from the basic pdf:

Divine Intervention
Beginning at 10th level, you can call on your deity to intervene on your behalf when your need is great.
Imploring your deity's aid requires you to use your action Describe the assistance you seek, and roll percentile dice. If you roll a number equal to or lower than your cleric level, your deity intervenes. The DM chooses the nature of the intervention; the effect of any cleric domain spell would be appropriate.
If your deity intervenes, you can't use this feature again for 7 days. Otherwise, you can use it again after you finish a long rest
At 20th level, your call for intervention succeeds automatically, no roll required.
that's probably the closest thing we have to something that's really "broken" (which is a term i hate, because people tend to throw it around too often and apply it to things that don't work exactly how they want them to), but even that has some stuff balancing it out, like the low percentage of failure (less than five percent even at level 19...though it jumps up to a sure thing at the next level) and the thing where you can only use it successfully once a week and if you fail, you can't just keep trying an unlimited number of times.