Home Assistant Scripting: Automate Tomorrow, Today

Welcome, fellow smart‑home enthusiasts! If you’ve ever dreamed of waking up to the aroma of freshly brewed coffee, having your lights dance in sync with your favorite playlist, or simply letting Home Assistant (HA) handle the boring bits while you binge‑watch your shows, you’re in the right place. In this post we’ll walk through the fundamentals of HA scripting and automation rules, sprinkle in some best‑practice tips, and end with a practical example that you can copy‑paste right into your automations.yaml. Let’s get automating!

What Are Scripts and Automations?

Scripts are reusable blocks of actions you can trigger manually, via services, or from other automations. Think of them as a recipe you can call whenever you want.

Automations are event‑driven. They consist of a trigger, optional condition(s), and one or more actions. Whenever the trigger fires, HA evaluates the conditions; if they pass, the actions execute.

In short:

• Scripts: “Do this when I say so.”
• Automations: “Do this when something happens.”

Getting Started: File Structure

Home Assistant stores configurations in config/. Two files are key for this guide:

1. scripts.yaml – holds all your script definitions.
2. automations.yaml – holds all your automation definitions.

If you haven’t yet, add them to configuration.yaml:

scripting: !include scripts.yaml
automation: !include automations.yaml

Now you’re ready to roll!

Building a Simple Script

Let’s create a script that turns on the living‑room lights, plays your favorite playlist, and sets the thermostat to 22°C. Open scripts.yaml and add:

turn_on_living_room:
 alias: "Living Room Warm‑Up"
 description: Turns on lights, plays music, and sets temperature.
 mode: single
 sequence:
  - service: light.turn_on
   target:
    entity_id: light.living_room_main, light.living_room_ambient
   data:
    brightness_pct: 70
  - service: media_player.play_media
   target:
    entity_id: media_player.spotify_living_room
   data:
    media_content_type: music
    media_content_id: "spotify:user:your_spotify_user:playlist:37i9dQZF1DXcBWIGoYBM5M"
  - service: climate.set_temperature
   target:
    entity_id: climate.living_room_thermostat
   data:
    temperature: 22

Key points:

• alias gives a human‑readable name.
• mode: single prevents overlapping runs.
• Use target: instead of the older entity_id: for cleaner syntax.

Crafting an Automation

Now let’s automate that script so it runs at sunset and when you say “Hey Google, start my evening.” Create the following in automations.yaml:

- alias: "Evening Routine"
 description: Starts the living‑room warm‑up at sunset and on voice command.
 trigger:
  - platform: sun
   event: sunset
  - platform: voice_command
   command_type: text
   command: "start my evening"
 condition:
  - condition: state
   entity_id: input_boolean.evening_mode
   state: "on"
 action:
  - service: script.turn_on_living_room

Why the input_boolean.evening_mode?

• It lets you toggle the routine on or off from the UI.
• Adding a condition keeps your house from over‑automating during the day.

Best Practices for Automations

• Use unique IDs: Add id: evening_routine to avoid duplicates after reloads.
• Keep triggers simple: Complex logic goes in conditions or actions.
• Leverage templates: Use {{ now().strftime("%H:%M") }} for time‑based conditions.
• Test incrementally: Create a single trigger, see it work, then add more.

Advanced Scripting: Conditional Logic

Suppose you want the lights to dim if it’s already dark. Add a choose action:

- service: script.turn_on_living_room
 data:
  brightness_pct: <?= state_attr('light.living_room_main', 'brightness') default(255) / 2 ?>

But that looks messy. HA’s choose block is cleaner:

sequence:
 - choose:
   - conditions:
     - condition: numeric_state
      entity_id: sensor.lux_living_room
      below: 50
    sequence:
     - service: light.turn_on
      target:
       entity_id: light.living_room_main
      data:
       brightness_pct: 30
   default:
    - service: light.turn_on
     target:
      entity_id: light.living_room_main
     data:
      brightness_pct: 70

Now the lights automatically adapt to ambient light.

Using Templates for Dynamic Actions

Templates let you pull in sensor data or calculate values on the fly. For example, to set the thermostat based on outside temperature:

- service: climate.set_temperature
 target:
  entity_id: climate.living_room_thermostat
 data:
  temperature: <?= (states('sensor.outdoor_temperature') float) + 2 ?>

Tip: Wrap your template in {{ }} for readability.

Debugging: How to See What’s Happening

When an automation fails, the log will often include a stack trace pointing to the offending line.

Performance Tips

• Avoid loops: Scripts that call themselves recursively can hang HA.
• Use delay sparingly: Over‑using delays can block the event loop.
• Prefer service_call over script.turn_on for simple one‑liners.
• Keep your YAML tidy: Use yamllint or the HA editor’s linting.

- id: good_night_routine

 alias: "Good Night Routine"

 description: Secure the house and save energy at night.

 trigger:

  - platform: sun

   event: sunset

  - platform: voice_command

   command_type: text

   command: "good night"

 condition:

  -