Context Window
The maximum amount of text an AI can read and remember in one conversation.
The context window is the total amount of text — your messages plus the AI's replies — that a model can hold in its working memory at once. Once you exceed this limit, the model starts forgetting the earliest parts of the conversation.
Think of it like a whiteboard. You can only write so much before you run out of space. When it fills up, you have to erase something from the top to write something new at the bottom. The AI can only see what's currently on the whiteboard.
A bigger context window doesn't mean the AI pays equal attention to everything in it. Research shows models often pay more attention to content at the beginning and end of a long context, and can "forget" details buried in the middle.