# Moonshot AI Releases Kimi-K2 Reasoning Model

> The new Mixture-of-Experts model is designed for complex tasks but arrives in a custom compressed format with a restrictive license.

Published by The Open Weights on Nov 4, 2025. Canonical: https://theopenweights.com/news/kimi-k2-thinking-nc9g

## Key facts

- Company: Moonshot AI
- Model: Kimi K2 Thinking
- Version: K2 Thinking
- Category: Reasoning
- Modalities: Text / LLM, Reasoning
- License: Other (Open weights, commercial use allowed)
- Active parameters: 32B
- Context window: 262K tokens
- Architecture: DeepseekV3ForCausalLM
- Significance: major
- Published: 2025-11-04
- Last verified: 2026-06-17
- Hugging Face: https://huggingface.co/moonshotai/Kimi-K2-Thinking
- Canonical URL: https://theopenweights.com/news/kimi-k2-thinking-nc9g

Chinese AI startup Moonshot AI has released Kimi-K2-Thinking, a new open-weight model aimed at tackling complex reasoning problems. The company describes the model as being designed for tasks that require “extended thinking,” positioning it as a specialized tool rather than a general-purpose chatbot. Architecturally, it is a Mixture-of-Experts (MoE) model, a design known for efficient scaling.

Uniquely, the model is not distributed in a standard format like SafeTensors. Instead, Moonshot has released the weights in a proprietary compressed format with a ‘.sbs’ extension. To use the model, developers must rely on the company's corresponding open-source inference framework, Kimi-Inference, which is designed to handle this specific format. The full model is [available for download on Hugging Face](https://huggingface.co/moonshotai/Kimi-K2-Thinking).

## Licensing and Limitations

The release is governed by the custom "Kimi-K2-Thinking License." While it permits academic research and general commercial use, it includes a significant restriction: the model cannot be used for any commercial purpose that directly competes with Moonshot AI's own products or services. This kind of non-compete clause places it in a category of controlled-use models, distinct from permissively licensed open-source software.

This release highlights a growing trend of companies making powerful models publicly available under specific, often restrictive, terms. For researchers, Kimi-K2-Thinking offers a new architecture to explore for advanced reasoning. However, the non-standard weight format and licensing terms present hurdles for broad commercial adoption and straightforward integration into the existing open-source ecosystem.

## Get the model

- [Hugging Face](https://huggingface.co/moonshotai/Kimi-K2-Thinking)

## Sources

- [moonshotai/Kimi-K2-Thinking](https://huggingface.co/moonshotai/Kimi-K2-Thinking) — Hugging Face, Nov 4, 2025

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Source: The Open Weights (https://theopenweights.com/). Aggregated and written by Claude, curated by humans. Cite as: "Moonshot AI Releases Kimi-K2 Reasoning Model", The Open Weights, Nov 4, 2025, https://theopenweights.com/news/kimi-k2-thinking-nc9g