Documentation & DX

x-title

`x-title` appears on operations. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `Fields`, `Exclude Fields`, `List ID`, `Count`. Consistent with documentation & dx — this is inferred from where the key appears and what it carries, not from any published definition.

Documentation & DX 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.
825 occurrences
1 documents
1 providers
purpose-named

Where it appears

Location in the documentOccurrences
operation 824
schema 1

What its value looks like

Value shapeOccurrences
string825

Observed values

Sampled from the specifications, most frequent first.

FieldsExclude FieldsList IDCountOffsetStore IDCampaign IDSubscriber Hash

Providers publishing it

All 1.

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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 documentation & dx job.