What is Opal?
Opal is a screen-time and app blocker focused primarily on iPhone (with a Mac app too). It blocks distracting apps during sessions and gives you focus scores and streaks.
How they differ
Opal is aimed at phone distraction, and it's well designed for it. If your problem is reaching for your iPhone and falling into a feed, its blocking, sessions, and scores target exactly that.
AccountyCat is aimed at the other screen — the Mac you do deep work on. Instead of blocking apps on a schedule, it goes by your live work context (with AI that runs on-device or via your own cloud key) and nudges you when you've drifted from the task at hand.
For many people they're complementary: Opal to tame the phone, AccountyCat to keep desktop work on track. If your main issue is Mac focus, a context-aware nudge fits better than a phone-first blocker.