box by ASCII

Persistent Linux VM sandbox for AI agents

Real software work is messy. Agents install dependencies, run builds, start services, inspect logs, and retry. A persistent Linux VM gives them a stable place to do that work.

box turns each agent workspace into a full Ubuntu machine instead of a narrow runtime wrapper.

What you get

Ubuntu VM per workspace

Persistent filesystem and process environment

SSH access for humans and agents

Docker support for multi-service apps

Dedicated IPv4 for reachable previews and services

Why persistence matters

Agents lose time when every task starts from a cold, empty environment. Persistent VMs keep repo checkouts, installed packages, caches, build artifacts, service logs, and debugging context available between steps.

Full-machine capabilities

A box VM supports SSH, Docker inside the VM, language runtimes, GitHub CLI, and normal Linux tooling. That means agents can run ordinary engineering workflows instead of adapting every task to a restricted sandbox API.

Branch, parallelize, and recover

Agent work benefits from machine-level branching. Fork a VM for a new attempt, run agents in parallel, compare outputs, and keep useful state without rebuilding the world each time.

Start a box VM

Install the CLI, create a machine, and run your agent in a full Linux environment.

curl -fsSL https://ascii.dev/api/box/install | sh