[previously in series: 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ] Every city parties for its own reasons. New Yorkers party to flaunt their wealth. Angelenos party to flaunt their beauty. Washingtonians party to network. Here in SF, they party because Claude 4.5 Opus has saturated VendingBench , and the newest AI agency benchmark is PartyBench, where an AI is asked to throw a house party and graded on its…