Claude Mythos 5
Claude Mythos 5 is the verified-access offering of Claude Fable 5 for defensive cybersecurity. Its API identifier is separate, but Anthropic describes it as the same model.
Restricted access
Verification controls access
Organizations must qualify through an Anthropic verification program, such as the Cyber Verification Program. An ordinary Claude API account does not establish access. Mythos 5.1 is the current Mythos release; the version 5 entry remains active in the lifecycle list.Claude Mythos 5 model reference
Specifications & access
| Detail | Value and conditions |
|---|---|
| Status | Restricted access |
| Launch date | |
| Access | API |
| Model identifiers | claude-mythos-5 |
| Context window | 1,000,000 tokens Direct Claude API context limit Claude Mythos 5 model reference |
| Maximum output | 128,000 tokens Synchronous Messages API maximum Claude Mythos 5 model reference |
| Input price | 10 USD per million tokens Standard direct API input; cache, batch and tool charges are separate Claude Mythos 5 model reference |
| Output price | 50 USD per million tokens Standard direct API output Claude Mythos 5 model reference |
| Input and output | Text and images in; text outClaude Mythos 5 model reference |
| Reasoning control | Adaptive thinking is always on; default effort is high.Claude Mythos 5 model reference |
| Reliable knowledge cutoff | January 2026Claude Mythos 5 model reference |
| Access condition | Anthropic verification is required for the organization.Claude Mythos 5 model reference |
Related models
- Claude Fable 5
Anthropic · Claude Fable
Claude Fable 5 is the earlier Fable release for extended reasoning.
Launch date API - Claude Mythos 5.1
Anthropic · Claude Mythos
Claude Mythos 5.1 gives verified organizations access to the Fable 5.1 model for defensive cybersecurity.
Launch date Restricted accessAPI