agent-browser

// Overview

agent-browser is an open-source browser automation tool from Vercel Labs, built for AI agents rather than for test scripts. It is a native Rust command-line program: an agent opens a page, reads it, clicks or types, and checks the result, one shell command at a time. Because every step is a plain command with text output, any coding agent that can run a terminal can use it, and an `agent-browser mcp` command also exposes it as an MCP server over stdio.

The core loop is built on snapshots. `agent-browser snapshot` returns the page as a compact accessibility tree with a ref such as `@e1` for each element, and the agent acts on those refs. Refs only hold for the page state they came from, so after a navigation or DOM change the agent takes a new snapshot. A click fails instead of reporting success when the target is hidden, disabled, off-screen or covered. CSS selectors, text, XPath and semantic locators work too.

Under the hood, the CLI sends each command to a background daemon that starts on the first command and controls the browser over the Chrome DevTools Protocol. Each `--session` gets its own daemon and browser, and a headless browser shuts down after an hour without commands. Chrome for Testing is the default; the tool can also attach to a running Chrome, use the Lightpanda or Obscura engines, drive Mobile Safari in the iOS Simulator, or connect to cloud browsers such as Browserbase, Browserless, Browser Use, Kernel and AgentCore. Its sibling project agent-desktop does the same for native desktop apps.

// What it does

• Accessibility-tree snapshots with a ref per element (`@e1`) that the agent acts on, then re-reads to verify
• Clicks fail loudly when the target is hidden, disabled, off-viewport or covered
• CSS, text, XPath and semantic locators, e.g. `find role button click --name "Submit"`
• Background daemon per session talking to the browser over the Chrome DevTools Protocol
• Chrome for Testing by default; attach to a running Chrome with `--cdp` or `--auto-connect`; Lightpanda and Obscura engines; Mobile Safari in the iOS Simulator
• Cloud browser providers: Browserbase, Browserless, Browser Use, Kernel and AgentCore
• Built-in MCP server (`agent-browser mcp`) and version-matched agent skills (`agent-browser skills get core`)
• Experimental saved flows (v0.42.0): record a browser task once and replay its requests
• Native binaries for macOS, Linux (glibc and musl) and Windows

// Getting started

agent-browser ships as an npm package and a Homebrew formula with native binaries for macOS (ARM64, x64), Linux (ARM64, x64) and Windows (x64). The npm package needs Node 22 or later.

npm install -g agent-browser
agent-browser install

agent-browser open example.com
agent-browser snapshot -i       # interactive elements, each with a ref
agent-browser click @e1         # act on a ref from that snapshot
agent-browser get url           # check the result
agent-browser close

agent-browser skills get core
agent-browser skills list

agent-browser mcp

Commands and code are distilled from the project's own documentation — always check the official repo for the latest.

// When to use it

• Letting a coding agent check its own web UI changes in a real browser
• Filling forms and walking through multi-step web flows from an agent's shell
• Running isolated browser sessions in parallel, one per `--session`
• Pointing an agent at a hosted cloud browser instead of a local Chrome

// How agent-browser compares

agent-browser alongside other open-source computer & browser use tools AI/TLDR tracks, ranked by GitHub stars.