Ostinato

A day is not a block. It is a partition.

Focus timers repeat one block all day. Ostinato writes the whole day — warm-up, deep blocks, recovery, surface work, descent — around the meetings you already have.

What was measured

Seven focus timers were compared. Five adapt to nothing; two adapt only if you configure them by hand. And what they measure is sessions, streaks and trees — none of which is evidence that the day worked.

Ostinato's rules are checked by a second implementation that shares no constants with the one that writes the day. Across 36,000 days no partition broke a rule; a fixed cycle that knows your work type, the block ranges and your calendar — everything except the shape of a day — broke one in almost all of them.

	Ostinato	fixed cycle
capacity left at end of day	0.769	0.678
deep minutes in the first half of a long day	62.5%	54.5%

A fixed cycle spends your capacity. Ostinato protects it, because it puts recovery where recovery belongs rather than every 25 minutes regardless.

Your curve

After each block, one tap: went well · was weak · didn't happen. That is the only thing Ostinato measures. It builds your own decline curve on the device, and after about ten blocks the day is written from you rather than from a stated average.

What it will not do

• No streaks, trees, badges or leaderboards. Abandoning a bad day is sometimes the right call.
• No blocking of sites or apps.
• No account, no server, no sync, no network.
• No reading of your calendar's contents. Only the times you are busy — titles, guests, notes and locations are never touched, and a build gate enforces it.
• No subscription.

Apple Watch

The current block, how long is left, and a tap on the wrist when it changes. Nothing to read. The watch regenerates the partition from a deterministic seed rather than downloading it, so it stays right if the connection drops.