MQTT auto discovery - why device name = "null"

Max77 · February 22, 2026, 10:03am

Hi.
Who knows how to set the “name” attribute for an mqtt device when creating it? It set to null, and the passed name attribute is written in the entity_registry to the “original_name” attribute.
For example, my auto-detection code:

{
    "dev": {
        "ids": "Light12_Dining",
        "name": "Light12/Dining",
    },
...
    "cmps": {
        "Light12_Dining4": {
            "p": "light",
            "uniq_id": "light.Light12_Dining4",
            "def_ent_id": "light.Light12_Dining4",
            "name": "Dining",
...
        }
    }
}

In the registry it looks like this:
… “name”: null,… “original_name”: “Dining”

In HA, the device is displayed with a name, but in order to transfer information about it to external integration, I have to manually fill in the Name.

Sir_Goodenough · February 22, 2026, 7:08pm

The ‘/’ might be messing with you.

Here’s some examples from a blueprint of mine using a lot of MQTT discovery.

github.com/SirGoodenough/HA_Blueprints

Automations/Octoprint_Additional_Buttons_Helper.yaml

abfe45f22


      
                    "sw": "{{ sw }}",
                    "hw": "{{ hw }}",
                    "cu": "{{ cu }}"
                  },
                  "name": "{{ h_bname }}",
                  "uniq_id": "{{ h_uniq_id }}",
                  "ic": "{{ h_ic }}",
                  "cmd_t": "{{ h_cmd_t }}",
                  "pl_prs": "{{ h_pl_prs }}"
                }
          - alias: Bed Level Button Create
            action: mqtt.publish
            data:
              "topic": "{{ bl_c_topic }}"
              "retain": true
              "payload": >
                { "~": "{{ printer_topic }}",
                  "avty_t": "{{ avty_t }}",
                  "pl_avail": "{{ pl_avail }}",
                  "pl_not_avail": "{{ pl_not_avail }}",
                  "dev": {