[Bug] Modern 'template:' integration (sensor/switch) fails silently or with parser errors in Core 2025.5.3

[Jolo-Jan]

The problem

The problem

The modern template: integration (introduced to replace legacy top-level sensor: - platform: template, etc.) does not seem to work correctly in Home Assistant Core 2025.5.3.

Attempts to create template: - switch: entities either result in parser errors ('value_template' is an invalid option for 'template') even with seemingly correct YAML, or they fail silently without creating entities, even when the configuration check passes and no errors are logged.

Even a simple template: - sensor: entity fails to be created (silently, without errors) when placed directly in configuration.yaml.

Environment

• Home Assistant Core: 2025.5.3
• Installation Type: Home Assistant OS
• Supervisor: 2025.05.1
• Operating System: 6.12.23-haos
• Hardware: Dell Wyse 5070 | Intel J4105 | 8GB RAM | 512GB SSD
• default_config: is enabled.

Steps to Reproduce

We tried several methods to create template entities:

1. Template Switch directly in configuration.yaml:

• Code used:

  template:
    - switch:
        - name: "Garten Schalter 1 (Icon)"
          value_template: "{{ is_state('switch.garten_schalter_1', 'on') }}"
          turn_on:
            service: switch.turn_on
            target:
              entity_id: switch.garten_schalter_1
          turn_off:
            service: switch.turn_off
            target:
              entity_id: switch.garten_schalter_1
          icon_template: >-
            {% if is_state('switch.garten_schalter_1', 'on') %}
              mdi:water-pump
            {% else %}
              mdi:water-pump-off
            {% endif %}
          unique_id: garten_schalter_1_template_icon_test

• Result: Invalid config for 'template' ... 'value_template' is an invalid option for 'template', check: switch->0->value_template. This error points to a valid key as invalid.

2. Template Switch via !include templates.yaml:

• configuration.yaml: template: !include templates.yaml
• templates.yaml: (Content as above, starting with - switch:)
• Result: Config check passed, but after restart, the same error appeared in the logs, and the entity was not created.

3. Template Sensor ONLY via !include templates.yaml:

• configuration.yaml: template: !include templates.yaml
• templates.yaml:

  - sensor:
      - name: "Test Template Sensor"
        state: "{{ now().isoformat() }}"
        unique_id: test_template_sensor_12345

• Result: Config check passed, restart caused no errors, but the sensor entity was not created.

4. Template Sensor ONLY directly in configuration.yaml:

• configuration.yaml:

  template:
    - sensor:
        - name: "Test Template Sensor Direkt"
          state: "{{ now().isoformat() }}"
          unique_id: test_template_sensor_12345_direct

• Result: Config check passed, restart caused no errors, but the sensor entity was still not created.

Expected behavior

Template entities (sensors, switches) defined using the modern template: integration structure should be created successfully when the configuration is valid.

Actual behavior

Template entities are not created. Either the configuration fails with incorrect parser errors, or it fails silently after a restart, even when the configuration check passes and no errors are logged.

Logs

The key error when using switch is:

Invalid config for 'template' at <file>, line <X>: 'value_template' is an invalid option for 'template', check: switch->0->value_template
Invalid config for 'template' at <file>, line <Y>: 'icon_template' is an invalid option for 'template', check: switch->0->icon_template

When using only the sensor (Attempts 3 & 4), no errors appeared in the logs, but the entity was not created.

Additional information

This behaviour seems to indicate a fundamental issue with how the template: integration loads or parses configurations in Core 2025.5.3, affecting both !include and direct configuration, and both switch and sensor platforms.

What version of Home Assistant Core has the issue?

2025.5.3

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant OS

Integration causing the issue

Template

Link to integration documentation on our website

No response

Diagnostics information

No response

Example YAML snippet

# In configuration.yaml
template:
  - sensor:
      - name: "Test Template Sensor Direkt"
        state: "{{ now().isoformat() }}"
        unique_id: test_template_sensor_12345_direct

Anything in the logs that might be useful for us?

when trying to configure a 'template: - switch:', the following error appears, incorrectly marking valid keys as invalid:

Invalid config for 'template' at <file>, line <X>: 'value_template' is an invalid option for 'template', check: switch->0->value_template
Invalid config for 'template' at <file>, line <Y>: 'icon_template' is an invalid option for 'template', check: switch->0->icon_template

Crucially, when trying to configure *only* a simple 'template: - sensor:', **NO errors** appear in the logs, but the entity is still not created.

Additional information

No response

[Petro31]

All your attempted configurations are incorrect and the errors are telling you that.

For legacy:

switch:
  - platform: template
    switches:
      - friendly_name: "Garten Schalter 1 (Icon)"
        value_template: "{{ is_state('switch.garten_schalter_1', 'on') }}"
        turn_on:
          service: switch.turn_on
          target:
            entity_id: switch.garten_schalter_1
        turn_off:
          service: switch.turn_off
          target:
            entity_id: switch.garten_schalter_1
        icon_template: >-
          {% if is_state('switch.garten_schalter_1', 'on') %}
            mdi:water-pump
          {% else %}
            mdi:water-pump-off
          {% endif %}
        unique_id: garten_schalter_1_template_icon_test

for modern.

template:
  - switch:
      - name: "Garten Schalter 1 (Icon)"
        state: "{{ is_state('switch.garten_schalter_1', 'on') }}"
        turn_on:
          service: switch.turn_on
          target:
            entity_id: switch.garten_schalter_1
        turn_off:
          service: switch.turn_off
          target:
            entity_id: switch.garten_schalter_1
        icon: >-
          {% if is_state('switch.garten_schalter_1', 'on') %}
            mdi:water-pump
          {% else %}
            mdi:water-pump-off
          {% endif %}
        unique_id: garten_schalter_1_template_icon_test

You attempted modern configuration and the error told you what was invalid:

Invalid config for 'template' at <file>, line <X>: 'value_template' is an invalid option for 'template', check: switch->0->value_template
Invalid config for 'template' at <file>, line <Y>: 'icon_template' is an invalid option for 'template', check: switch->0->icon_template

value_template should be state
icon_template should be icon

[Jolo-Jan]

Hi Petro31, Thank you so much for looking into this and for your incredibly helpful comment! You were absolutely right. It seems I completely overlooked the change from value_template to state when using the modern template integration format. That explains why none of my attempts were working. I sincerely apologize for my mistake and for taking up your time with a bug report for what turned out to be a configuration error on my end. I really appreciate you pointing out the correct syntax. I will test this configuration as soon as possible and am confident that this will resolve the issue. Thanks again for your help and expertise! Best regards, Jan

…

________________________________ Von: Petro31 ***@***.***> Gesendet: Montag, 26. Mai 2025 14:02 Bis: home-assistant/core ***@***.***> Cc: Jolo-Jan ***@***.***>; Author ***@***.***> Betreff: Re: [home-assistant/core] [Bug] Modern 'template:' integration (sensor/switch) fails silently or with parser errors in Core 2025.5.3 (Issue #145567) [https://avatars.githubusercontent.com/u/35082313?s=20&v=4]Petro31 left a comment (home-assistant/core#145567)<#145567 (comment)> All your attempted configurations are incorrect. For legacy: switch: - platform: template switches: - friendly_name: "Garten Schalter 1 (Icon)" value_template: "{{ is_state('switch.garten_schalter_1', 'on') }}" turn_on: service: switch.turn_on target: entity_id: switch.garten_schalter_1 turn_off: service: switch.turn_off target: entity_id: switch.garten_schalter_1 icon_template: >- {% if is_state('switch.garten_schalter_1', 'on') %} mdi:water-pump {% else %} mdi:water-pump-off {% endif %} unique_id: garten_schalter_1_template_icon_test for modern: template: - switch: - name: "Garten Schalter 1 (Icon)" state: "{{ is_state('switch.garten_schalter_1', 'on') }}" turn_on: service: switch.turn_on target: entity_id: switch.garten_schalter_1 turn_off: service: switch.turn_off target: entity_id: switch.garten_schalter_1 icon_template: >- {% if is_state('switch.garten_schalter_1', 'on') %} mdi:water-pump {% else %} mdi:water-pump-off {% endif %} unique_id: garten_schalter_1_template_icon_test — Reply to this email directly, view it on GitHub<#145567 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BRVBF6WTC26BOENBCYEKUCD3AL7EJAVCNFSM6AAAAAB5273QU6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDSMBZGQ4TCNRQG4>. You are receiving this because you authored the thread.