TestingCatalog reported that Moonshot AI launched Kimi K3.1 Pro, a 2.8T-parameter mixture-of-experts model with 104B active parameters and a 1M-token context window. It is available through Kimi’s web, mobile and API services, with open weights scheduled for November 4. TestingCatalog also reported that the model ranked fourth on the Artificial Analysis Intelligence Index, with a score of 55, and eighth on Arena’s WebDev leaderboard. These rankings were cited by TestingCatalog rather than confirmed directly from the original leaderboards.