GitHub Copilot App Adds Local Sandboxing for Agent Sessions

GitHub [released local sandboxing for the Copilot app](https://github.blog/changelog/2026-09-23-local-sandboxing-in-the-github-copilot-app/) on September 23. The public preview lets developers set limits on what an agent can access when it runs in a local repository or working tree session. It is off by default. The controls live in each project's settings. Developers can add folders where the agent may read and write, folders it may only read, and folders it cannot access. Separate settings govern outbound internet access, local network access, Git credentials for authenticated HTTPS operations, and GitHub CLI credentials. That separation matters when a coding agent runs shell commands. A project may need access to its repository and package registry without also needing access to other folders or credentials on the machine. The settings define the policy the app requests when a sandboxed session starts. GitHub says enterprise-managed settings can make the effective policy more restrictive. If the operating system cannot enforce the requested policy, the sandboxed shell fails instead of running without a sandbox. ## How to turn it on Open the Copilot app's settings, select a project, and enable **Sandbox new sessions** under Sandbox. The default applies to new sessions only. For an active local session, enter `/sandbox on`. Changes to file, network, or credential settings take effect when a new session starts or an existing one restarts, according to [GitHub's release note](https://github.blog/changelog/2026-09-23-local-sandboxing-in-the-github-copilot-app/). The feature covers local repository and working tree sessions in the Copilot app. It does not cover cloud sandbox sessions or sessions on remote hosts. The Copilot app and Copilot CLI also have separate sandbox settings, so changing one does not configure the other. GitHub labels local sandboxing a public preview, with details subject to change.