Claude Fable 5.2: price, benchmarks and how to try it.

Claude Fable 5.2 is Anthropic’s newest top-tier model, released on 9 November 2026 together with Claude Mythos 5.2. Anthropic says both are built for “the most daunting technical challenges”, and that they improve on Fable 5.1 and Mythos 5.1 in coding, reasoning and vision while costing less. Here is what Claude Fable 5.2 is, what changed, what it costs and how to try it.

What is Claude Fable 5.2?

Anthropic says Claude Fable and Claude Mythos are the same underlying model. Fable ships with strong cybersecurity and biology safeguards, which lets Anthropic offer it to all users. Mythos is the version without those blocks, available only to vetted organizations through Anthropic’s Cyber Verification Program and Life Sciences Verification Program.

According to the Claude Platform docs, Claude Fable 5.2 (model ID `claude-fable-5-2`) is “for demanding reasoning and long-horizon agentic work”, such as agent sessions that run for hours, multistep deep research, and analysis carried through to a finished document, spreadsheet or deck. It has a 1M-token context window, 128K max output tokens, takes text and images as input and returns text, and has adaptive thinking that is always on, with `high` as the default effort. The docs list a reliable knowledge cutoff of June 2026.

What’s new in Claude Fable 5.2 and Mythos 5.2

• Faster output. Anthropic says the new models generate output up to 30% faster than Fable 5.1 and Mythos 5.1.
• Lower price. Both cost $8 per million input tokens and $40 per million output tokens.
• Fast mode. An optional fast mode speeds up token generation by up to 2.5 times, at $16 per million input tokens and $80 per million output tokens.
• Fewer false blocks. Anthropic says it saw about 55% fewer blocks with Fable 5.2 than Fable 5.1 in early testing, about 60% fewer in cybersecurity and 40% fewer in biology. Blocked cyber queries are answered by Opus 4.8 and blocked biology queries by Opus 5.
• Advisor and orchestrator roles. Anthropic says Fable 5.2 can act as an advisor that Haiku, Sonnet or Opus models consult on harder problems, or as an orchestrator that hands simpler tasks to smaller models.

Claude Fable 5.2 benchmarks

Anthropic published a benchmark table comparing Fable 5.2 with Fable 5.1, Claude Opus 5.5, GPT-6 Astra and Gemini 4 Carbon. These are Anthropic’s own numbers, with safeguards on and each model at its highest available effort unless noted:

• FrontierCode 2.0 (agentic coding): 49.1% at Xhigh effort, versus 45.5% for Opus 5.5, 42.8% for GPT-6 Astra and 41.1% for Gemini 4 Carbon (Medium effort). Anthropic says it is the highest score of any released model it has tested.
• FrontierSWE v2: 69.9%, versus 62.3% for Opus 5.5 and 65.5% for GPT-6 Astra.
• OSWorld 2.1 (computer use, offline set, partial): 89.3%, versus 87.2% for Opus 5.5.
• Humanity’s Last Exam (with tools): 74.2%, versus 67.7% for Opus 5.5 and 57.2% for GPT-6 Astra.
• RoboDojo Sim (robot control, run internally): 64.9%, versus 29.8% for GPT-6 Astra and 27.6% for Fable 5.1.
• AutomationBench (business workflows): 51.4%, behind Gemini 4 Carbon’s 53.9% but ahead of Opus 5.5’s 42.5%.

Anthropic also says that at High effort, Fable 5.2 scored about level with Opus 5.5’s best FrontierCode result (45.3% versus 45.5%) for roughly half the cost per task. For cybersecurity, it says Mythos 5.2 found 10.2% more vulnerabilities than Opus 5.5 and 14.4% more than Mythos 5.1 on its internal CVE Rediscovery evaluation.

What Anthropic says Fable 5.2 has done

Anthropic describes several pre-release projects. A team of agents running an earlier version of Fable 5.2 migrated a production service from Python to Rust that now starts about 26 times faster. One engineer had it build a prototype operating system from an empty folder, coordinating over 1,000 subagents for eight days. A team of 1,000 Fable 5.2 agents formalized the proof of Fermat’s Last Theorem in Lean in 30 hours. Anthropic also says Fable 5.2 solved two open problems in black hole physics and, working with circuit board maker Diode, designed three working electronic devices: a voice-assistant hub, a USB speakerphone and a handheld virtual pet.

Claude Fable 5.2 price and availability

Anthropic says Claude Fable 5.2 is available today on all platforms, including Amazon Web Services, Google Cloud and Microsoft Azure. The docs list it on the Claude API as `claude-fable-5-2`, on Amazon Bedrock as `anthropic.claude-fable-5-2`, and on Claude Platform on AWS, Claude Models on Google Cloud and Microsoft Foundry. Pricing is $8 per million input tokens and $40 per million output tokens; the docs add that Batch API requests are 50% off and prompt cache reads cost 2.5% of the base input price on Fable 5.2.

For subscribers, Anthropic says eligible paid plans get extra Fable usage during launch week, with one to three Fable resets depending on how long they have subscribed. General access to Claude Mythos 5.2 stays limited to organizations accepted into Anthropic’s verification programs. Claude Enterprise customers can use Claude Security, Anthropic’s code-scanning product, which now runs on Mythos 5.2.

Who Claude Fable 5.2 is for

Anthropic positions Fable and Mythos for the most ambitious, open-ended technical work. For most coding and knowledge tasks, it recommends starting with Claude Opus 5.5, which it calls its “strongest daily driver”, and moving up to Fable when the job needs it, or down to Claude Sonnet 5.5 or Claude Haiku 5.5 for lighter work. Note that Fable 5.2’s safeguards block most cybersecurity tasks, so security teams need Mythos 5.2.

How to try Claude Fable 5.2

1. Use it in the Claude apps or Claude Code if you are on an eligible paid plan.
2. Call `claude-fable-5-2` on the Claude Platform, or use the Bedrock, Google Cloud or Microsoft Foundry model IDs listed in the Claude Fable 5.2 docs↗ (opens in a new tab).
3. Start at the default effort and raise it only for harder tasks, since Anthropic’s results show cost rising with effort.
4. If you work in cybersecurity or life sciences, apply to Anthropic’s verification programs for Mythos 5.2 access.

What people are building with Claude Fable

The build below was made with the earlier Claude Fable 5.1. One creator used Claude Fable 5.1 to drive a robot arm zero-shot on a rover, planning goals from a single wrist camera. Anthropic reports a higher RoboDojo Sim score for Fable 5.2 (64.9%). No Claude Fable 5.2 builds are listed yet; one may be added after curation.

Claude Fable 5.2 FAQ