Something has broken an agent response with TTS for automation

Configuration
1

I am using an automation to get data and process back for agent response to then feed to tts.piper and play it on an Apple HomePod Mini. This worked until recently and I am running the latest everything but here is what I am getting in the errors:

Executed: April 28, 2026 at 6:30:04 AM
Error: ('failed to init decoder', -1)
Result:
params:
  domain: tts
  service: speak
  service_data:
    cache: false
    media_player_entity_id: media_player.great_room_2
    message: >-
      Today is Tuesday April 28, 2026. The weather is rainy across the area.
      Today's high temperature will be 76 degrees Fahrenheit and tonight's low
      temperature will be 63 degrees Fahrenheit. There is a chance of rain with
      a probability of 48 percent.
    options:
      voice: en_GB-alan-medium
    entity_id:
      - tts.piper
  target:
    entity_id:
      - tts.piper
running_script: false

Here is how I am calling this action:

action: tts.speak
metadata: {}
data:
  cache: false
  media_player_entity_id: media_player.great_room_2
  options:
    voice: en_GB-alan-medium
  message: "{{ agent.response.speech.plain.speech }}"
target:
  entity_id: tts.piper

Trying to figure out what the issue is and appreciate any insight. Thanks!

2

That says Piper failed to decode the message you sent - the problem is there. How do you have piper setup. Id check it’s log for more info…

3

I don’t think that is fully the issue as I do this fine with a sample action like this and it works on that same device.

Also piper has NO errors.

action: tts.speak
target:
  entity_id: tts.piper
data:
  cache: true
  media_player_entity_id: media_player.great_room_2
  message: Test
  options:
    voice: en_GB-alan-medium
4

I’m getting (‘failed to init decoder’, -1) on playing tts to HomePods on automations that were working for months as well. Started happening in the last week or so. I’m on ha os, core 2026.4.4. I’m pretty sure the issue started after that update with no changes. Similar issue to you where certain tts will work and other will fail. Hoping it’s just a bug that needs fixing. I may try to revert to an earlier version for testing if possible. I’ve not tried that before.

5

For what it’s worth I reverted back to 2026.4.3 and it is working fine again. I think there is some bug in 2026.4.4. Not sure if that’s the same for you but it may be worth a try. For HA OS from terminal I just did ha core update --version 2026.4.3, that did the downgrade.