x-speakeasy-token-endpoint-authentication

`x-speakeasy-token-endpoint-authentication` appears on security schemes. Its value is a string. Used by a single provider across 19 OpenAPI documents. It sits in the `x-speakeasy-` namespace, so its meaning is defined by speakeasy tooling rather than by OpenAPI. Observed values include `client_secret_basic`. Consistent with sdk & code generation — this is inferred from where the key appears and what it carries, not from any published definition.

SDK & code generation x-speakeasy- 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.
19 occurrences
19 documents
1 providers
vendor-named

Where it appears

Location in the documentOccurrences
securityScheme 19

What its value looks like

Value shapeOccurrences
string19

Observed values

Sampled from the specifications, most frequent first.

client_secret_basic

Providers publishing it

All 1.

dwolla

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.