Claude Mythos 5.2

// Overview

Claude Mythos 5.2 is the restricted-access half of Anthropic's 9 November 2026 Mythos-class release. It is the same underlying model as Claude Fable 5.2 without certain cybersecurity and biology safeguards, and Anthropic offers it only to organizations verified through its verification programs: cybersecurity professionals apply through the Cyber Verification Program and life-sciences researchers through the Life Sciences Verification Program. Claude Enterprise customers can also use it inside Claude Security without joining the Cyber Verification Program.

It shares Claude Fable 5.2's specifications and pricing: a 1M-token context window, up to 128K output tokens, text and image input, adaptive thinking that is always on with a default effort of high, and a June 2026 reliable knowledge cutoff. Standard pricing is $8 per million input tokens and $40 per million output tokens, with cache reads at $0.20 per million. The API model ID is claude-mythos-5-2, and it is offered on the Claude API, Amazon Bedrock, Claude Models on Google Cloud and Microsoft Foundry. Anthropic says output is up to 30% faster than Claude Fable 5.1 and Claude Mythos 5.1.

Anthropic reports Claude Mythos 5.2 at 89.6% on CVE Rediscovery against 78.3% for Mythos 5.1, at 76.3% on CyScenarioBench against 61.7% for Mythos 5.1, and at 85.1% on 24-hour de novo binder design against 79.1% for Mythos 5.1. In one tester's audit it found 10.2% more vulnerabilities than Claude Opus 5.5 and 14.4% more than Claude Mythos 5.1, and Anthropic reports that it accurately modeled 28 of the 34 virus capsid structures it attempted.

// Benchmarks

This model's scores

1. CVE Rediscovery (cybersecurity)89.6%
2. De novo binder design, 24 hr (protein design)85.1%
3. CyScenarioBench (cybersecurity)76.3%
4. Terminal-Bench-Science 0.175.3%

Scores on a 0–100 scale (25-point gridlines); higher is better. Each benchmark links to its published source.

// Pricing

Same specifications and pricing as Claude Fable 5.2; Batch API 50% off.

Pricing source ↗

// Strengths

• Same model as Claude Fable 5.2 with safeguards loosened for verified cybersecurity and life-sciences work
• 89.6% on CVE Rediscovery, up from 78.3% for Claude Mythos 5.1
• 76.3% on CyScenarioBench, up from 61.7% for Claude Mythos 5.1
• 85.1% on 24-hour de novo binder design, up from 79.1% for Claude Mythos 5.1
• 1M-token context window and 128K max output at Claude Fable 5.2's $8/$40 per MTok pricing

// Best for

• Find and rediscover software vulnerabilities for defensive security work inside a verified organization.
• Support life-sciences research such as protein binder design and capsid structure prediction where general-availability safeguards would block the work.
• Use it in Claude Security on Claude Enterprise for vulnerability scanning without a separate Cyber Verification Program enrollment.
• Move from Claude Mythos 5.1 at a lower per-token price once your verification programme grants access.

// How to access

// Claude Fable / Mythos (Mythos-class) — every version

The full lineage of the Claude Fable / Mythos (Mythos-class) line, newest first. Every version has its own page — click any to compare specs, benchmarks and pricing.