5 people are already in — you can’t go below 6.
Edit plan. The create-plan sheet doubling as the host’s edit flow — opens prefilled from the hosted plan (“Rooftop sundowners on Friday”), header reads Edit plan and the CTA Save changes. No ✨ copilot card and no when-preset chips (both are create-mode accelerators); group size shows the floor note — “5 people are already in — you can’t go below 6.” — so a host can’t shrink below who’s confirmed.