Lesson 04

The context window

It has no memory. It re-reads the whole chat, every single time.

The model remembers nothing between messages. Every turn, the app quietly re-sends the entire conversation and the model reads all of it from scratch. That re-sent text has a size limit, and the limit is called the context window.

It remembers everything inside the window and nothing outside it. The elephant is the flattering half of that; the edge of the window is the rest.

Do thisPress Next message ten times. Watch the window in step 3 fill up, then watch the first message get pushed out of it. At the end, Sam asks the model his own name.

1Send the chat, one message at a time

0 of 10 sent

2The chat, the way you see it

3What the model actually gets, this turn

Step 2 is the chat the way you see it. Step 3 is the text the app actually sends, re-sent in full every turn. This demo uses a deliberately tiny 60-token window so you can watch it overflow; a real one holds tens of thousands.