Claude Haiku 5.5 Reaches General Availability in GitHub Copilot

GitHub made Claude Haiku 5.5, the newest lightweight model from Anthropic, generally available in Copilot, according to its October 7 changelog. It reaches Copilot Pro, Pro+, Max, Business and Enterprise users through the model picker in VS Code, Visual Studio, JetBrains IDEs, Xcode, Eclipse, Copilot CLI, the Copilot cloud agent, the Copilot app, github.com and GitHub Mobile, with a gradual rollout. It is billed at the provider's list price under usage-based billing. For Business and Enterprise, administrators control access through Copilot's model policy, and new models are switched on by default unless an admin has turned that default off or blocked this model.

GitHub pitches it for fast, high-volume work such as subagents, the helper agents a main agent hands narrow jobs, along with quick edits and terminal tasks, which echoes how Anthropic's own launch frames it for high-volume, cost-sensitive tasks. The one performance claim is that in GitHub's early testing Haiku 5.5 matched Claude Sonnet 5 on many coding tasks while using significantly fewer tokens and steps. The changelog names no tasks, scores or token counts, so the claim cannot be checked from it. Cognition made a similar vendor-reported comparison when adding the model to Devin, saying it scored 58.4% on FrontierCode 1.1, ahead of Sonnet 5 at about an eighth of the cost per task; that is a different test run by a different company, not confirmation of GitHub's numbers.