typescript-authenticationlisted

# Authenticating an APIMatic TypeScript SDK client **This API declares at least one security scheme.** APIMatic surfaces each one as an **optional credentials property on the config object**; set the one(s) your API uses when constructing the client (see `typescript-client-initialization`). To see which schemes a specific SDK accepts, read the **credentials properties on the `Configuration` interface in `src/configuration.ts`** — they are generated per-API and are the source of truth both for which schemes exist and for the exact inner field names of each. The property name is generated too and is **not** always the scheme name from the spec (a scheme named `APIKeyHeader` can surface as `customHeaderAuthenticationCredentials`), so read it rather than deriving it. `doc/auth/*.md` gives the same information as a table plus a working snippet, and names the property in its "Auth credentials can be set using `...` object in the client" line. A **custom** scheme is the exception to all of that: its property is typed `any`, it gets no `doc/auth` page, and its real shape and behaviour live in the generated `customAuthenticationProvider` in `src/authentication.ts` — the one part of that file that is not just a re-export of the shared `@apimatic` auth adapters. See [reference.md](reference.md). **Standing rule: pass credentials as the scheme's object literal.** Even a single-value scheme is `{ <fieldName>: '...' }`. An SDK may additionally carry a deprecated top-level bare-string f