Claude Mythos Preview
claude-mythos-preview
About
Claude Mythos Preview is Anthropic's frontier research model, positioned above the public Claude 4 family and released exclusively via invitation-only Project Glasswing to roughly 12 launch partners and over 40 organizations working on critical infrastructure. No public API or self-serve access. Specializes in defensive cybersecurity — autonomously identified zero-day vulnerabilities including a 27-year-old OpenBSD TCP SACK remote code execution bug and a 17-year-old FreeBSD NFS RCE. Codenamed Capybara internally. Scores 93.9% on SWE-bench Verified, 82.0% on Terminal-Bench 2.0, and 97.6% on USAMO 2026. Partner pricing: $25/$125 per million tokens (input/output). Max output: 128K tokens. Knowledge cutoff: December 2025.
Claude Mythos Preview has a 1M-token context window.
Capabilities
Benchmark Scores(1)
| Benchmark | Score | Version | Source |
|---|---|---|---|
| SWE-bench Verified | 93.9 | SWE-bench Verified | https://red.anthropic.com/2026/mythos-preview/ |
Specifications
Created by
Developing safe and ethical AI systems.