Offscreen

Offscreen is a macOS development tool that runs AI coding agent UI tests and GUI apps in throwaway virtual machines.

Offscreen isolates AI coding agents by running UI tests, the iOS Simulator, and GUI apps in fresh macOS virtual machines instead of your own desktop. It consists of a CLI, daemon, and menu bar app that manage a shared job queue, returning logs, screenshots, and .xcresult bundles. Designed for developers using Apple silicon Macs with macOS 14 or later, it prevents agents from hijacking window focus and stealing input while executing tests. The tool supports custom task configurations via TOML files, one-off commands, and a host lane for tasks requiring physical hardware when you are away. It builds on Tart to handle VM cloning, artifact collection, and cleanup automatically.

Offscreen at a glance

Best for: Software engineer
Runs on: macOS, CLI
Pricing: Free
Released: October 2026
Category: AI agent tool
Website: github.com/markphelps/offscreen

Key features

Run macOS UI tests and XCUITest in fresh VMs
Boot and test against the iOS Simulator
Capture screenshots and .xcresult bundles automatically
Queue jobs from multiple agents and scripts
Manage tasks with a menu bar app and CLI
Run one-off commands in isolated virtual machines
Configure tasks using project contract TOML files

Use it for

Running automated UI tests without losing desktop focus
Testing iOS applications in the simulator via agents
Capturing screenshots of newly built apps for agent review
Executing one-off shell commands in clean environments

Alternatives to Offscreen

offstage — Keeps coding agent simulators and windows off your main desktop display.
barn — Monitors multiple AI coding agents on your Mac and jumps to the exact tab when needed.
Mac Computer Use — Enables local desktop automation through native Mac windows and Accessibility controls.
AgentDock — Manages multiple coding agents from one screen-edge inbox without switching tabs.
Yomado — Enables visual agents to work in desktop apps without requiring app-specific MCPs.
Glitchrupt — Provides rapid visual and audio cues on macOS when an AI agent requires input.
agent-device — Token-efficient snapshots and semantic references for native mobile and TV apps.
Peekaboo — Enables AI agents to interact with macOS applications directly.
Mecum — Runs agents in desktop apps on a virtual display without virtual machines.
Simulator Use — It runs tests and reads screens fast with a token-efficient native engine.
Twine — Coordinates multiple coding agents with visual traces and controlled workflows.
iphone-use — Operates real iPhones via HTTP and MCP without touching the host screen.

All Offscreen alternatives