Drop a screenproof.json next to where you run screenproof (or pass --config <file>). Every key is optional and merges over the built-in defaults.
rules: rule id to level (error,warning,info,off). The example turns on the two opt-in rules (screenshot-primary-size-missing,screenshot-locale-parity) and promotes the alpha check to an error.locales.allow: when set, only these locale folder names are valid (allow-list).locales.extra: extra locale codes to accept in addition to the built-in App Store list.locales.ignore: folders to skip entirely (the example skips anarchive/folder).dimensions: device-class overrides. A known class id (see the README table) replaces that class's size lists; an unknown id adds a new custom class. Sizes are[width, height]pairs. Use this to add a new Apple size the day it ships, without waiting for a screenproof release.