landstrip

landstrip runs a command in an OS-level sandbox using Landlock LSM on Linux, Seatbelt on macOS, and LPAC AppContainer on Windows. It accepts the Anthropic Sandbox Runtime JSON subset as the policy.

Installation

npm

npm install --save-dev @jarkkojs/landstrip

npx landstrip -p policy.json cargo test

The npm package installs a small Node.js wrapper and a platform-specific native binary package.

Backends

Windows uses an AppContainer. The backend grants the generated AppContainer SID access to the lowered read and write roots, so Windows policies must use explicit read allowlists. Fine-grained TCP and Unix socket policies are rejected until Windows enforcement exists.

Network Policy

Sandbox mode denies direct network access by default. Proxy ports, local binding, and Unix sockets can be allowed with the Anthropic Sandbox Runtime network fields.

For a filesystem-only sandbox with unrestricted direct network access, set:

{
  "network": {
    "allowNetwork": true
  }
}

On Linux and macOS, allowNetwork disables landstrip network enforcement while leaving filesystem policy enforcement in place. Windows rejects unrestricted network policies until Windows network support exists.

Development

Commit messages

• <subsystem>: <message>
• Long description for non-trivial changes.
• Kernel style commit messages.
• Signed-off-by

Documenting errors

The following snippet demonstrates the recommended pattern for documenting the return values on error:

/// # Errors
///
/// Returns [`<variant's unqualified name>`](<variant's unqualified name>)
/// Returns ...

Licensing

The JavaScript npm wrapper is licensed under Apache-2.0. The Rust source and native binaries are licensed under LGPL-2.1-or-later.