# Vercel: Computer use CLI for AI agents

> Source: <https://agent-browser.dev/desktop>
> Published: 2026-11-03 05:26:34+00:00

# agent-desktop

agent-desktop reads the accessibility tree of a desktop app and returns it as JSON. Every element an agent can act on gets a ref. The agent acts on a ref, reads the UI again to check the result, and repeats. It ships as a CLI and as a C library for macOS, Windows, and Linux.

## [What agent-desktop is and is not](#what-agent-desktop-is-and-is-not)

- **A tool that agents call.** It is not an agent. The observe, act, and verify loop lives in the calling agent or script.
- **No model inside.** It never embeds an LLM, has no GUI, and has no interactive prompt. Every command prints one JSON envelope and exits.
- **Desktop apps only.** It does not automate web pages; use[agent-browser](https://agent-browser.dev/) for those. For the web contents of a Chromium or Electron app you launch, agent-desktop opens a DevTools port that agent-browser connects to. See[Chromium and Electron apps](https://agent-browser.dev/desktop/guides/chromium-and-electron) .
- **Limited to what apps expose.** It reads accessibility trees and does not match pixels, so it cannot see a UI that publishes no accessibility tree.

## [The loop in four commands](#the-loop-in-four-commands)

An agent maps an app, drills into the region it needs, acts on a ref, and checks the result.

Refs carry the id of the snapshot that produced them (`@s2txcl95uvubmn:e11`). [Snapshots and refs](https://agent-browser.dev/desktop/snapshots-and-refs) defines them, and [Skeleton and drill-down](https://agent-browser.dev/desktop/skeleton-and-drill-down) explains the first two commands. A successful action does not prove the UI changed, so the loop ends with a read. The [quick start](https://agent-browser.dev/desktop/quick-start) runs these commands with their output.

## [How it works](#how-it-works)

The same chain in text, from the caller to the app:

1. The calling agent: your code or an LLM loop. It runs a command and reads the JSON envelope it prints.
2. The `agent-desktop` CLI, or the[C library](https://agent-browser.dev/desktop/ffi) when you call it in process.
3. `agent-desktop-core` : the commands,`RefStore` , and snapshot building. Core defines the`PlatformAdapter` trait and every shared type.
4. `PlatformAdapter` , the only way core reaches an operating system.
5. One platform crate: `agent-desktop-macos` ,`agent-desktop-windows` , or`agent-desktop-linux` .
6. The OS accessibility API: the AX API on macOS, UI Automation on Windows, AT-SPI on Linux.
7. The app, which exposes its UI through that API.

Core never imports a platform crate, and platform crates never import each other. Only the CLI and the C library connect a platform crate to core, and each picks it at compile time, so a binary drives the OS it was built for.

## [Platform support](#platform-support)

| Platform | Requirement | Accessibility API | 
|---|---|---|
| [macOS](https://agent-browser.dev/desktop/platforms/macos) | macOS 13 or later, Intel or Apple Silicon. Accessibility permission for the app that runs agent-desktop. | AX API | 
| [Windows](https://agent-browser.dev/desktop/platforms/windows) | Windows 10 1809 or later, or Windows Server 2019 or later, on x64 or ARM64, in the signed-in user's interactive desktop. | UI Automation | 
| [Linux](https://agent-browser.dev/desktop/platforms/linux) | Ubuntu 24.04 or later on x86_64 or aarch64 (glibc 2.35 floor), in the user's graphical session with a running AT-SPI bus. | AT-SPI | 

The CLI has the same 60 command names on every platform. Four of them (`key-down`, `key-up`, `mouse-down`, `mouse-up`) fail closed everywhere. Each platform page lists what works headless, what needs `--headed`, and what refuses.

## [Next steps](#next-steps)

- [Installation](https://agent-browser.dev/desktop/installation) : install the CLI, verify it, and grant permissions.
- [Quick start](https://agent-browser.dev/desktop/quick-start) : one complete run against a real app.
- [Skills](https://agent-browser.dev/desktop/skills) : the guides your agent reads before it acts.
- [Commands](https://agent-browser.dev/desktop/commands) : all 60 commands.