fern write definition

fern write-definition will convert your OpenAPI specification into a Fern Definition. You'll see a new folder called definition created.

When successfully executed, this command will not produce any output, indicating it has run without issues.


When you have an openapi folder and a definition folder, Fern defaults to reading your OpenAPI spec. Remove the openapi folder if you'd like to use your Fern Definition as an input to Fern's generators.