Build a Smart Home Automation, Then Watch a Day Unfold

Home Assistant concepts, accurately

• Entities are the atoms: light.living_room, binary_sensor.front_door, climate.house. Everything you automate is an entity with a state.
• Automations = trigger + condition + action, and they wait for events. Scripts are just the action part, callable on demand. Scenes are snapshots of entity states ("movie night") you can apply instantly.
• Triggers fire on change (state, time, sun elevation, MQTT, webhooks). Conditions are checked at fire-time and silently abort if false — that's why "motion → light" plus a sun below horizon condition doesn't blind you at noon.
• The sun integration exposes sunrise/sunset as triggerable events — used by this demo's "at sunset" trigger.

Why config-as-code beats SSH guesswork

Home Assistant configuration is YAML. Editing it live over SSH works until a typo breaks reload at 11pm. Treating it as code — in git, edited by tools (like a Claude Code skill driving hass-cli or MCP) — gives you diffs, review, rollback, and reproducible dashboards:

automation:
  - alias: "Evening motion light"
    trigger:
      - platform: state
        entity_id: binary_sensor.living_motion
        to: "on"
    condition:
      - condition: sun
        after: sunset
    action:
      - service: light.turn_on
        target: {entity_id: light.living_room}

Every rule you build above maps 1:1 onto this structure — that is the whole mental model.