Home Assistant Best Practices

Core principle: Use native Home Assistant constructs wherever possible. Templates bypass validation, fail silently at runtime, and make debugging opaque.

Decision Workflow

Follow this sequence when creating any automation:

0. Gate: modifying existing config?

If your change affects entity IDs or cross-component references — renaming entities, replacing template sensors with helpers, converting device triggers, or restructuring automations — read references/safe-refactoring.md first. That reference covers impact analysis, device-sibling discovery, and post-change verification. Complete its workflow before proceeding.

Steps 1-5 below apply to new config or pattern evaluation.

1. Check for native condition/trigger

Before writing any template, check references/automation-patterns.md for native alternatives.

Common substitutions:

• {{ states('x') | float > 25 }} → numeric_state condition with above: 25
• {{ is_state('x', 'on') and is_state('y', 'on') }} → condition: and with state conditions
• {{ now().hour >= 9 }} → condition: time with after: "09:00:00"
• wait_template: "{{ is_state(...) }}" → wait_for_trigger with state trigger (caveat: different behavior when state is already true — see references/safe-refactoring.md#trigger-restructuring)

2. Check for built-in helper or Template Helper

Before creating a template sensor, check references/helper-selection.md.

Common substitutions:

• Sum/average multiple sensors → min_max integration
• Binary any-on/all-on logic → group helper
• Rate of change → derivative integration
• Cross threshold detection → threshold integration
• Consumption tracking → utility_meter helper

If no built-in helper fits, use a Template Helper — not YAML. Create it via the HA config flow (MCP tool or API) or via the UI: Settings → Devices & Services → Helpers → Create Helper → Template. Only write template: YAML if explicitly requested or if neither path is available.

3. Select correct automation mode

Default single mode is often wrong. See references/automation-patterns.md#automation-modes.

4. Use entity_id over device_id

device_id breaks when devices are re-added. See references/device-control.md.

Exception: Zigbee2MQTT autodiscovered device triggers are acceptable.

5. For Zigbee buttons/remotes

• ZHA: Use event trigger with device_ieee (persistent)
• Z2M: Use device trigger (autodiscovered) or mqtt trigger

See references/device-control.md#zigbee-buttonremote-patterns.

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Critical Anti-Patterns

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Reference Files

Read these when you need detailed information: