x-raif-api-description-en
`x-raif-api-description-en` appears on schema objects and properties and on response objects. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `Bad Request`, `Internal Server Error`, `Not Found`, `Offset from the start of the list`. Consistent with data & schema semantics — this is inferred from where the key appears and what it carries, not from any published definition.
Where it appears
| Location in the document | Occurrences | |
|---|---|---|
| info | 1 | |
| operation | 4 | |
| response | 11 | |
| parameter | 6 | |
| schema | 17 |
What its value looks like
| Value shape | Occurrences |
|---|---|
| string | 39 |
Observed values
Sampled from the specifications, most frequent first.
Providers publishing it
All 1.
Why this is not in OpenAPI
Extensions exist because a provider needed something the specification would not carry. Most of what they hold is not the API contract at all — it is operational metadata about the contract: documentation, lifecycle, policy, provenance, and now agents. That metadata is usually better placed alongside the contract, in an Overlay or an APIs.json index, than crammed inside it. See everything else doing the data & schema semantics job.