Fable 5.1
#1 in OtherUnknown · v5.1 · 14× · last seen Sep 06, 2026
100
Momentum
Claude Fable 5.1 is Anthropic's most advanced AI model (Mythos-class), released on September 1, 2026 as the successor to Fable 5. It is designed for long-running, complex tasks in software development, scientific research, and knowledge work, and supports text and image inputs. The model is available through Claude Apps (Pro, Max, Team, Enterprise), the Claude API, and via AWS, Google Cloud, and Microsoft Foundry. An identically configured model with reduced safety requirements called Claude Mythos 5.1 is aimed at trusted partners in cybersecurity and biosciences.
Momentum trend
08.06.06.09.
Features
| License | Proprietary Anthropic model, access via paid API/subscription; designated a 'Covered Model' with additional safety and access policies |
| Platform | Claude apps (Pro, Max, Team, Enterprise), Claude API, AWS (Bedrock & Claude Platform), Google Cloud, Microsoft Foundry |
| Price | $10 per million input tokens / $50 per million output tokens; cache reads $0.25 per million tokens |
| Release Date | September 1, 2026 |