```ruby
require 'chef_zero/endpoints/cookbooks_base'

module ChefZero
  module Endpoints
    # /cookbooks
    class CookbooksEndpoint < CookbooksBase
      def get(request)
        json_response(200, format_cookbooks_list(request, all_cookbooks_list))
      end
    end
  end
end
```

Support cookbook_versions query param in /cookbooks
user
```ruby
require 'chef_zero/endpoints/cookbooks_base'

module ChefZero
  module Endpoints
    # /cookbooks
    class CookbooksEndpoint < CookbooksBase
      def get(request)
        if request.query_params['num_versions'] == 'all'
          num_versions = nil
        elsif request.query_params['num_versions']
          num_versions = request.query_params['num_versions'].to_i
        else
          num_versions = 1
        end
        json_response(200, format_cookbooks_list(request, all_cookbooks_list, {}, num_versions))
      end
    end
  end
end
```
assistant