Updated November 12, 2026.
Anthropic released Claude Fable 5.2 and Claude Mythos 5.2 on November 9, bringing a new generation of frontier Claude models for coding, research and advanced technical work.
Claude Fable 5.2 and Mythos 5.2 at a glance
- Context window: 1 million tokens
- Maximum output: 128,000 tokens
- Input price: $8 per million tokens
- Output price: $40 per million tokens
- Adaptive thinking: always on
What is the difference between Fable and Mythos?
Anthropic says Fable and Mythos use the same underlying model. Fable includes stronger safeguards for cybersecurity and biology tasks and is generally available. Mythos exposes more advanced capabilities for vetted organizations and approved partners.
What improved in Fable 5.2?
Anthropic highlights gains in coding, reasoning and vision. The company says internal teams used versions of Fable 5.2 for difficult software migrations, including moving a critical service from Python to Rust, as well as an experimental operating-system project coordinated by more than 1,000 subagents.
What improved in Mythos 5.2?
Mythos 5.2 is positioned as Anthropic’s most capable cybersecurity engineering model. Anthropic reports improved vulnerability discovery compared with Mythos 5.1 and Opus 5.5.
Availability
Claude Fable 5.2 is generally available through Anthropic’s Claude products and supported cloud platforms. Claude Mythos 5.2 remains limited to approved organizations and programs.
