A command center is the one full checkout of a repository, kept permanently on its base branch and always clean, that a set of isolated worktrees are created from and periodically synced back to — as distinct from any of the worktrees themselves, where actual work happens.
In a multi-agent or multi-branch Git workflow, the command center is never used to write commits — its only jobs are spawning new 📝worktrees from the latest base branch and pulling that base branch's updates so the next worktree starts current. Everything else — agent sessions, feature work, testing — happens in a worktree, a separate working directory attached to the same repository.
Keeping the command center strictly clean and on-branch is what makes spawning new worktrees safe to automate: a tool that creates a worktree can assume the base branch is trustworthy without checking history for stray commits first. A dirty or off-branch command center is a common and disruptive failure mode in practice — usually caused by a commit landing there directly instead of in a worktree, which then blocks every future worktree creation and pull until it's cleaned up.