notify action in automation gives error : "Error in describing action: Cannot read properties of undefined (reading 'description_placeholders')"

[IKIKN]

Checklist

• I have updated to the latest available Home Assistant version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in safe mode to rule out problems with unsupported custom resources.

Describe the issue you are experiencing

Hi,

Since upgrading the core to the latest version, all of my automations that send a notification display an error in the GUI (and endlessly try to reload in the background) :

The error says. : "Error in describing action: Cannot read properties of undefined (reading 'description_placeholders')"

This is the YAML that gives an error :

- action: notify.NOTIFICATION_GROUP data: message: Nope

And this is my NOTIFICATION_GROUP in the configuration.yaml file:

`# Notifications group
notify:

• platform: group
  name: NOTIFICATION_GROUP
  description": "Fake action for testing"
  services:
  • action: mobile_app_iphone
  • action: mobile_app_mac_mini
  • action: mobile_app_macbook_air`

I think the error was introduced by this commit: ae3a405

The exact piece of code that causes the error is this one :

I cannot even edit this block in YAML anymore, this completely breaks the interface, the only way to update my automation is to edit the YAML of the whole automation.

What can I do?

Thanks

Describe the behavior you expected

The code should nullcheck the parts of this.hass.services[domain][serviceName].description_placeholders instead of assuming that nothing is null in there.

Steps to reproduce the issue

1. Create a notify group
2. Send a notification with an automation

What version of Home Assistant Core has the issue?

core-2025.12.1

What was the last working version of Home Assistant Core?

No response

In which browser are you experiencing the issue?

Not browser-related

Which operating system are you using to run this browser?

Not OS-related

State of relevant entities

Problem-relevant frontend configuration

JavaScript errors shown in your browser console/inspector

Additional information

No response

[karwosts]

This is a valid bug but I will point out that the line of code you cited is not the reason why it's uneditable. That code only generates the text in the item header, but even after fixing that it doesn't fix the broken editor.