The context window, hands-on
What you see
A conversation as chips, and a fixed-size window showing only the most recent messages. The slider makes the chat longer.
What it shows
Why models seem to forget: whatever slides out of the window no longer exists for the model — and compacting saves the essentials, not everything.
- You: Hi! One thing up front.
- You: 4-7-1-9 is the door code — please remember.
- AI: Noted, 4-7-1-9.
- You: What's the weather tomorrow?
- AI: Changeable, around 14 degrees.
- You: And the day after?
- AI: A bit warmer, sunny spells.
- You: Thanks! What should I cook today?
- AI: How about roasted veg?
- You: Good idea. Shopping list?
- AI: Peppers, zucchini, potatoes, oil.
You (now): So what was the door code again?
The door code is still in the window — readable.
This toy window counts messages — real models count tokens, small pieces of words. How many fit differs between models by orders of magnitude. And however large: a bigger window pushes the overflow back — it doesn't abolish it.
That's exactly why it helps to put important things last, start a fresh session, or let the tool compact the history — see the article on context rot.