Additional custom attributes for all devices/entities of a domain?

Is there a way to conditionally add additional custom attributes for all devices/entities of a domain?

For example, I want to add a custom attribute called friendly_color_temp for light domain type.

Closest I found is Light Template and Customize Domain but neither really do what I want.

I am looking to do something like:

  customize_domain:
    light:
      icon: mdi:home
      friendly_color_temp:
        {% if is_state('on') %}
          {% if state_attr('color_temp') %}
            {% color_temp_in_kelvin = 1000000/color_temp %}
              {% if color_temp_in_kelvin < 3000 %>
                Warm White
              ...

My question is that I have special computed attributes for each device and I want to reference the values easily when I use them in cards, node-red, etc.

Hi there, do you find a way to do this ? :slight_smile:

Also interested on knowing this

No news here ?