409 with a region_error body that identifies the expected or requested region. Responses expose X-Overshoot-Region with the serving region.
One chat-completions request cannot reference streams from multiple regions.
Region behavior
Send the X-Overshoot-Region header to route a request to a Stream’s owning region and skip the extra 409 redirect and retry step.
Streams are regional resources. If your application knows which region owns a stream, you can include a region header to avoid an extra redirect/retry step.
Clients may send:
or:
If a request reaches the wrong region, the API returns