← Concept Index

Model foundations

Context windows

Also called: context length, working memory

DEFINITION

The context window is the maximum amount of text (measured in tokens) a model can consider at once — your prompt, the conversation so far, and any documents you paste, all together.

WHY IT MATTERS

Everything outside the window is invisible to the model. Long chats, big documents, and 'remember what I said earlier' all run into this hard limit, which is why answers can quietly drop earlier detail.

COMMONLY CONFUSED WITH

Long-term memory or training. The window is temporary working space for one session; nothing in it is learned or retained after the session ends.