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## Context window and longer responses for Pegasus 1.5

Pegasus 1.5 now uses a context window of 261,120 tokens that covers the combined input and output of each request. The maximum response length increases to 98,304 tokens (up from 65,536). These changes apply to [Sync analysis](/v1.3/api-reference/analyze-videos/sync-analysis) and [Create an async analysis task](/v1.3/api-reference/analyze-videos/create-async-analysis-task).

For details about what counts toward the context window, see the [Context window](/v1.3/docs/concepts/models/pegasus/pegasus-1-5#context-window) section.
Pegasus 1.2 still enforces the prompt limit of 2,000 tokens and supports responses up to 4,096 tokens.

### Truncated responses

When a response reaches the maximum response length or the context window, the platform returns the partial output and sets `finish_reason` to `"length"`. A warning appears in the `error` field. Asynchronous tasks with truncated output keep `status` set to `"ready"` and return both `result` and `error`.

Pegasus 1.2 async analysis tasks now also return `finish_reason` set to `"length"` when the response reaches the maximum response length. Previously, async analysis tasks always returned `"stop"`.

### Token usage

Responses for Pegasus 1.5 now include the `usage.input_tokens` field. Use it with `usage.output_tokens` to track how much of the context window a request uses.

For parameter details, see [Sync analysis](/v1.3/api-reference/analyze-videos/sync-analysis) and [Create an async analysis task](/v1.3/api-reference/analyze-videos/create-async-analysis-task) in the **API Reference** section. For truncation messages, see the [Error codes](/v1.3/api-reference/error-codes#the-analyze-endpoint) page.