Glossary — Language models
Context window
The context window is the amount of tokens a model can hold in mind at once — anything outside it does not exist as far as the model is concerned.
2 tokensContextwindow
Simply put#
A model does not have memory in the sense that you do. It has a window. Your question, its answer, the whole conversation so far and any attached files all have to fit inside it.
When a conversation runs long, the beginning slides out of the window. That is why AI "forgets" what you told it ten messages ago.
Example#
A 128,000-token window is roughly 300 pages of English text. In Estonian about a third less fits.
Why it matters to you#
In a long conversation it is worth restating the important things. And a large uploaded document consumes much of the window, leaving less room for everything else.