x-omitempty
`x-omitempty` appears on schema objects and properties. Its value is a boolean flag. Used by 27 providers across 40 OpenAPI documents. Consistent with sdk & code generation — 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 | |
|---|---|---|
| schema | 2176 | |
| operation | 8 | |
| tag | 23 | |
| server | 1 | |
| header | 1 | |
| response | 31 | |
| parameter | 1 |
What its value looks like
| Value shape | Occurrences |
|---|---|
| boolean | 2237 |
| string | 4 |
Observed values
Sampled from the specifications, most frequent first.
Providers publishing it
All 27.
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 sdk & code generation job.