Kimi K2 Thinking

• 🧩 Trillion-parameter MoE; 32B active per forward pass
• 📏 256k-token context window
• 🧠 Agentic long-horizon reasoning and chain-of-thought
• 🔧 Function calling and web search built in
• ⚡ INT4 quantization for efficient inference
• 🏢 Moonshot AI's most advanced open reasoning model

Moonshot

Moonshot is an AI research lab known for developing the Kimi family of large language models. The organization has gained recognition for building capable reasoning-oriented models, with the Kimi line representing its flagship series of text generation…

Kimi K2 Thinking is Moonshot AI's reasoning-specialized extension of the K2 architecture, released in December 2025 as the company's most capable open model for complex, multi-step problem solving. It uses a trillion-parameter Mixture-of-Experts design that activates 32 billion parameters per forward pass, balancing heavyweight intelligence with practical inference efficiency — further aided by INT4 quantization. The 256k-token context window makes it well suited for tasks that require ingesting and reasoning over long documents, codebases, or multi-turn agent workflows.

Within Moonshot's lineup, K2 Thinking sits as the deep-reasoning variant alongside the later Kimi K2.5, which continues the family's evolution. Its capabilities span code-optimized generation, function calling, and integrated web search, positioning it as more than a pure chat model — it is designed to act as an autonomous agent that plans, retrieves information, and executes tool calls across extended horizons.

This model is best suited for developers and power users who need strong chain-of-thought reasoning, long-context analysis, or agentic tool-use pipelines where accuracy on complex tasks matters more than raw speed.