Anthropic announced Claude Fable 5.2 and Claude Mythos 5.2 on November 9, 2026. Anthropic describes them as its most capable models for demanding technical work.
What to know
- One model, two access levels: Anthropic says the two are the same underlying model. Fable adds stronger cybersecurity and biology safeguards so it can be offered to all users. Mythos is more capable in those areas but restricted to vetted users.
- Price: Anthropic lists $8 per million input tokens and $40 per million output tokens. Optional fast mode, up to 2.5 times faster generation, is $16 and $80.
- Speed: Anthropic says outputs are up to 30% faster than Fable 5.1 and Mythos 5.1.
- Where: Fable 5.2 uses the API model ID
claude-fable-5-2and is available on all platforms, including Amazon Web Services, Google Cloud and Microsoft Azure. Mythos 5.2 is limited to organizations in Anthropic’s Cyber Verification Program and Life Sciences Verification Program. - Safeguards: Anthropic says Fable 5.2’s classifiers block high-risk cyber activity such as penetration testing and exploit generation, and most research biology tasks. It reports about 55% fewer blocks than Fable 5.1. Blocked cyber queries get an answer from Opus 4.8 and blocked biology queries from Opus 5.
- Plans: Anthropic says eligible paid subscribers get extra Fable usage this week, and Fable is included for up to 50% of weekly usage limits on Pro plans and standard Team seats.
- Benchmarks: these are Anthropic’s own figures. For example, it lists FrontierSWE v2 at 69.9% for Fable 5.2, against 62.3% for Opus 5.5, and Remote Labor Index at 41.3% against 21.3%. On the same table Gemini 4 Carbon scores higher on AutomationBench (53.9% vs 51.4%). Anthropic’s Elo table shows Opus 5.5 at 1800 and Fable 5.2 at 1785. Treat vendor benchmarks as a starting point and test on your own tasks.
Why it matters
Fable 5.2 sits above the 5.5 tiers on price, at twice Opus 5.5’s listed rate. Whether it is worth it depends on the job; our Claude 5.5 model chooser covers the cheaper tiers. Background in the Opus 5.5 summary, the Claude page and the model tracker.
Disclosure: Anthropic’s Claude is one of the tools used to help build this site. We cover Claude models on the same basis as every other maker.
Source: Anthropic. We summarise in our own words; check the source for the full details.