Anthropic Sandbox Runtime vs Firejail

Anthropic Sandbox Runtime (srt) is a free, open-source research preview that applies filesystem and network restrictions to processes at the operating-system level, without requiring a container. It can be used as a CLI tool or library to sandbox agents, local MCP servers, bash commands and other processes. Filesystem writes and network access are denied by default, with configuration options to allow paths and domains. The project documents macOS, Linux and Windows support, using sandbox-exec, bubblewrap or a dedicated local sandbox account with Windows Filtering Platform and filesystem ACLs, respectively. Windows is marked alpha. Install it from npm with `npm install -g @anthropic-ai/sandbox-runtime`. Linux requires bubblewrap, socat and ripgrep; macOS requires ripgrep, and Windows needs a one-time elevated setup step. On macOS, srt can provide real-time alerts from the system sandbox violation log. Linux bubblewrap has no built-in violation reporting, and Linux network filtering relies on proxy environment variables, which some programs may ignore. The preview is developed for Claude Code; its APIs and configuration formats may evolve.

Firejail is a free, self-hosted Linux sandboxing program for restricting untrusted applications, servers, graphical programs, and login sessions. It uses Linux namespaces and seccomp-bpf so sandboxed processes receive private views of network, process, and mount tables. The software runs on Linux computers with a 3.x kernel or newer. Security controls include protocol filtering, noroot user namespaces, Linux capabilities, D-BUS filtering, and optional AppArmor or SELinux support. Mandatory Access Control can block more than 1,000 desktop applications from passwords, encryption keys, and private data, with more than 1,000 profiles available in /etc/firejail. Firejail can create an isolated TCP/IP stack with routing, firewall, and interfaces, and nettrace can inspect traffic. AppImage packages are supported. Firetools adds a Qt5 graphical launcher, tray integration, editing, management, and statistics; FDNS provides DNS-over-HTTPS through non-logging providers. Running sudo firecfg integrates application menus and file-manager launches. The project targets home users and Linux beginners rather than enterprise customers.