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

# Response Metadata

> Fields in the routing_metadata object returned with every API response

Every successful response includes a `routing_metadata` object with details about how the request was routed and its cost.

| Field                        | Type                 | Required | Description                                                                                                                                                                                                                                              |
| ---------------------------- | -------------------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `cost`                       | CostInfo             | No       | Cost for the request                                                                                                                                                                                                                                     |
| `cost.cache_savings_percent` | integer              | No       | Cache savings as integer percentage (0-100). Present only when savings > 0.                                                                                                                                                                              |
| `cost.cache_savings_usd`     | number               | No       | Cache savings in USD. Present only when savings > 0.                                                                                                                                                                                                     |
| `cost.usd`                   | number               | Yes      | Billable cost in USD                                                                                                                                                                                                                                     |
| `model_canonical`            | string               | Yes      | Canonical model ID requested                                                                                                                                                                                                                             |
| `provider`                   | string               | Yes      | Provider name (e.g., "fireworks\_ai", "anthropic")                                                                                                                                                                                                       |
| `provider_model_id`          | string               | Yes      | Provider's model ID                                                                                                                                                                                                                                      |
| `routing_strategy`           | string               | Yes      | Strategy used for routing. Known values: `cost`, `cost-focus`, `ttft`, `ttft-focus`, `tps`, `tps-focus`, `balanced`, `custom`. `custom` is returned when explicit `routing.weights` are provided. Additional strategies may be added in future versions. |
| `throughput_tps`             | number               | No       | Output throughput (tokens per second)                                                                                                                                                                                                                    |
| `ttft_ms`                    | number               | No       | Time to first token (streaming only)                                                                                                                                                                                                                     |
| `warnings`                   | StructuredWarning\[] | No       | Structured warnings emitted when the gateway modifies or ignores part of the request (e.g., unsupported parameters, blocked fields).                                                                                                                     |