Claude Fable 5.2 and Mythos 5.2: What's New in 2026

By PowerfulAI.tools Editorial Team

Anthropic has released two upgraded Claude models: Claude Fable 5.2 and Claude Mythos 5.2. Anthropic describes them as models "designed to tackle the most daunting technical challenges", with improvements in coding, reasoning and vision.

The update was announced on 9 November 2026 (US time), which was 10 November in Australia. Here is what launched, who can use it, what it costs and what it means if you use Claude.

Image: Anthropic

What launched

According to Anthropic, Fable and Mythos are the same underlying model. The difference is who gets access:

• Claude Fable 5.2 comes with strong safeguards around cybersecurity and biology, which is what lets Anthropic offer it to everyone.
• Claude Mythos 5.2 is for vetted organisations working in cybersecurity and biomedical research.

Anthropic says both models produce outputs up to 30% faster than the previous versions, Fable 5.1 and Mythos 5.1, and that they are available at a lower price.

Anthropic also says Fable 5.2 can act as an "Advisor", where smaller Haiku, Sonnet or Opus models consult it on harder problems, or as an "Orchestrator" that hands simpler tasks to smaller models.

What Anthropic says it can do

Anthropic's announcement lists several examples from its pre-release testing, including completing difficult software migrations, designing three working electronic devices, solving two open problems in black hole physics and formalising the proof of Fermat's Last Theorem in 30 hours.

On coding, Anthropic reports that Fable 5.2 scored 49.1% on its FrontierCode 2.0 benchmark at its highest effort setting, compared with 45.5% for Claude Opus 5.5. Anthropic notes these results come from its own internal runs.

Who can use it and where

Anthropic says Claude Fable 5.2 "is available today on all platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure". Developers can use it on the Claude Platform with the model ID claude-fable-5-2.

In the Claude apps, access depends on your plan, according to Anthropic's help centre:

• Free: Fable models are not available.
• Pro and standard Team seats: Fable normally runs on pay-as-you-go usage credits. As a launch offer, Fable is included until 16 November 2026 (US Pacific time) for up to 50% of weekly usage limits, plus one Fable limit reset.
• Max, Ultra and premium Team seats: Fable is included for up to 50% of weekly usage limits, and eligible subscribers get one to three Fable limit resets as a launch offer, depending on how long they have been subscribed.

Mythos 5.2 is not open to the general public. Cybersecurity professionals can apply through Anthropic's Cyber Verification Program, and life sciences researchers through its Life Sciences Verification Program. Claude Enterprise customers can also use Claude Security, which Anthropic says runs on the full model family, including Mythos 5.2.

What it costs

For developers using the API, Anthropic's official pricing for both models is (in US dollars):

• Standard: $8 per million input tokens and $40 per million output tokens.
• Fast mode: $16 per million input tokens and $80 per million output tokens. Anthropic says fast mode speeds up output by up to 2.5 times.

Fast mode is available in Claude Code, the Claude Platform, Claude models on Google Cloud and Microsoft Foundry. Fast mode for Mythos is limited to organisations in the verification programs.

For subscribers, Fable 5.2 is used within plan limits on Max, Ultra and premium Team seats. On Pro and standard Team seats it is paid with usage credits once the launch week ends.

What it means for ordinary users

For most people, Anthropic's own advice is to start with Claude Opus 5.5 for daily work and switch to Fable or Mythos for the most open-ended, demanding tasks. Fable 5.2 is aimed at hard technical work such as large coding projects, research and complex analysis, rather than everyday writing or quick questions.

On plans where Fable is included, it draws from your regular weekly limit and uses it faster than other models, so it makes sense to save it for the jobs that need it.

Anthropic also says that in early testing across claude.ai, Claude Code and Cowork, Fable 5.2 triggered about 55% fewer safeguard blocks than Fable 5.1.

For developers, the main news is a faster model at a lower price than Fable 5.1, plus the option to pay more for fast mode when speed matters.

How we checked

We checked every detail in this article against Anthropic's official announcement, Introducing Claude Fable 5.2 and Claude Mythos 5.2, and the Anthropic newsroom, plus Anthropic's help centre articles Claude Fable models on your plan and Claude Fable 5.2 launch offers, on 10 November 2026. Anthropic did not give the exact price cut compared with Fable 5.1, so we have left it out.

Updated 10 November 2026 to clarify which Claude plans include Fable 5.2.