Ask anybody who locks up at night what has to happen before they leave and they will reel it off without thinking: gas at the wall, freezer read, fridges shut properly, back door, bins, sweep, alarm. Ask them whether the freezer actually got read last Friday and the answer is a shrug. The list lives in everyone's head, which is exactly why the same one or two things quietly stop happening and nobody notices for a month.
Shift Edges is a record of those two ends of the day, and deliberately nothing else. It knows nothing about your orders, your customers or your trade in between. It holds the fixed jobs at opening and the fixed jobs at closing, who ticked them, and what was left.
The list is drawn as a roller shutter. Every job due this morning is a slat, so the screen starts covered, and each one you tick rolls away into the stack at the top - the shutter climbs as the routine is worked, and the shopfront opens behind it. At night the same screen runs backwards: the slats start rolled away and each tick brings one down, closing the surface over until the place is shut. Half a routine looks like a half-open shutter, so a morning that was only partly done can never be mistaken for a finished one from across the counter.
Anything deliberately not done is punched through instead. The slat stays at full height with the ground showing where the metal should be, and that hole is the same shape everywhere else in the app, so a gap always means a gap. There is no button that ticks the whole list at once, and that is on purpose - knowing which single job was skipped is the entire reason to keep the record, and one tap for the lot would throw it away.
What the app does with those ticks is the part a notebook never manages. It reads every job across every day it has come round and separates a habit from a bad morning. A job missed on four Fridays out of five, and almost never otherwise, is drawn as a slat with a hole punched through the Friday position and named in plain words at the top of the screen. The same slices can be read by person instead of by day, so a job that only goes missing on one person's shift shows up as that rather than as bad luck. Crucially it refuses to say more than it knows: until a Friday has come round enough times, it tells you there are not enough Fridays yet, and where misses are spread evenly it says there is no pattern to it. Both of those thresholds are yours to set.
The rest of it is the awkward business of what a day actually is. A shop that shuts at half past midnight did not start a new day at midnight, so every routine is stamped against a working day that rolls over at an hour you choose. Start the closing routine while the morning list is still half ticked and the app closes the morning one out, recording what was left as not done rather than leaving it open for ever. Fill in a routine the next day from memory and the record says it was entered after the day, because it was. Mark a Sunday as closed and it produces no jobs and no misses at all, so the weekly day off never reads as a page of failure.
Shift Edges records what a member of staff ticked. It is not a safety, hygiene, security or compliance record, it certifies nothing, and it names no regulation, scheme or inspecting body a freezer reading on your list is a thing somebody checked, not a figure anybody else can rely on. It holds no money of any kind: no cash-up, no float, no till reading, no takings, no wages. It asks for first names only and nothing else about anybody, everything it keeps stays on the phone, and it makes no network request at all, so it behaves the same in a cellar with no signal as it does on the counter.
Opening and closing, kept: drawn as a shutter, so what's missed never hides.