Tooth Fairy
Radar

The repo remembers two eras

The original README still says: create a new Xcode project, then “replace the generated files with the files provided.” That’s code handed over as text, pasted in by hand — how I was working with AI when this started. Sitting right next to it: an agent instruction file and agent-co-authored pull requests from three months later.

The commit history tells the same story. First commit: an empty Xcode template. Four days later: the whole app arrives in one commit. On the App Store three weeks after that.

She's only ever over the night side of the planet

The radar isn’t a random shuffle. A thirty-line solar-time calculator — UTC plus longitude over fifteen — filters twenty world cities down to the ones where it’s currently between 18:00 and 06:00 solar time, and the fairy only patrols those. Open the app at noon in New York and she’s over Tokyo, for a real reason. The illusion is backed by arithmetic.

The QA plan has a section called Chaos / Kid Testing

The adversary is a seven-year-old. Tap “Tooth is Under Pillow” twenty times fast: exactly one flight launches. The storage layer assumes the worst, too — every write lands in a primary and a backup key, corrupt data gets quarantined instead of deleted, and records written by version 1.0 still decode after four schema changes.

My favorite rule is in the iCloud merge: most fields are last-write-wins, but “has the child seen the morning reveal” merges asymmetrically. Once seen, no device can un-see it. Nobody’s kid gets the magic spoiled by a sync conflict.

Then I sent the agent back in

Months after shipping, I had a coding agent audit my first app. It found seven real defects: a deployment target set to a version of iOS that doesn’t exist, an iCloud change-observer that had been commented out — silently disabling cross-device sync — a settings screen hardcoded to say “Authorized,” two toggles wired to nothing.

Then came the rework: a 60fps timer became a proper display link, and two near-identical sync stores collapsed into one generic implementation at roughly half the code. My first app got a second education, and so did I.