tl;dr - typing /login in claude code in a docker container will do auth in your host's browser :)

My team and I develop almost exclusively in dev containers. If you initiate an oauth2 auth from inside the dev container (for claude, azure cli, etc) you either (a) have some annoying copy and pasting to do or (b) you are using VS Code which magically makes it work with your host browser.

This utility makes the VS Code magic into a standalone utility so you don't need to be using VS Code but still get automatic proxying of your oauth2 requests to your hosts browser.

The basic idea (which is what VS Code does under the hood I believe) is to set up a server<->client relationship between host<->container that grabs your container-based cli tools browser open request, forwards out to the host, does oauth, forwards it back into the container.

We've been using it for a while and it works great. Thought I'd share.