#How it compares

The other browser tools for coding agents launch a browser of their own by default. reins uses the one you already have open, so you are already logged in everywhere.

##agent-browser

agent-browser (Vercel Labs) is a fast automation CLI that launches its own Chrome for Testing. It can reuse a profile's logins or attach to a running Chrome if you set that up. It adds HAR recording, request mocking and web vitals.

Pick it for headless runs, CI and request mocking. Pick reins to act as you, in your browser.

##dev3000

dev3000 (Vercel Labs) wraps your dev server, launches a monitored browser, and merges server logs, console, network and screenshots into one timeline for an AI to debug from.

Different job, and they combine well: dev3000 watches the app you are building, reins drives everything else in your browser.

##playwright-mcp

playwright-mcp (Microsoft) is an MCP server that launches a Playwright browser with its own profile. It has an opt-in extension mode that drives your real Chrome or Edge tabs, the closest thing to reins. You register it in each agent.

Pick it for Firefox and WebKit, device emulation, or clean isolated sessions. Pick reins for a plain CLI any agent can use with no setup, across all your Chromium browsers at once.

##What reins adds

An extension inside your browser instead of a debug port, per-site permission tiers, a redacted audit trail, and raw CDP when the built-in commands are not enough.