Chinese AI start-up Moonshot has unveiled Kimi K3, a 2.8-trillion-parameter model it says can rival top American systems, at the World Artificial Intelligence Conference in Shanghai last week.
Moonshot describes K3 as its most capable flagship model yet, built for long-horizon coding, agentic knowledge work and reasoning, with native vision and a one-million-token context window. The company says it will be the world's first open model in the three-trillion-parameter class when full weights are released on 27 July, freely downloadable and customisable by outside developers.
Moonshot's own benchmarks place K3 behind proprietary rivals Claude Fable 5 and GPT-5.6 Sol overall, though it says the model performs at a frontier level across its evaluation suite. The BBC reports that third-party evaluations from Artificial Analysis and Arena.ai show K3 performing on a par with leading US models, and ranking first in web interface engineering ahead of Anthropic's Fable 5 in blind human-preference tests.
Backed by Alibaba and Tencent, Moonshot said K3 is designed to operate with minimal human supervision on complex engineering tasks.
