Kimi K2 Base is a raw, uninstruction-tuned foundation model, meaning it completes text rather than following conversational instructions — it's the clay before the sculpture. With a 131K token context window, it can hold large volumes of text in working memory at once, making it suited for long-document processing tasks. As a base model, it requires fine-tuning or prompting expertise to get useful outputs; it won't behave like a chat assistant out of the box.