Anthropic Releases Claude Fable 5.2 and Mythos 5.2 With a 20 Percent Price Cut

Anthropic released Claude Fable 5.2 and Claude Mythos 5.2 on Monday, Nov. 9, its strongest pair of AI models so far, and cut their price by 20 percent on the same day. The two releases are one model sold in two forms. Fable 5.2 is open to all paying users, while Mythos 5.2 is held back for vetted security and life sciences teams.

Both models cost 8 dollars per million input tokens and 40 dollars per million output tokens, down from 10 and 50 dollars for the 5.1 versions. Anthropic says the new models produce output up to 30 percent faster than their predecessors, and an optional fast mode doubles the price for up to 2.5 times the generation speed.

One model, two levels of access

Fable 5.2 went on sale at once on paid Claude plans, in Claude Code and through the Claude Platform, Amazon Web Services, Google Cloud and Microsoft Azure. Its context window holds one million tokens.

Mythos 5.2 uses the same underlying model with different safeguards. Access is limited to organizations in Anthropic's Cyber Verification Program and Life Sciences Verification Program, because the model is built for work such as scanning code for weaknesses, where open access would carry more risk.

Scores Anthropic published at launch

On FrontierCode 2.0, a coding test that checks whether a software patch is good enough to merge into a real project, Fable 5.2 scored 49.1 percent at its Xhigh effort setting. Fable 5.1 scored 32.4 percent on the same test, OpenAI's GPT-6 Astra scored 42.8 percent and Google's Gemini 4 Carbon scored 41.1 percent in Anthropic's launch comparison. At the High setting, an average FrontierCode task cost 6.72 dollars with Fable 5.2.

In Anthropic's own security evaluation, Mythos 5.2 rediscovered 89.6 percent of known vulnerabilities, up from 78.3 percent for Mythos 5.1. In a separate demonstration, about 1,000 agents running an early build of Fable 5.2 formalized the existing proof of Fermat's Last Theorem in the Lean proof language in about 30 hours.

Anthropic still recommends its cheaper Opus 5.5, at half the standard token price, as the starting model for most coding and knowledge work.

A launch in IPO week

CNBC reported that this is Anthropic's first frontier model release since chief executive Dario Amodei published an essay in September calling for the industry to slow capability gains, and that the company's stock market listing could come as soon as next week. The release also lands less than two weeks after Google announced Gemini 4 Carbon on Oct. 28. Carbon remains in limited release, while Fable 5.2 is available to any paying Claude customer from day one.