A cron job can keep your local patches rebased against upstream automatically.

Willison highlighted a David Crawshaw prompt that turns fork maintenance into a scheduled agent task: rebase local modifications against upstream on a cadence, report what it had to resolve. This is the lowest-blast-radius entry point into scheduled agent loops I've seen, because the failure mode is a conflict report, not a broken main. Pair it with worktree isolation so the rebase attempt never touches your working copy.