GitHub announced Claude Fable 5.1, Anthropic’s latest Mythos-class model, is generally available in GitHub Copilot. Internal testing highlighted long-running coding, deep codebase research, and complex agentic workflows, and it is selectable in the Copilot app, CLI, and VS Code (@code).

Key Takeaways

  • ✓Claude Fable 5.1 is GA in GitHub Copilot, not preview-only.
  • ✓GitHub highlights long-running coding, codebase research, and agentic workflows.
  • ✓Available across Copilot App, CLI, and VS Code for existing Copilot setups.
⚡

Key Decision Metrics at a Glance

TL;DR Verdict
🏆 Benchmark RankRank
See how it ranks on the leaderboard
Full Leaderboard→
💰 Cost & PlansCompare
in: $3 / out: $15
Compare Plans↗
🛠️ Ecosystem & IDERules
Claude Code (Anthropic)
Setup IDE Rules↗
🧭

Heavy Claude Code use: compare subscription limits and API bills

Compare 40 dev plans & simulate token costs vs $20/mo subscriptions

⚔️ Compare Model→💰 Compare plans & limits↗
Action HubReady to adopt this in production?

Benchmark side-by-side against alternatives, or calculate monthly token cost vs subscription break-even.

⚔️ Launch VS Compare→💳 View Plans↗
Up NextAnthropic tightens Messages API: no pre-thinking edits on new Fable 5.1 accounts
Read Now→