Context window planner

See how much of your model's context window the system prompt, tool definitions, retrieved documents, chat history and reply reserve take up, and how much room is left.

Free, no sign-up. Runs entirely in your browser: nothing you type is sent to AgentScout or any AI provider.

Token counts for pasted text are estimates from the same method as the token counter. Price thresholds also matter: some providers bill long prompts at a higher rate (see the notes in the cost calculator).

FAQ

What is a context window?

The maximum number of tokens a model can take in one request, counting the system prompt, tool definitions, conversation history, documents and the reply it writes.

Why reserve tokens for the reply?

The model's output shares the same window on most APIs. If the input fills it, the reply gets cut short or the request fails.

Why doesn't AgentScout list each model's context size?

Sizes change often and can differ by plan, region or API tier, so we only show figures you can check. Enter the number from the provider's model page.

What if I'm over the limit?

Trim history (summarize older turns), retrieve fewer or shorter documents, shorten tool descriptions, or choose a model with a larger window.

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