agents / copilot

Stonewall for GitHub Copilot CLI

Stonewall runs GitHub Copilot CLI inside a kernel-enforced sandbox. The agent only sees your project directory and the few binaries and paths the policy names. Everything else on your machine, from ~/.ssh to your browser profile, is invisible to it, no matter what a prompt says.

Policy

For GitHub Copilot CLI, stonewall.sh provides a specific policy at https://stonewall.sh/policies/copilot.yml. You can use it by simply including it in your .stonewall.yml config, or using the CLI:

stonewall policy include https://stonewall.sh/policies/copilot.yml

It covers only what GitHub Copilot CLI needs to start and authenticate:

• Binaries: copilot and node (the runtime of the npm launcher; the Homebrew and install-script builds are native binaries and do not use it).
• Writable paths: ~/.copilot (settings, login state, sessions, logs, MCP and plugin data) and ~/.cache/copilot / ~/Library/Caches/copilot (the cache directory on Linux / macOS).

It intentionally does not allow sh, bash, git or any other tool the agent could use to run arbitrary programs.

Related Policies

The GitHub Copilot CLI policy is meant to be combined with policies for what your project actually needs:

• base.yml: read-only file inspection (cat, grep, ls, …), hides .env and secrets.
• git-safe.yml: read-only git, no commits, no credentials.
• git-unsafe.yml: full git, including commits and push.
• A language policy for builds and tests, e.g. go.yml, python.yml or typescript.yml.

Usage

Start the agent through stonewall instead of directly:

stonewall copilot

Or alias it in your bash / zsh profile:

alias copilot="stonewall copilot"