Sandcat

Sandcat

Sandcat is a Docker & [dev container](https://containers.dev) setup for securely running AI agents. The environment is sandboxed, with controlled network access and transparent secret substitution. All of this is done while retaining the convenience of working in an IDE like VS Code.

All container traffic is routed through a transparent [mitmproxy](https://mitmproxy.org/) via WireGuard, capturing HTTP/S, DNS, and all other TCP/UDP traffic without per-tool proxy configuration. A straightforward allow/deny list-based engine controls which network requests go through, and a secret substitution system injects credentials at the proxy level so the container never sees real values.

This repository contains:

• a bash CLI to initialize the sandbox for a project, copying and customizing the necessary files (see cli/)
• reusable proxy definitions under cli/templates/devcontainer/sandcat/: Dockerfile.wg-client, compose-proxy.yml, and scripts/ that perform the network filtering & secret substitution
• template application and dev container configuration under cli/templates/devcontainer/: Dockerfile.app, compose-all.yml, devcontainer.json. This should be fine-tuned for each project and specific development stack, to install required tools and dependencies.

Sandcat can be used as a devcontainer setup, or standalone, providing a shell for secure development.

Sandcat is part of [Visdom](https://virtuslab.com/services/visdom), VirtusLab's AI-driven software delivery infrastructure.

Quick start

1. Install sandcat CLI

The [CLI](cli/README.md) is a helper script and thin wrapper around docker-compose that simplifies the process of initializing and starting the sandbox.

It has two main tasks:

• copy the necessary configuration files from the cli/templates directory into your project and customize them based on your choices (development stack, etc.)
• run docker compose commands with the correct compose file automatical