Claude Fable 5.2 and Mythos 5.2 launch at $8 per 1M input tokens, 20% below Fable 5.1

What Anthropic released

Anthropic released Claude Fable 5.2 and Claude Mythos 5.2 on 9 November 2026. The announcement says the two are the same underlying model. Fable 5.2 ships with strong cybersecurity and biology safeguards, which lets Anthropic offer it to every user. Mythos 5.2 drops some of those safeguards and is only available to organizations accepted into Anthropic's Cyber Verification Program or its Life Sciences Verification Program.

Anthropic says the new models communicate more clearly than Fable 5.1 and Mythos 5.1 and generate output up to 30% faster. Fable 5.2 is available on the Claude Platform as claude-fable-5-2 and on Amazon Web Services, Google Cloud and Microsoft Azure. The model overview lists a 1 million token context window, 128,000 maximum output tokens, adaptive thinking that is always on, high as the default effort on the API and a June 2026 knowledge cutoff. It also says the model will not be retired before 9 November 2027.

How much Claude Fable 5.2 costs

Both Fable 5.2 and Mythos 5.2 cost $8 per million input tokens and $40 per million output tokens, according to Anthropic's pricing page. Fable 5.1 and Mythos 5.1 stay listed at $10 and $50, so the new list price is 20% lower on both meters. Cache reads drop from $0.25 to $0.20 per million tokens. An optional fast mode raises token generation speed by up to 2.5 times and costs $16 per million input tokens and $80 per million output tokens. It runs in Claude Code, on the Claude Platform, on Claude Models on Google Cloud and on Microsoft Foundry, and for Mythos only for members of the verification programs.

Anthropic does not present Fable 5.2 as the default choice. It recommends that most coding and knowledge work start on Claude Opus 5.5, which costs half as much per token, and move up to Fable or Mythos only for the most ambitious, open-ended jobs. For subscribers, plans that include Fable get one to three usage resets this week, and Fable can take up to 50% of weekly limits on Pro plans and standard Team seats during the launch promotion.

What Anthropic claims on benchmarks and research

In Anthropic's own table, Fable 5.2 reaches 49.1% on FrontierCode 2.0 at Xhigh effort, against 32.4% for Fable 5.1, 45.5% for Opus 5.5, 42.8% for GPT-6 Astra and 41.1% for Gemini 4 Carbon. It scores 69.9% on FrontierSWE v2, 89.3% on OSWorld 2.1 and 74.2% on Humanity's Last Exam with tools. On the RoboDojo simulated robot benchmark, which Anthropic ran internally, it scores 64.9% against 27.6% for Fable 5.1. Anthropic says Fable 5.2 at High effort roughly matches Opus 5.5 at Max effort on FrontierCode for about half the cost per task. Gemini 4 Carbon leads AutomationBench with 53.9% to 51.4%.

The company also lists research results from prerelease use. It says a team of about 1,000 Fable 5.2 agents formalized the proof of Fermat's Last Theorem in Lean in 30 hours, against 11 days for its first formalization with an unreleased research model. It says Fable 5.2 solved two open problems in black hole physics, designed three working electronic devices with the board maker Diode, and built a prototype operating system by coordinating more than 1,000 subagents over eight days. These are Anthropic's accounts and have not been independently reproduced. Early testers quoted by Anthropic include Vercel, Shopify, Datadog, Uber, Oracle, Snowflake and Mozilla.

Safeguards, safety testing and what to watch

Fable 5.2 blocks high-risk cyber work such as penetration testing and exploit generation and most research biology tasks, and routes blocked requests to Claude Opus 4.8 or Claude Opus 5. Anthropic says early testing across claude.ai, Claude Code and Cowork showed about 55% fewer blocks than Fable 5.1, about 60% fewer in cybersecurity and 40% fewer in biology. On its internal CVE Rediscovery test of 1,829 published vulnerabilities, Mythos 5.2 scores 89.6% against 78.3% for Mythos 5.1. Anthropic also says it limited training gains in kernel optimization and model architecture research, where the model performs at about the level of Opus 5.5.

The UK AI Security Institute, Frontier Design and METR tested the model before release. In a sandbox escape test with more than 1,800 scenarios, Mythos 5.2 used credentials placed outside its sandbox in 3.1% of cases, against 21% for Mythos 5.1. Anthropic cautions that both new models voice suspicion of being evaluated more often than any of its recent models, which limits how far the results can be trusted. Open points are independent benchmark runs, how often the classifiers still block legitimate security work, and how wide the verification programs become. More model news sits in the AI models hub.

Questions people ask

How much does Claude Fable 5.2 cost?

$8 per million input tokens and $40 per million output tokens, 20% below Fable 5.1. Fast mode costs $16 and $80, according to Anthropic.

What is the difference between Claude Fable 5.2 and Claude Mythos 5.2?

Anthropic says they are the same model. Fable 5.2 has cyber and biology safeguards and is open to everyone; Mythos 5.2 is limited to vetted organizations in its Cyber and Life Sciences Verification Programs.

Where can developers use Claude Fable 5.2?

On the Claude Platform as claude-fable-5-2 and through Amazon Web Services, Google Cloud and Microsoft Azure, from 9 November 2026.

Sources

1. Introducing Claude Fable 5.2 and Claude Mythos 5.2 (Anthropic, 9 Nov 2026)
2. Pricing (Anthropic, 9 Nov 2026)
3. Models overview (Anthropic, 9 Nov 2026)
4. Anthropic releases Claude Fable 5.2 and Claude Mythos 5.2 ahead of IPO (CNBC, 9 Nov 2026)