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:

0a. Gate: live state before config

Before proposing or editing automations, scripts, scenes, or dashboards, read repo-local HA guidance and query live state through configured integrations or approved helpers. Filter at source to relevant entity_id, state, and friendly_name; never dump all states or print token/secret contents. If live state is unreachable, report the blocker instead of guessing.

0b. 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.

Scenario	Mode
Motion light with timeout	restart
Sequential processing (door locks)	queued
Independent per-entity actions	parallel
One-shot notifications	single

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

Anti-pattern	Use instead	Why	Reference
condition: template with float > 25	condition: numeric_state	Validated at load, not runtime	references/automation-patterns.md#native-conditions
wait_template: "{{ is_state(...) }}"	wait_for_trigger with state trigger	Event-driven, not polling; waits for change (see references/safe-refactoring.md#trigger-restructuring for semantic differences)	references/automation-patterns.md#wait-actions
device_id in triggers	entity_id (or device_ieee for ZHA)	device_id breaks on re-add	references/device-control.md#entity-id-vs-device-id
mode: single for motion lights	mode: restart	Re-triggers must reset the timer	references/automation-patterns.md#automation-modes
enabled: false as a top-level key in automations.yaml	automation.turn_off (temporary) or entity registry disable (permanent)	Not a valid top-level key — rejected during schema validation; automation loads as unavailable	references/automation-patterns.md#disabling-automations
Template sensor for sum/mean	min_max helper	Declarative, handles unavailable states	references/helper-selection.md#numeric-aggregation
Template binary sensor with threshold	threshold helper	Built-in hysteresis support	references/helper-selection.md#threshold
Renaming entity IDs without impact analysis	Follow references/safe-refactoring.md workflow	Renames break dashboards, scripts, scenes, Config-Entry data, and storage dashboards silently	references/safe-refactoring.md#entity-renames
Renaming members of Config-Entry-based groups (UI groups) without updating membership	Update group membership via Options Flow after the registry rename	The entity registry rename does not update options.entities in the Config Entry — group silently breaks	references/safe-refactoring.md#config-entry-groups
Renaming entities used by Config-Entry integrations (Better/Generic Thermostat, Min/Max, Threshold) without patching Config-Entry data	Scan and patch core.config_entries data+options fields	These integrations store entity_ids in Config Entry — not updated by entity registry renames	references/safe-refactoring.md#config-entry-data--blind-spots-for-entity-registry-renames
template: sensor/binary sensor in YAML	Template Helper (UI or config flow API)	Requires file edit and config reload; harder to manage	references/template-guidelines.md
Editing .storage/ files or other HA internal state directly	Use the HA REST/WebSocket API to manage state and config entries	.storage/ files are HA's internal state database; direct edits bypass validation, risk corruption, and can be silently overwritten by HA	—
Writing raw YAML to configuration.yaml by hand for YAML-only integrations	Use managed YAML config editing with backup and validation	Unmanaged writes risk syntax errors, have no backup, and skip check_config — managed editing provides all three	references/yaml-only-integrations.md
Generating YAML snippets for automations/scripts/scenes	Use the HA config API to create automations/scripts programmatically	API calls validate config, avoid syntax errors, and don't require manual file edits or restarts	references/automation-patterns.md, references/examples.yaml
Telling user to edit configuration.yaml for integrations	Direct user to Settings > Devices & Services in the HA UI	Most integrations are UI-configured; YAML integration config is rare and integration-specific	—
Referring to HA "add-ons"	Use the term "Apps"	HA renamed add-ons to Apps in 2026.2 — "Apps are standalone applications that run alongside Home Assistant"	—
vacuum.send_command with vendor room IDs	vacuum.clean_area with HA area_id (if segments are mapped)	Uses native HA areas, works across integrations — but requires segment-to-area mapping in entity settings first	references/device-control.md#vacuum-control
Using color_temp (mireds) in light service calls	Use color_temp_kelvin	The color_temp parameter was removed in 2026.3; only Kelvin is supported	references/device-control.md#lights
Person/Device Tracker entered_home/left_home device triggers or is_home/is_not_home conditions	state trigger to: home / to: not_home, or state condition	These were removed in 2026.5 — state triggers and conditions are the correct replacements	references/automation-patterns.md#presence-and-person-triggers-and-conditions-removed-in-20265
Registering callbacks or calling self.turn_on()/self.get_state() in __init__()	Register everything in initialize()	Plugin connection not established during __init__ — calls fail silently	references/appdaemon.md#app-structure-and-lifecycle
Calling run_in on repeated triggers without cancelling the previous handle	cancel_timer(self._off_handle) before each new run_in	Every trigger stacks an independent timer — devices toggle unpredictably	references/appdaemon.md#scheduling-and-timers
Storing persistent state in instance variables	Use HA input_number, input_boolean, or input_text helpers	Instance variables reset on app reload or daemon restart	references/appdaemon.md#state-management-and-inter-app-communication
Hardcoding entity IDs inside the class body	Pass entity IDs via self.args in apps.yaml	Hardcoded IDs prevent reuse and require code edits per installation	references/appdaemon.md#appsyaml-configuration

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Reference Files

Read these when you need detailed information:

File	When to read	Key sections
references/safe-refactoring.md	Renaming entities, replacing helpers, restructuring automations, or any modification to existing config	#universal-workflow, #entity-renames, #helper-replacements, #trigger-restructuring, #config-entry-data--blind-spots-for-entity-registry-renames, #storage-mode-dashboards-storagelovelace
references/automation-patterns.md	Writing triggers, conditions, waits, variables, or choosing automation modes; capturing action responses; documenting/annotating steps; disabling automations	#native-conditions, #trigger-types, #wait-actions, #automation-modes, #continue-on-error, #stopping-a-sequence, #variables, #capturing-action-responses, #repeat-actions, #ifthen-vs-choose, #parallel-actions, #trigger-ids, #documenting-automations--scripts, #disabling-automations
references/helper-selection.md	Deciding whether to use a built-in helper vs template sensor	#how-helpers-are-created, #menu-based-helpers, #numeric-aggregation, #rate-and-change, #time-based-tracking, #counting-and-timing, #scheduling, #entity-grouping, #probabilistic-inference, #data-smoothing, #random-values, #climate-control, #domain-conversion, #template-helpers, #decision-matrix
references/template-guidelines.md	Confirming templates ARE appropriate for a use case	#when-templates-are-appropriate, #when-to-avoid-templates, #template-sensor-best-practices, #common-patterns, #error-handling
references/yaml-only-integrations.md	Creating or editing YAML-only integrations that have no config flow (e.g. command_line, platform-based mqtt, rest)	#yaml-only-integration-types, #post-edit-actions
references/device-control.md	Writing service calls, Zigbee button automations, or using target:	#entity-id-vs-device-id, #service-calls-best-practices, #zigbee-buttonremote-patterns, #domain-specific-patterns
references/scenes.md	Authoring or activating scenes; snapshot/restore patterns; snapshot-vs-script distinction	#scene-config-shape, #activating-a-scene, #snapshot--restore-scenecreate, #apply-states-without-storing-sceneapply
references/dashboard-guide.md	Designing or modifying Lovelace dashboards — layout, view types, strategies, sections, cards, badges, CSS styling, HACS	#dashboard-structure, #view-types, #dashboard-strategies, #built-in-cards, #features, #badges, #custom-cards, #css-styling, #common-pitfalls
references/dashboard-cards.md	Looking up available card types or fetching card-specific documentation	—
references/domain-docs.md	Looking up integration or domain documentation for service calls, entity attributes, or configuration	—
references/examples.yaml	Need compound examples combining multiple best practices	—
references/appdaemon.md	AppDaemon apps: when to use vs. native HA, app structure, service calls, scheduling, error handling, safe refactoring impact	—