GitHub Copilot weekly releases: Claude Haiku 5.5, local sandboxing GA

GitHub's weekly Copilot roundup, published October 9, 2026, lists:

• Claude Haiku 5.5 is available to Copilot Pro, Pro+, Max, Business and Enterprise users.
• Local sandboxing is generally available in Copilot CLI, the Copilot app and VS Code sessions using Agent Host, limiting agents' access to files, networks and credentials. GitHub says it is included at no extra cost.
• Copilot app: separate GitHub accounts can be used for the Copilot license and for repositories.
• Copilot CLI: /model can discover models from a running local Ollama instance.
• VS Code 1.141: agent sessions can be viewed side by side in the Agents window, and chat has an "Open worktree cleanup" action for inactive session worktrees.