Are you describing directly in the OpenAPI specification?

Yes, the OpenAPI specification allows describing APIs directly in YAML or JSON format, where paths, methods, parameters, data schemas, and responses are detailed. It is a convenient way to document and standardize APIs, as well as generate client code and tests. For example, an endpoint can be described as follows:

paths:
  /users:
    get:
      summary: Get a list of users
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/User'