Arc Browser Use
Codex can drive your real browser through OpenAI's ChatGPT extension, but Arc isn't one of its browsers. The extension installs and connects in Arc, then the first tab Codex opens never finishes loading. I wrote arc-browser-use, which rebuilds the official extension on your Mac with that one step skipped.
Below are the details I spent the most time on.
The tab that never loads
Before the extension loads a tab, it puts the tab in a group and waits for chrome.tabs.group(). Arc has that API but never answers it. The first request hangs, and every request queued behind it waits too.
One early return, found by name
The fix makes ensureAgentTabGroup return before it groups anything. background.js is KB minified onto lines, and its short names change every release, so the patch finds the method by its name, which the minifier keeps.
Arc, by name
A second, optional patch makes the extension report its name as Arc, so Codex lists Arc instead of Chrome. If it ever stops matching, the build skips it with a warning and still works.
Checked before it's changed
The build downloads the extension from the Chrome Web Store and reads the CRX3 file itself: a -byte signed header in front of a MB archive. It verifies the publisher's signature with openssl before it unzips anything.
The store's ID, kept
The ChatGPT app's native connector only answers one extension ID. Chromium derives an ID from the SHA-256 of the publisher's public key, so the build copies that key into its manifest, and Arc gives the copy the official ID. Arc finds the connector in Chrome's own folder, so Chrome doesn't need to be installed.
A doctor that says what to do
doctor checks Arc, the connector, the ChatGPT app, the build, Developer mode and the newest store version, one line each. Every FAIL comes with its fix, including the one people miss: turn the extension off and on, because Reload doesn't reconnect.
Set up by a coding agent
SETUP.md is written for agents. Paste its link into Codex and it runs the commands, stops only for the one click Arc needs, then checks its own work by opening example.com in Arc.
A weekly job builds the newest store version every Monday and opens an issue if a patch stops applying. I tested 0.1.0 with ChatGPT extension , Arc and the ChatGPT desktop app .