Context is the lifeline of LLM. Without context (or with invalid context) an LLM is nothing but a gibberish word generating machine. Context allows for the LLM to personalize, reason, provide coherence and grounding for any response it generates. The Context Window is the model’s active memory. Claude Opus-4 for instance has a 200K token context window. It is huge and suffices for most of the tasks. But efficient use of the context window is also needed to improve coherence and dept in responses.