Example.pm

package MyApp;

use Catalyst 'OpenAPI';

__PACKAGE__->config(
  'Plugin::OpenAPI' => {
    # global settings;
  },
);

package MyApp::Controller::User;

use MyApp::Controller;

sub users
  :openAPI({
    summary: 'Returns worlds by name.',
    operationId: 'getWorlds',
    parameters: [
      {
        in: 'query',
        name: 'worldName',
        required: true,
        type: 'string'
      }
    ],
    responses: {
      200: {
        description: 'A list of worlds that match the requested name.',
        schema: {
          type: 'array',
          items: {
            $ref: '#/definitions/World'
          }
        }
      },
      default: {
        description: 'An error occurred',
        schema: {
          additionalProperties: true
        }
      }
    }
  }) ($self, $c) {
  ## Stuff to handle the endpoint
}

sub users_200 :OpenAPI { ... }
sub users_default :OpenAPI { ... }

__PACKAGE__->meta->make_immutable(1);

https://www.npmjs.com/package/express-openapi
https://docs.nestjs.com/recipes/swagger