GitHub Copilot Integrates Claude Fable 5 for Autonomous Coding

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GitHub Copilot now offers Anthropic's Claude Fable 5, the first model in its Mythos class, for long-horizon, autonomous coding and knowledge-work tasks. This integration provides Copilot users with advanced agentic capabilities, enabling more efficient multi-step code resolution.

GitHub Copilot now integrates Anthropic's Claude Fable 5 for long-horizon, autonomous coding and knowledge-work. This model, the first in Anthropic's Mythos class, shows enhanced agentic capabilities, completing tasks with fewer tool calls and lower token consumption than previous Opus-tier models.
Availability
Copilot Pro+, Max, Business, Enterprise
Data Retention
30 days (for safety classifiers)
Policy Setting
Off by default for Business/Enterprise
Performance
Fewer tool calls, lower token consumption (vs. Opus-tier)
Model Class
Mythos class (first model)

This integration expands GitHub Copilot's capacity for complex, multi-step software engineering. Bringing a Mythos-class model directly into the Copilot stack moves enterprise developer tooling further into long-running, autonomous workflows.

Claude Fable 5 is available to Copilot Pro+, Max, Business, and Enterprise users in VS Code, Copilot CLI, and Copilot app. Administrators must enable its policy, off by default. Fable 5 requires 30-day data retention for Anthropic's safety classifiers, unlike other Claude models in Copilot.

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📣 Claude Fable 5, the first in @AnthropicAI's Mythos model class, is now generally available and rolling out in GitHub Copilot. It is designed for long-horizon, autonomous coding and knowledge-work tasks. Try it out in @code or the GitHub Copilot app. ⬇️ https://t.co/jJTqh35jjY https://t.co/tM3L1znxV2

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Still wondering? A few quick answers below.

Claude Fable 5 is Anthropic's first Mythos-class model, now integrated into GitHub Copilot. It is designed for long-horizon, autonomous coding and knowledge-work tasks, demonstrating enhanced agentic capabilities for multi-step problem-solving.

Claude Fable 5 is available to GitHub Copilot Pro+, Max, Business, and Enterprise users. For Business and Enterprise plans, administrators need to enable the Claude Fable 5 policy in Copilot settings, as it is off by default.

Yes, Claude Fable 5 requires data retention. Anthropic retains prompts and outputs for up to 30 days to operate safety classifiers. This data is used solely for detecting harmful or abusive use and is not used to train Anthropic's models.

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