I built a cookie bridge, then changed my entire agent setup

A developer built Browser Cookie Bridge, a macOS app that transfers cookies from Chromium browsers like Brave into AI coding agents' in-app browsers so agents can start from existing logged-in sessions. After hitting RAM limits with the Codex desktop app and session-sync gaps including passkeys, the developer moved to terminal agents in cmux and adopted Vercel Labs' agent-browser MCP with a Chrome profile-reuse rule in AGENTS.md, logging 616 agent-browser calls across 11 threads from October 8 to 11. Vercel CEO Guillermo Rauch replied to the shared setup, "This is the way. more to come!

I wanted my coding agents to use the websites I was already logged into. That small problem ended up changing my whole setup. I started with the Codex desktop app and its in-app browser. Importing my Chrome session was convenient: the agent could work with sites where I was already signed in. Then I switched to Brave, and the import option I needed was missing. My accounts were signed in over there while the agent was working somewhere else. So I built Browser Cookie Bridge, a macOS app that started by moving Brave cookies into Codex and grew to support more Chromium browsers. When I tried Grok Bot later, I used Cookie Bridge there too, exporting a cookie bundle into its browser. I kept wanting the same thing: let the agent start from the session I already have. The code: https://github.com/apoorvdarshan/browser-cookie-bridge https://github.com/apoorvdarshan/browser-cookie-bridge The RAM usage of the Codex desktop app eventually pushed me toward terminal interfaces. I started using cmux, which also had an in-app browser with session import built in. That helped, but I still had to sync often. Some Google sessions did not come across properly, and some passkey flows did not work as expected. I would start a task and end up spending time getting the browser signed in again. Cookie transfers helped, but they could not carry everything, including passkeys. Eventually I tried agent-browser from Vercel Labs and added this rule to my AGENTS.md: Use the agent-browser MCP for web browsing by default headless, logged out . If a site needs my login, relaunch it with --profile Default to reuse my Chrome logins. Most browsing starts without my accounts. When a task needs a login, the agent uses the Chrome profile flow. That flag launches a temporary copy of the profile, so session reuse becomes part of the workflow instead of another import I have to arrange by hand. I still handle a fresh login or passkey approval when needed. But now I can use Claude Code, Codex or OpenCode in cmux with the same browser rule. I shared the setup on October 9: // Detect dark theme var iframe = document.getElementById 'tweet-2108313693696188526-473' ; if document.body.className.includes 'dark-theme' { iframe.src = "https://platform.twitter.com/embed/Tweet.html?id=2108313693696188526&theme=dark" } Guillermo Rauch replied, "This is the way. more to come " A nice surprise after all that fiddling with browser sessions. // Detect dark theme var iframe = document.getElementById 'tweet-2108314389170516471-245' ; if document.body.className.includes 'dark-theme' { iframe.src = "https://platform.twitter.com/embed/Tweet.html?id=2108314389170516471&theme=dark" } I checked my saved agent threads before writing this. Across October 8 to 11, the audit found 616 recorded agent-browser calls and command batches in 11 threads. That includes retries and batches with multiple actions, so it is a usage count, not 616 completed tasks. Those threads covered the Omi website and leaderboard, a ringtone editor, my portfolio and resume, marketing, and research. I knew I was using it a lot. The history made that obvious. This was my follow-up: // Detect dark theme var iframe = document.getElementById 'tweet-2109099239699890312-532' ; if document.body.className.includes 'dark-theme' { iframe.src = "https://platform.twitter.com/embed/Tweet.html?id=2109099239699890312&theme=dark" } Browser Cookie Bridge still helps when I want sessions inside an in-app browser. For everyday work, I now prefer terminal agents with a browser tool they can call when needed. Thanks @vercel https://x.com/vercel , @v0 https://x.com/v0 and @rauchg https://x.com/rauchg for the work you're putting into tools for builders. agent-browser has saved me a lot of time. I get to spend more of it actually shipping. I wanted to build apps. I did not expect browser logins to shape so much of how I build them. Try it: https://agent-browser.dev https://agent-browser.dev . Chrome profile details: https://agent-browser.dev/sessions https://agent-browser.dev/sessions . Originally published on X https://x.com/apoorvdarshan/status/2109119525954216286 .