Claude Mythos 5
Anthropic
The unsafeguarded sibling of Claude Fable 5 - the same underlying frontier model with safety classifiers lifted, offered only in limited availability to approved Project Glasswing cybersecurity partners. In Anthropic testing, Mythos autonomously found thousands of zero-day vulnerabilities and produced 181 working Firefox exploits on a harness where Opus 4.6 produced two.
Strengths
- Frontier Mythos-class capability with safeguards lifted for security research
- Autonomously found thousands of zero-day vulnerabilities in testing
- Produced 181 working Firefox exploits where Opus 4.6 produced two
- Shares Claude Fable 5's weights and 1M-token context window
Caveats
- Not generally available - limited to approved Project Glasswing partners
- Premium restricted pricing at $25/$125 per 1M tokens
- Unsafeguarded model intended only for vetted cybersecurity use
- Vendor
- Anthropic
- Context Window
- 1,000,000 tokens
- Max Output
- 128,000 tokens
- License
- Proprietary
- Release Date
- 2026-06-09
- Modalities
- textimage
Capabilities
Vision
Audio
Video
Tool Use
Resources
Pricing
$25 per 1M input tokens, $125 per 1M output tokens; restricted to approved Project Glasswing partners (not generally available).