# Mythos 5 (Claude Mythos 5)

Anthropic, released 2026-06-09

**Verdict: conditional.** The strongest cybersecurity model in the world (83.8% CyberGym), built on Fable 5's weights with safety classifiers lifted. Access was suspended after the Jun 12 export directive; partially restored Jun 26 to ~100 designated US critical-infrastructure organizations (Project Glasswing). Verdict stays CONDITIONAL: capability is elite, but access is gated by federal designation. Not a public API: usable only if your organization is on the Commerce Department list. Last verified 2026-10-19.

## Pricing

- Input: $10 / 1M tokens
- Output: $50 / 1M tokens
- Context: 1M tokens (restricted access)

## Strengths

- Cybersecurity vulnerability discovery and exploit reproduction — 83.8% on CyberGym, agentic hacking across reconnaissance, discovery, and lateral movement
- Protein design and drug discovery — accelerated design process ~10x vs human operators in internal Anthropic studies
- Novel scientific hypothesis generation — preferred ~80% over Opus-class models by scientists in blinded head-to-head molecular biology comparisons
- Autonomous multi-day research — conducted novel genomics research over 1+ weeks with only high-level human input
- General-purpose chat or development — restricted to Project Glasswing partners only, not a public API
- Budget or high-volume workloads — $50/1M output is premium pricing, and access is capped by invitation
- Users outside US/approved geographies — export control ban blocks all foreign national access, inside or outside the US

## Benchmarks

- CyberGym: 83.8% (https://www.axios.com/2026/06/23/white-house-openai-anthropic-safety-security)

## Sources

- [ClaudeFa.st — Fable 5 & Mythos 5 benchmarks](https://claudefa.st/blog/models/claude-fable-5-mythos-5)
- [Anthropic Claude Fable 5 and Mythos 5 announcement](https://www.anthropic.com/news/claude-fable-5-mythos-5)
- [Axios: White House quiet on OpenAI's Mythos-like model](https://www.axios.com/2026/06/23/white-house-openai-anthropic-safety-security)
- [Anthropic — Statement on US government directive](https://www.anthropic.com/news/fable-mythos-access)
- [WIRED — OpenAI Launches Full-Scale Effort to Patch Open-Source Bugs](https://www.wired.com/story/openai-launches-full-scale-effort-to-patch-open-source-bugs-as-it-takes-on-anthropics-mythos/)
- [CloudZero — Claude Mythos pricing 2026](https://www.cloudzero.com/blog/claude-mythos-pricing/)

Canonical: https://neomanex.com/models/mythos-5