Data & schema semantics

x-probe

`x-probe` appears on operations. Its value is a structured object. Used by 5 providers across 6 OpenAPI documents. Consistent with data & schema semantics — this is inferred from where the key appears and what it carries, not from any published definition.

Data & schema semantics derived description

How this description was produced. It is assembled from what was measured in the corpus — where this key appears in a document, what shape its value takes, the values observed, and how many providers use it. It is not taken from a published definition, because for most extensions none exists. Read it as evidence, not as a specification. If you own this extension and want it described properly, tell us.

149 occurrences

6 documents

5 providers

purpose-named

Where it appears

Location in the document	Occurrences
root	2
operation	147

What its value looks like

Value shape	Occurrences
object	137
string	12

Observed values

Sampled from the specifications, most frequent first.

{date: '2026-09-01', status: 200, content_type: application/json}{date: '2026-09-01', status: 404, note: probed with a deliberately invalid id to{date: '2026-09-01', status: 200, content_type: image/jpeg}{date: '2026-09-01', status: 200, content_type: application/json, bytes: 1284290

Providers publishing it

All 5.

california-attorney-general election-assistance-commission hku university-of-lisbon university-of-los-andes-colombia

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.