Kimi K2 Thinking is Moonshot AI's most capable open-source thinking model, extending the K2 series into agentic, long-horizon reasoning. Built on a trillion-parameter Mixture-of-Experts architecture that activates 32 billion parameters per forward pass, it interleaves step-by-step reasoning with dynamic tool invocation to maintain stable behavior across hundreds of sequential calls. Its 256k-token context window enables persistent workflows for autonomous research, complex coding, and multi-step analytical tasks that require sustained logical coherence without drift.

The model combines a large-scale MoE foundation with MuonClip optimization to balance deep reasoning capabilities against inference efficiency. It sets new open-source benchmarks on HLE, BrowseComp, SWE-Multilingual, and LiveCodeBench—performance that rivals leading proprietary models. Native INT4 quantization delivers lossless reductions in latency and GPU memory usage, making demanding agentic deployments more practical. Available as an open-weights release for commercial and non-commercial use, Kimi K2 Thinking represents a significant step in making advanced reasoning accessible beyond proprietary APIs.