Kimi K3 is an ultra-large-scale, open-weight multimodal reasoning model from Moonshot AI, built on a Mixture-of-Experts architecture with approximately 2.5 trillion total parameters and a 1-million-token context window. It is designed for complex coding, knowledge work, and long-horizon agentic workflows, excelling at multi-step autonomous execution and large-context reasoning tasks. Kimi K3 is the third-generation flagship in Moonshot AI's Kimi series, succeeding the Kimi K2 family, and targets frontier-level performance on coding and agent benchmarks.