Everyone merges small changes into one main branch, at least daily, and nobody keeps a branch going for long. Unfinished work stays hidden behind flags.
The longer a branch lives, the more it and main both change, and conflicts grow faster than the time does. Parallel agents sharpen this, because each one is a branch.
Say it to your agent
“Rebase on main before you start, keep this branch under a day, and merge behind the new-search flag even though it isn't finished. If you can't split it that small, stop and tell me why before you write more.”