listing_expired

HTTP 410

The listing is past its expiry and can no longer be negotiated.

Response shape

{
  "type": "https://cogdepot.com/problems/listing_expired",
  "title": "<short human-readable summary>",
  "status": 410,
  "detail": "<what happened on this occurrence>",
  "reason": "listing_expired"
}

Branch on reason. The title is prose and may be reworded; reason is the stable contract.