Response Headers

ai& exposes request metadata through HTTP headers rather than modifying the OpenAI- or Anthropic-shaped response body. This preserves wire-format compatibility with the official SDKs.

Identity & tracing

Header	Description
X-Request-ID	Unique ID for this request. Include in support tickets.
X-AiAnd-Org-ID	Organization the request was billed to.
X-AiAnd-Model	Model that actually served the request (after any aliasing).

Billing

Header	Description
X-AiAnd-Cost-USD	Cost of this request in USD. Set on every billable response.
X-AiAnd-Input-Tokens	Input tokens counted toward billing.
X-AiAnd-Output-Tokens	Output tokens counted toward billing.

Rate limiting

See Rate Limits for the full set of X-RateLimit-* headers.

Streaming

Streaming responses carry the identity headers immediately but emit cost/tokens via a trailer event after the model’s terminal message. See Streaming Events.

Note

Non-streaming responses always have cost and token headers. For streaming, read the trailer event — don’t try to parse them from headers, which are sent before the body completes.