We have about 70 volunteers, four shifts a day and a lot of last-minute cancellations. I was spending most of Friday on scheduling. Now it takes about 40 minutes, and here's the whole setup.
The sheet: first names, availability, skills (driving, warehouse, front desk) and "never" notes.
Prompt 1, draft: paste the sheet, ask for next week as a table, NEVER rules listed first.
Prompt 2, check: in a fresh chat, paste the draft and the rules and ask "find every rule this schedule breaks." A second pass with fresh eyes catches far more than asking the first chat to check itself.
Prompt 3, messages: turn the final schedule into short, friendly reminder texts, one per volunteer, which I send myself.
The fresh-chat check is the trick. The first chat defends its own work; the second one doesn't care.