# Prompt, token, context window

A prompt is your input. A token is a chunk of text (~¾ of a word) — models read and bill in tokens. The context window is the model’s working memory: how much it can consider at once, now often 200K+ tokens (a whole book).

Canonical: https://robauto.ai/learn/ai-101/4

_AI 101: The 2026 Foundation — lesson 4 of 20 (DEFINITION)_

A prompt is your input. A token is a chunk of text (~¾ of a word) — models read and bill in tokens. The context window is the model’s working memory: how much it can consider at once, now often 200K+ tokens (a whole book).

Source: [Anthropic Docs — Glossary](https://docs.claude.com/en/docs/about-claude/glossary?utm_source=robauto)

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