Claude Fable 5.1 Reaches General Availability in GitHub Copilot
Anthropic’s Claude Fable 5.1 — the latest model in its Mythos class — is now generally available in GitHub Copilot, positioned for long-horizon, autonomous coding and knowledge-work tasks.
Details
- Strengths cited: internal testing showed strong results on deep codebase research, feature development, and complex agentic workflows
- Data retention note: unlike other Claude models in Copilot, Fable 5.1 requires data retention by default for safety monitoring, though eligible enterprise customers can get zero data retention through the end of the year
- Where it’s available: across 10 surfaces, including Visual Studio Code, Visual Studio, JetBrains IDEs, Xcode, GitHub.com, Copilot CLI, and mobile apps on iOS and Android
- Who can use it: Copilot Pro+, Max, Business, and Enterprise subscribers, with administrators needing to explicitly enable the model in settings before it appears
- Pricing: billed at provider list pricing under Copilot’s usage-based billing model
What happened next
Fable 5.1’s GA rollout gives Copilot users across nearly every major surface access to Anthropic’s newest Mythos-class model on day one of general availability, continuing GitHub’s pattern of fast-following new frontier model releases from multiple providers rather than favoring a single model family.