> ## Documentation Index
> Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# DecisionsResponseUsage

## Fields

| Field | Type | Required | Description | Example |
| - | - | - | - | - |
| `cost` | *Optional\[float]* | ➖ | What OpenRouter charges for the request, in credits. On a BYOK request this is the OpenRouter fee only. | |
| `cost_details` | [OptionalNullable\[components.CostDetails\]](../components/costdetails.mdx) | ➖ | Breakdown of upstream inference costs | \{ "upstream\_inference\_completions\_cost": 0.0004, "upstream\_inference\_cost": null, "upstream\_inference\_prompt\_cost": 0.0008 } |
| `input_tokens` | *int* | ✔️ | N/A | |
| `input_tokens_details` | [Optional\[components.DecisionsUsageInputTokensDetails\]](../components/decisionsusageinputtokensdetails.mdx) | ➖ | Of `input_tokens`, those the provider served from its prompt cache. | |
| `is_byok` | *Optional\[bool]* | ➖ | Whether a request was made using a Bring Your Own Key configuration | |
| `output_tokens` | *int* | ✔️ | N/A | |