Chinese AI startup Moonshot has unveiled Kimi K3, which it claims to be the world's largest open-weight AI model with 2.8 trillion parameters. Moonshot also claimed that K3 delivers performance that approaches Anthropic's Fable, considered to be the world's most powerful AI model, and Claude Opus 4.8, GPT-5.6 Sol and GPT-5.5 models. K3 can do advanced reasoning and long-horizon coding.