Data & schema semantics · Mutability & access

x-ms-mutability

`x-ms-mutability` appears on schema objects and properties. Its value is a list. Used by 6 providers across 177 OpenAPI documents. It sits in the `x-ms-` namespace, so its meaning is defined by ms tooling rather than by OpenAPI. Consistent with mutability & access — this is inferred from where the key appears and what it carries, not from any published definition.

Data & schema semantics x-ms- namespace 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.
1230 occurrences
177 documents
6 providers
vendor-named

Where it appears

Location in the documentOccurrences
schema 1186
tag 44

What its value looks like

Value shapeOccurrences
array1230

Providers publishing it

All 6.

azure-container-registryazure-function-appsazure-functionsazure-storage-accountazure-storage-accountsmicrosoft-azure

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.