> For clean Markdown content of this page, append .md to this URL. For the complete documentation index, see https://buildwithfern.com/learn/llms.txt. ## Playground-only authentication descriptions api-reference You can now add auth instructions that appear only in the API Explorer, such as where to generate a token, without changing the Authorization description in your API Reference. Set `x-fern-playground-description` on a security scheme in your OpenAPI spec, or `playground-docs` on an auth scheme in a Fern Definition. The text renders as an info callout beneath the matching auth input and supports links, inline code, and paragraphs. Read the docs