Models New
Moonshot AI releases Kimi K3.1 Pro, promises its open weights by 4 November, and an outside index ranks it fourth
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Moonshot AI released Kimi K3.1 Pro on 23 October, the first model in its K3.1 series, with a Highspeed variant it says runs two to three times faster. Both are available in Kimi.ai and the Kimi apps, Kimi Work, Kimi Code and the Kimi API. Moonshot says the full model weights will be released by 4 November.
K3.1 Pro is Kimi K3 with substantially more post-training compute and a 1-million-token context window. Moonshot calls it its most capable '3T-class' open-weight model; The Decoder reports the size is unchanged from K3, at 2.8 trillion total parameters with 104 billion active.
Moonshot reports 65.7 percent on the Terminal-Bench 4.0 coding-agent test, ahead of GPT-6 Astra at 58.2 percent and just behind Claude Opus 5.5 at 66.4 percent. The Decoder reports that Artificial Analysis gives the model 55 points on its Intelligence Index, 11 more than K3, placing it fourth behind Claude Opus 5.5 (58), Claude Sonnet 5.5 (56) and Muse Wonder Full (56), and that API prices fall by 33 percent.
Moonshot says the model's vulnerability-research ability kept rising as post-training scaled, that it traced this to cyber-related content inside its general mid-training data, and that it identified and removed such data and applied targeted controls during training to reduce misuse risk.
Caveat. Terminal-Bench and the other benchmark figures are Moonshot's own runs. Only the Intelligence Index score comes from a third party, as relayed by The Decoder. The weights are promised, not yet released.
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