Masterblaster

Masterblaster - `mb`

Create, manage, and orchestrate AI agents sandboxes.

Masterblaster boots [stereOS](https://stereos.ai) machines - a NixOS-based Linux distribution purpose-built for AI agents - and manages their full lifecycle: image pulling, machine creation, secret injection, shared directory mounting, and agent orchestration.

Sandboxes are ephemeral, isolated, reproducible, and focused on security.

Install

curl -fsSL https://mb.stereos.ai/install | bash

Quick start

1. Pull a mixtape

Mixtapes are pre-built stereOS images bundled with AI agent harnesses. Pull one from the registry:

mb pull opencode-mixtape

2. Create a jcard

A `jcard.toml` file defines your sandbox configuration. Run `mb init` to generate one, or create it by hand:

# jcard.toml

mixtape = "opencode-mixtape:latest"

[resources]
cpus   = 1
memory = "4GiB"
disk   = "40GiB"

[network]
mode = "nat"

[[shared]]
host  = "./"
guest = "/home/agent/workspace"

[secrets]
ANTHROPIC_API_KEY = "${ANTHROPIC_API_KEY}"

[agent]
harness = "opencode"
prompt  = "review the code in this directory and fix any failing tests"
workdir = "/home/agent/workspace"
restart = "on-failure"

3. Launch

mb up            # Create sandbox from jcard.tomlmb ssh my-sandbox
mb ssh           # SSH into a running sandbox
mb list          # List all sandboxes
mb status        # Check sandbox status
mb down          # Graceful shutdown
mb destroy       # Remove sandbox and all resources

jcard.toml reference

The jcard is the single configuration file for a sandbox. Most fields are optional and defaults are applied automatically.

Section	Field	Default	Description
(top)	mixtape	"base:latest"	Mixtape image in name:tag format
(top)	mixtape_digest		Pin to an exact OCI digest