Originally published at blog.whynext.app.
Work with AI agents for a while and the ambition comes naturally. While one session fixes a bug, another can refactor, and a third can investigate an issue, right? You can spin up as many models as you like, so productivity should scale to match.
That's how I started too. And within a week I learned that the real enemy of parallel agents isn't the models' skill. It's the working directory they share.
HEAD is a global variable
The cause fits in one sentence. When multiple sessions share a single git checkout, the current branch becomes everyone's global variable.
