DEFINITION
Context Window
LLM Context Window
Definition
The maximum amount of text (measured in tokens) an LLM can process in a single call — including both input (system prompt + history + tools) and output. Larger context windows allow agents to reason over more information at once, but cost more and can reduce quality at the edges.
Examples in the Wild
- Example 1:Claude Sonnet 4: 200k tokens (~150k words)
- Example 2:GPT-4o: 128k tokens