Claude Fable 5
Claude Fable 5 is the earlier Fable release for extended reasoning. It remains active in Anthropic’s API catalog, with Fable 5.1 now the current version.
Fable and Mythos use different access routes
Mythos 5 offers the same underlying model through a verified defensive-security route. Fable 5 has the same listed context, output limit and token prices. The distinction is access and intended use, not a larger Mythos parameter count.Claude Fable 5 model reference
Specifications & access
| Detail | Value and conditions |
|---|---|
| Launch date | |
| Access | API |
| Model identifiers | claude-fable-5 |
| Context window | 1,000,000 tokens Direct Claude API context limit Claude Fable 5 model reference |
| Maximum output | 128,000 tokens Synchronous Messages API maximum Claude Fable 5 model reference |
| Input price | 10 USD per million tokens Standard direct API input; cache, batch and tool charges are separate Claude Fable 5 model reference |
| Output price | 50 USD per million tokens Standard direct API output Claude Fable 5 model reference |
| Input and output | Text and images in; text outClaude Fable 5 model reference |
| Reasoning control | Adaptive thinking is always on; default effort is high.Claude Fable 5 model reference |
| Reliable knowledge cutoff | January 2026Claude Fable 5 model reference |
Related models
- Claude Fable 5.1
Anthropic · Claude Fable
A reasoning model for complex tasks and work that spans many steps.
Launch date API - Claude Mythos 5
Anthropic · Claude Mythos
Claude Mythos 5 is the verified-access offering of Claude Fable 5 for defensive cybersecurity.
Launch date Restricted accessAPI