Kimi K3.1 Pro: Moonshot AI serves up its first Pro

Moonshot AI officially released Kimi K3.1 Pro, with a parameter count on the order of 3 trillion, support for a 1 million token context, and confirmed its identity as Kibitz, the previously anonymous model in Arena blind testing. The model launched the same day on Kimi web, App, Kimi Work, Kimi Code and the API, and full weights will be released by November 4. According to the official blog, the model underwent large-scale reinforcement learning post-training on the K3 base, scoring 55 on the Artificial Analysis Intelligence Index, an 11-point improvement over K3 and fourth place globally; Artificial Analysis said that after the weights are released it will become the highest-scoring open-weight model. Official benchmark tables show a Terminal-Bench 4.0 score of 65.7%, higher than GPT-6 Astra's 58.2% and 0.7 percentage points below Claude Opus 5.5's 66.4%; agent capabilities and front-end 3D creation are the focus of this upgrade.