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What is Context window?

Updated July 21, 2026 · by Pedro

The context window is the maximum tokens a model can see at once — system prompt, history, and the new message. Retry loops fill the window and raise cost without improving clarity.

Why does this term matter for AI prompts?

Precise vocabulary reduces vague instructions. When you name context window correctly in a brief, Claude, Cursor, and GPT spend fewer tokens guessing. Pair definitions with structure on AI prompt builder and cost math on prompt token cost.

More glossary terms

Full list: prompt engineering glossary.

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