This is great, and serendipitous timing for me.

After spending an embarrassing amount of time on today's hard before I went to bed I was wondering what kind of metrics could go into analysing the difficulty of any Pips game (and which ones NYT Games uses) and whether it would be worth writing a solver to do this analysis. I was also considering an SMT or CP approach instead of backtracking as an alternative.

Edit: And after looking through the solve times in more detail, I feel vindicated that the hard for today (01/11/2025) was both a single solution and took the solver over 8x as long to find the solution. It took me longer than 8x my average, but that's besides the point...