What they did
The poster started by asking Claude (Opus, in the Claude app) to help clean up a Galaxy Watch4 Classic over ADB, which removed 21 apps they never used. They then decided to make their own watch face, something they had never done. They worked in small steps: describe the next feature, send a photo of the watch screen, and let Claude produce the next version. Claude drew all the artwork with Python, wrote the face in Google's Watch Face Format and packaged it as an APK that installs with adb. The result is a 45-second day and night loop with a farm scene, plus real data: time, date, a step arc toward the daily goal and the Samsung Health sleep score, with tap reactions and changes tied to battery level.
How it went
The face runs on the poster's watch, and the demo video is rendered from the same files. It did not load at first; Claude read the watch's error logs and fixed the problem. The poster published the APK and the full source on GitHub for free and called it one of the most fun things they have done with Claude. They give no time spent or cost.
Worth knowing
It has only been tested on a Watch4 Classic, so other Wear OS watches may not work. Installing it means sideloading with adb, which needs developer mode on the watch. The post does not say whether Claude ran the adb commands itself or the poster ran them from Claude's instructions.