguards so it can be offered to all users; Mythos goes only to vetted organizations. Anthropic says Mythos 5.2 pricing starts at the same $8/$40.

On speed, Anthropic says the models generate outputs up to 30% faster than Claude Fable 5.1 and Claude Mythos 5.1 at standard rates.

Fast mode is a separate, optional setting. Anthropic says it speeds token generation by up to 2.5 times and costs $16 per million input tokens and $80 per million output tokens, twice the standard rates, The New Stack notes. Mythos fast mode is limited to Verification Program members. The 30% figure does not describe fast mode.

Anthropic reports a FrontierCode 2.0 score of 49.1% for Fable 5.2, versus 32.4% for Fable 5.1. The New Stack noted that Gemini 4 Carbon leads on AutomationBench. Anthropic still recommends Opus 5.5 for most coding and knowledge tasks, positioning Fable and Mythos for "the most ambitious, open-ended technical work."

Two Fermat claims, not one

Anthropic says that in prerelease testing, "a team of 1,000 Fable 5.2 agents fully formalized the theorem in just 30 hours, with minimal human intervention." Formalization means translating an existing proof of Fermat's Last Theorem into computer-checkable form; it is not a new proof. Anthropic says the run used no mathematical references. No independent outside review of the 30-hour run was found for this article.

That is a different run from the one on Anthropic's September 4 research page, which described an internal research model "roughly comparable to Claude Fable 5.1" working over 11 days, with a purpose-built harness and guidance from a researcher. Outside review described on that page concerns the earlier proof only.

Anthropic also says Fable 5.2 solved two open problems in theoretical physics involving black holes and holographic duality. Anthropic links two preprints; DailyMech did not read them, and they are not treated here as peer-reviewed or independently confirmed.

The pacing and IPO backdrop

CNBC frames the launch as Anthropic's first frontier release since CEO Dario Amodei called in September for slowing the pace of AI development. His essay, "We Must Pace the Frontier," says pacing "does not mean halting model training." CNBC quotes Dianne Penn, Anthropic's head of product management for research: "We called for pacing, not pausing."

CNBC also reports that Anthropic is readying an IPO that "could take place as soon as next week," targeting a $1 trillion–$1.5 trillion valuation, as CNBC previously reported. The company has not confirmed that timing in sources read for this article. DailyMech previously covered reported pre-Thanksgiving IPO plans and Anthropic's S-1.

What to watch

Independent evaluations of Fable 5.2; outside review of the 30-hour formalization and the black-hole preprints; System Card details; any confirmation of IPO timing; and whether the Verification Programs expand.

How we reported this

This article is based on Anthropic's November 9 announcement, product pages and docs, its September 4 Fermat research page, Amodei's September essay, and coverage by CNBC, The Verge and The New Stack, all fully read on November 9. Capability, speed, benchmark and science claims are Anthropic's. We did not read the System Card, the black-hole preprints or Anthropic's write-up of the 30-hour run. We did no hands-on testing.

Published and fact-checked November 9, 2026.

Sources

DailyMech used AI tools to help research and draft this article; it was fact-checked by our editors.

In Artificial Intelligence

From other sections

Sections

The Daily BriefingSample

Intelligence, distilled. Every morning.

Sample briefing. A five-minute read of the most important stories in AI and technology, once this list is real.

Sample form. It does not work. The address is not stored or sent.