Anthropic Launches Claude Fable 5.2 and Mythos 5.2 Models

Anthropic launches Claude Fable 5.2 and Mythos 5.2, faster and cheaper with big coding gains

Technology Desk | Wednesday, November 11, 2026, 05:35 IST

Anthropic Claude Fable 5.2 and Mythos 5.2 AI models launched

Anthropic launched Claude Fable 5.2 and Claude Mythos 5.2 on 10 November, with faster outputs and lower prices. (Photo: source article)

Anthropic has launched Claude Fable 5.2 and Claude Mythos 5.2, its latest AI models, promising faster outputs, lower prices and major gains in coding and cybersecurity work.

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Anthropic launched Claude Fable 5.2 and Claude Mythos 5.2 on Monday, 10 November 2026. Both models generate outputs up to 30 per cent faster than their 5.1 predecessors, and an optional fast mode is up to 2.5 times faster at double the price.

Pricing has been cut to $8 per million input tokens and $40 per million output tokens, down from $10 and $50. The fast mode takes the rates to $16 per million input tokens and $80 per million output tokens. The launch comes ahead of Anthropic's planned IPO and follows the Claude Haiku 5.5 rollout in October.

Fable 5.2 and the coding benchmark

Fable 5.2 scored 49.1 per cent on the FrontierCode 2.0 benchmark at Xhigh effort, against 32.4 per cent for Fable 5.1. Anthropic calls it the highest result among released models it has tested, a sharp jump in coding ability in a single generation.

In a demonstration, 1,000 Fable 5.2 agents built a working operating system prototype in nearly eight days. The experimental system included drivers, storage, windows, a login screen and an installer. The model also helped rewrite a software service from Python into Rust, and Anthropic says the rewritten service started around 26 times faster.

Fable 5.2 was also used to design three working electronic devices: a home voice-assistant hub, a USB speakerphone and a handheld virtual pet. The designs received manufacturing support from Diode. Its scientific capabilities were also tested, with 1,000 Fable agents converting an existing proof of Fermat's Last Theorem into a computer-checkable mathematical format in 30 hours.

Mythos 5.2 for cybersecurity

Mythos 5.2 is Anthropic's most capable model for cybersecurity engineering. It identified 89.6 per cent of vulnerabilities in an internal CVE Rediscovery evaluation, against 78.3 per cent for Mythos 5.1. Anthropic says it identified more software vulnerabilities than earlier models and accurately predicted the structures of 28 out of 34 virus protein shells tested.

Access to Mythos 5.2 is restricted to vetted cybersecurity and life-sciences organisations. Fable 5.2 is broadly available, including on AWS, Google Cloud and Microsoft Azure. Anthropic also says it has reduced unnecessary safety blocks by around 55 per cent compared with Fable 5.1 during early testing, and has strengthened safeguards against attempts to extract its models' capabilities through distillation.

For everyday coding and knowledge-based tasks, Anthropic continues to recommend Claude Opus 5.5, positioning Fable and Mythos for more demanding technical work. The two new models are aimed at researchers and developers tackling complex projects that previously required extensive time and resources.

Frequently Asked Questions (FAQs)

What is new in Claude Fable 5.2 and Mythos 5.2?

Both generate outputs up to 30 per cent faster than their 5.1 predecessors, with an optional fast mode up to 2.5 times faster, and prices cut to $8 per million input tokens and $40 per million output tokens.

How strong is Fable 5.2 at coding?

Fable 5.2 scored 49.1 per cent on the FrontierCode 2.0 benchmark at Xhigh effort, against 32.4 per cent for Fable 5.1, and 1,000 of its agents built a working operating system prototype in nearly eight days.

Who can use Mythos 5.2?

Mythos 5.2 access is restricted to vetted cybersecurity and life-sciences organisations, while Fable 5.2 is broadly available, including on AWS, Google Cloud and Microsoft Azure.