Moonshot AI on November 4 released the model weights of its large language model Kimi K3.1 Pro for free, distributed on Hugging Face and downloadable and usable by anyone. The published repository consists of 96 weight shards with a total size of about 1.56 terabytes. Kimi K3.1 Pro began advance availability in late October through a web interface, mobile app and API, and the company has now followed through on its earlier pledge to release the weights. The model uses a mixture-of-experts (MoE) architecture with 2.8 trillion total parameters and 104 billion active parameters at inference, with a context window of up to 1 million tokens. It strengthens agentic functions such as coding, 3D production and financial research, and on some benchmarks posts results surpassing leading-edge models from major players such as GPT-6 Astra and Claude Fable 5.1. The license follows the proprietary terms used for the previous-generation K3, permitting free use, modification, redistribution and commercial use while setting two conditions: a separate agreement with Moonshot AI is required before commercial use for operators of a model inference or fine-tuning service whose combined revenue of the company and its affiliates over the past 12 months exceeds $20 million, and products using the model that exceed 100 million monthly active users or monthly revenue exceeding $20 million must prominently display "Kimi K3.1-Pro" on screen. Neither requirement applies to purely internal