Context Window
The amount of text an AI model can remember and process at once, measured in tokens. Bigger windows mean longer conversations and documents.
What is Context Window?
A context window is the working memory of an AI model - how much text it can keep track of while generating a response.
It's measured in tokens (roughly 3/4 of a word each). Claude 3.5 Sonnet has a 200K token window (about 150,000 words). GPT-4 ranges from 8K to 128K depending on the version.
When you hit the limit, the model starts forgetting earlier parts of your conversation or cuts off mid-response. Builders use larger windows for analyzing full codebases, processing long documents, or maintaining context across complex multi-step tasks.
Longer contexts cost more because the model does exponentially more computation. A 100K token input costs roughly 100x more to process than a 1K token input.
Good to Know
Measured in tokens - roughly 3/4 of a word in English
Includes your prompt, conversation history, attached docs, and the model's response
Larger windows enable analyzing full documents, entire codebases, and longer conversations
Processing cost grows quadratically with window size - 10x longer input costs 100x more
Modern models range from 4K tokens (basic chat) to 1M+ tokens (full document analysis)
How Vibe Coders Use Context Window
Pasting your entire codebase into Claude and asking it to refactor a feature across multiple files
Analyzing a 50-page contract or research paper in one conversation without losing context
Building a chatbot that remembers the full conversation history instead of forgetting after 10 messages
Processing multiple customer support tickets at once to find patterns and suggest responses
Frequently Asked Questions
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