Open shift
An open shift is a shift that exists on the schedule with nobody assigned to it, or with fewer people on it than it needs. It is work the workplace has already decided it wants covered and has not yet found somebody for.
Why it matters in a small workplace
An open shift on a slot the workplace cannot run without is the difference between opening and not opening. Finding it on Wednesday is a staffing question; finding it on Sunday morning is an emergency.
How Weeksort handles it
A mandatory slot that is still short is flagged while you build, and counted in the strip above the week. Staff see the open shifts they are eligible for and can ask to take one; a manager approves, and the schedule updates itself.