Context window

Everything the model uses to answer has to fit in this window: instructions, conversation history, attached documents, tool results and the answer it is writing. What doesn’t fit, it doesn’t see.

In practice

• Very long conversations lose their beginning or start getting summarized.
• A large window doesn’t mean equal attention to everything. Information buried in the middle of a huge text tends to be used less.
• Agents manage the window for you, deciding what goes in at each step. That is the harness at work.
• Skills exist partly to save window space: they only load when the task calls for them.