Moonshot AI releases Kimi K3.1 Pro, promises open weights by Nov. 4

Beijing-based Moonshot AI introduced Kimi K3.1 Pro, the first model in its K3.1 series, and promised a public release of the full model weights by Nov. 4, 2026, according to a report by Crowdfund Insider.1

The company built the model on the earlier Kimi K3 with substantially increased post-training computation, including large-scale reinforcement learning across hundreds of domains, according to Crowdfund Insider.1 The report cites the company's own claims and links to a Moonshot blog post; the full text of that post was not among the sources reviewed.1

According to Crowdfund Insider, the model keeps a mixture-of-experts architecture with about 2.8 trillion total parameters and roughly 104 billion active per token, and adds a one-million-token context window and support for text plus image inputs; some descriptions also mention video, which the report does not confirm.1

The company reports 65.7 percent on Terminal-Bench 4.0, ahead of OpenAI's GPT-6 Astra and narrowly behind Anthropic's Claude Opus 5.5 in the company's published comparisons.1

Independent evaluations place the model fourth overall on the Artificial Analysis Intelligence Index shortly after launch, according to the report, which did not name the evaluator beyond the index.1

The company applied data-filtering measures during training to restrain certain vulnerability-research capabilities ahead of the open-weight release, the report said; it did not describe what data was filtered.1