GitHub made Claude Haiku 5.5 generally available in GitHub Copilot on October 7, 2026. The changelog entry positions Anthropic's lightweight model for fast, high-volume work such as subagents, quick edits and terminal tasks, and says that in early testing it matched Claude Sonnet 5 on many coding tasks while using significantly fewer tokens and steps. The announcement page carries a date without a time of day. Read the changelog entry.
Where it is available
Haiku 5.5 is offered to Copilot Pro, Pro+, Max, Business and Enterprise users — a wider plan range than the Gemini 4 Argon rollout, which started at Pro+. The model can be selected in the picker in Visual Studio Code, Visual Studio, Copilot CLI, the GitHub Copilot cloud agent, the Copilot app, github.com, GitHub Mobile on iOS and Android, JetBrains IDEs, Xcode and Eclipse. Rollout is gradual, so the model may not appear for every account immediately.
Billing and administration
- The model is billed at provider list pricing under usage-based billing, per GitHub's models-and-pricing documentation.
- Copilot Enterprise and Business administrators manage access through the model policy in Copilot settings; new models are enabled by default unless the global default was turned off or the model is explicitly disabled.
The Sonnet 5 comparison comes from GitHub's early testing rather than an independent benchmark. For the model's own launch and API rates, see our October launch report; the GitHub Copilot profile lists official entry points, and the Claude profile covers the model family.
