Overlap

Git is built for merging into a mainline, not for knowing what other branches are touching right now. So conflicts get found late, at the pull request, once both sides have diverged enough to make the merge painful. Running several agents in parallel makes it worse: more branches, more commits, more chances two of them are quietly rewriting the same file.

Overlap watches the active branches on a repo and compares which files each one is changing. When two branches start overlapping, it says so, early, while the divergence is still small.

It’s a monorepo: a web app, an API, and a worker that does the polling and comparison, over Postgres with Drizzle. It ran on Railway for a while and isn’t deployed at the moment.