Mocking & testing

x-testDescription

`x-testDescription` appears on operations. Its value is a string. Used by 2 providers across 2 OpenAPI documents. Observed values include `Only the fields included in the request are updated in\`, `This resource does not have any attributes. Instead it\`, `Retrieves a list of entities that match different criteria\`, `The payload is an object representing the entity to be\`. Consistent with mocking & testing — this is inferred from where the key appears and what it carries, not from any published definition.

Mocking & testing 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.
67 occurrences
2 documents
2 providers
purpose-named

Where it appears

Location in the documentOccurrences
operation 67

What its value looks like

Value shapeOccurrences
string67

Observed values

Sampled from the specifications, most frequent first.

Only the fields included in the request are updated in\This resource does not have any attributes. Instead it\Retrieves a list of entities that match different criteria\The payload is an object representing the entity to be\Returns a JSON object with the attribute data of the attribute.\The request payload is an object representing the new\Removes an entity attribute.\nResponse:\n* Successful\This operation returns the `value` property with the value\

Providers publishing it

All 2.

fiwareribbon-health

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 mocking & testing job.

Work with this as data

Every extension here is available over the APIs.io API and to AI agents over MCP. OpenAPI Extensions is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for openapi extensions

3 MCP tools reach this
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools

Call it yourself

curl for this page
Search the catalog 
curl "https://apis.io/api/v1/search?q=x-testdescription&limit=10"
Everything under a tag 
curl "https://apis.io/api/v1/tags/x-testdescription"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no email required.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.