Claude Fable 5 is Generally Available for GitHub Copilot

GitHub Copilot has announced the general availability of Anthropic's Claude Fable 5, a cutting-edge Mythos-class AI model, for its users. This integration is poised to transform how developers interact with AI in their coding workflows, particularly for intricate and extended autonomous tasks. Claude Fable 5 is specifically designed to handle complex coding challenges and knowledge-intensive work, offering a more streamlined and efficient experience. Internal benchmarks conducted by GitHub indicate that Claude Fable 5 outperforms previous Opus-tier models in autonomous coding workflows. It achieves equivalent results with fewer tool calls and a lower consumption of tokens, which translates to potentially more cost-effective and faster AI-assisted development. This efficiency is a key benefit for developers tackling large-scale projects or requiring extensive AI support. The new model is broadly accessible to a significant portion of the GitHub Copilot user base, including those on Pro+, Max, Business, and Enterprise plans. Developers can leverage Claude Fable 5 across various platforms and interfaces where GitHub Copilot is available. This includes popular integrated development environments (IDEs) like Visual Studio Code and Visual Studio, as well as the Copilot Command Line Interface (CLI), the GitHub Copilot cloud agent, the dedicated GitHub Copilot app, github.com, GitHub Mobile for iOS and Android, JetBrains IDEs, Xcode, and Eclipse. The rollout will be gradual, ensuring a smooth transition for all users. However, a crucial detail accompanying the release of Claude Fable 5 is its data retention policy. Unlike other Claude models integrated with GitHub Copilot, such as Claude Opus 4.8, Sonnet 4.5, and Haiku 4.5, which adhere to a Zero Data Retention (ZDR) policy, Claude Fable 5 requires data retention. Anthropic will retain prompts and outputs for up to 30 days. This retention is exclusively for the purpose of operating safety classifiers that detect harmful or abusive use, and the retained data will not be used to train Anthropic's models. This policy necessitates that Copilot Enterprise and Business plan administrators enable the Claude Fable 5 policy in their Copilot settings, acknowledging this data retention requirement. This move signifies GitHub's continuous effort to enhance its AI-powered development tools by integrating advanced models, providing developers with more powerful capabilities for code generation, problem-solving, and overall software development lifecycle management. The introduction of Claude Fable 5 aims to further empower developers to automate and accelerate their work, pushing the boundaries of agentic development.