Mythos
#68 in Frontier LLMsUnknown · since 7. April 2026 (Claude Mythos Preview); 9. Juni 2026 (Claude Mythos 5) · 10× · last seen Sep 02, 2026
Mythos (officially "Claude Mythos") is Anthropic's most powerful model line, first announced in April 2026 as "Claude Mythos Preview" and succeeded in June 2026 by "Claude Mythos 5". The model stands out for exceptional autonomous cybersecurity research, agentic coding, and complex reasoning capabilities, having identified thousands of previously unknown zero-day vulnerabilities. Due to high risks (cyber and bio capabilities), Mythos is not publicly available but restricted to the "Project Glasswing" partner program with select organizations and the US government, while a safeguarded variant ("Claude Fable 5") is offered publicly.
Features
| Key Benchmark (%) | SWE-bench Verified: 93.9% (Claude Mythos Preview) |
| Context Window (Tokens) | 1,000,000 tokens (1M), up to 128,000 output tokens |
| License | No public access; available only via Project Glasswing (invite-only partner program) and for US government organizations |
| Multimodality | General-purpose model with enhanced vision capabilities; supports adaptive reasoning/thinking |
| Platform | Anthropic API, Amazon Bedrock, Google Cloud Vertex AI/Gemini Enterprise Agent Platform (Project Glasswing partners only) |
| Price per 1M Tokens | Claude Mythos 5: $10 (input) / $50 (output); previously Mythos Preview: $25 (input) / $125 (output) |
| Release Date | Claude Mythos Preview: April 7, 2026; successor Claude Mythos 5: June 9, 2026 |