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

# Response Schema

With each request, Prisma AIRS AI Gateway sends back **gateway-specific** headers that can help you identify the state of specific AI Gateway features you are using.

We send the following 4 response headers:

| Header                             | Value                                                                                                                                                                                                                                                                                                                                                                 |
| :--------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `x-portkey-trace-id`               | Returns a `unique trace id` for each response. In case the user has already sent a trace id with x-portkey-trace-id in their `request body,` then that is used here instead of generating a new id.                                                                                                                                                                   |
| `x-portkey-retry-attempt-count`    | Returns the number of `retry attempts` made for the call. Request made for the first time is not counted, `only` the attempts are counted. So, if the value is 3, that means that a total of 4 (1+3) calls were made.                                                                                                                                                 |
| `x-portkey-cache-status`           | Returns the `cache status` for the call. • HIT (simple cache hit) • SEMANTIC HIT (semantic cache hit) • MISS (simple cache header was sent in the request, but returned a miss) • SEMANTIC MISS (semantic cache header was sent in the request, but returned a miss) • DISABLED (no cache header sent) • REFRESH (cache force refresh was true in the request header) |
| `x-portkey-last-used-option-index` | Returns the nested `target index` (as jsonpath) for the Config id used while making the call.                                                                                                                                                                                                                                                                         |


## Related topics

- [Prisma AIRS AI Gateway Models](/docs/aigw/product/model-catalog/gateway-models.md)
- [Bring Your Own Guardrails](/docs/aigw/integrations/guardrails/bring-your-own-guardrails.md)
- [Open Responses](/docs/aigw/product/ai-gateway/responses-api.md)
- [Predibase](/docs/aigw/integrations/llms/predibase.md)
- [Messages](/docs/aigw/product/ai-gateway/messages-api.md)