Picked "next Monday," and it was a holiday

Scheduling and messages

Situation: Using a tool to pick the first day of next week for a weekly meeting. The record is from Japan, where several public holidays fall on Mondays.
What the AI did: It simply picked "next Monday," so in holiday weeks it landed on a day the office was closed and the meeting couldn't be booked. It hadn't checked for holidays.
How to ask next time (the site author's example): "When picking a date, remove holidays and days off first, then pick. Check that the chosen day can actually be used for this."
One question to ask: When would this date be unusable (holidays, days off)?
Check it yourself: Mondays break this outside Japan too: five US federal holidays always fall on a Monday, and four of the eight bank holidays in England and Wales usually do. Run the date logic over a full year and list what it picks.
AI used (month): Claude Code (2026-09)
Times this mistake was recorded: once
Source: The site author's notes from their own work (the original task was replaced with a different one)