SparkChess AI opponents are engineered to behave like casual human players, not robot overlords. Except for Guru, they’ll play fast and loose and will favor variety over the best move. Cody is child-like an Deon is still learning the basics. So our advice would be to just play and have fun!
If you must know, Claire has an Elo rating of 1500 depending on her mood. Boris is 1700 on a good day and Guru is around 1900-2000. If you really need a stronger opponent, we could go as high as 2100.