Hi Product Hunt, We're Lightning LLC, a small studio in Tokyo. Earlier this year we shipped KeyAlarm, which turns calendar events into real alarms. Since then we kept wanting the same thing for our to-dos. MustDo is that app. Why we built it: a to-do with a notification is a to-do you can swipe away. We kept doing exactly that: "take the medicine at 9", "call the bank back", "put the bins out". The banner came and went while the phone was face down. What we wanted was the morning-alarm kind of reminder: it rings until you reach over and deal with it. What's different: - It's a real alarm, not a notification. MustDo uses AlarmKit (iOS 26), the same system behind the Clock app. Full screen, audible through Silent mode and Focus, and it keeps ringing until you stop it. - Stopping it means done. The to-do moves to Completed. Tapped by mistake? Swipe to undo. - Not done yet? Snooze 10 min, 1 hour, or tomorrow, right on the alarm screen and in the Live Activity. It comes back as many times as it takes. - Type one line and it's tomorrow at 9:00 by default (you can change the time). Repeats work like the Calendar app: daily, weekdays, every other week, monthly, yearly. - Your to-dos stay in your iCloud (CloudKit private database), synced across your devices by Apple. No server of ours stores them. No account, no sign-in. The part we're most curious about: MustDo works with MCP. Tell Claude "add 'pick up the dry cleaning' to MustDo" and it lands in your iCloud and rings on your iPhone at the time. On a Mac it runs locally; from the Claude iPhone app or claude.ai there's a connector (https://ltng.jp/mustdo/mcp). The relay holds only your encrypted iCloud sign-in token, never the to-dos themselves. Pricing, honestly: it's free for 30 days, then a subscription (monthly or yearly; the App Store shows your local price). We went with a subscription rather than one-time because the MCP connector costs us money to run. Two things we promised ourselves: no account is ever required, and to-dos you've already added keep ringing even if you never subscribe. The only thing that stops is adding new ones. An alarm app should never go quiet over billing. 25 alarm sounds, optional Face ID lock, 8 languages, iOS 26 and up. What would you want to ring until it's done? And if you use Claude, we'd love to hear how you'd wire it in. Ask us anything.

MustDo

A to-do alarm that rings until done. Snooze until you do.

A to-do alarm that rings until done. Snooze until you do.