If you're adding Now Playing metadata to an iOS app and want it to show up in CarPlay, this is mostly a reminder that you don't need to do anything extra. CarPlay reads directly from MPNowPlayingInfoCenter and MPRemoteCommandCenter, so if your lock screen integration works, CarPlay gets it for free. The skill covers optional CPNowPlayingTemplate customization for iOS 14+ if you want finer control over buttons and layout, but the core insight is that there's no CarPlay-specific code required. Budget 15-20 minutes if your Now Playing setup is already working. Part of the larger axiom collection from charleswiltgen, which has picked up nearly 1,000 GitHub stars.
npx skills add https://github.com/charleswiltgen/axiom --skill axiom-now-playing-carplay