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type: entityconfidence: highupdated: 2026-08-05sources: 1

Overview

The Home Assistant gatekeeper lets a Gadget read state from a connected Home Assistant (HA) instance, call services on devices (lights, thermostats, locks, etc.), edit Lovelace dashboards, render templates, and read history — all mediated through the standard Gadgets approval queue.

Characteristics

  • Auth: Home Assistant long-lived access token (LLAT) + instance URL, no OAuth flow — chosen because each HA instance has a different URL (no central directory), LLATs don't expire (10-year default lifetime), it's the pattern users already know from other HA tools, and it works for both Nabu Casa Cloud and self-hosted/LAN users. The user pastes URL + LLAT into a form; the gatekeeper validates via GET /api/ and stores both in a per-user Durable Object.
  • Reachability: on Cloudflare-hosted deployments, HA must be publicly reachable (Nabu Casa, Cloudflare Tunnel, port-forwarding). On self-hosted (workerd) deployments, LAN addresses like http://homeassistant.local:8123 or http://192.168.x.x:8123 work directly — the intended setup for same-network deployments.
  • Five resource granularities: Whole instance (every area/device/entity/dashboard/service), Area (one room's devices/entities), Label (all entities with a given HA label), Device (one physical device and its entities), Entity (one light/sensor/switch/etc.) — each with its own configurator picker UI.
  • TypeScript API: bindings expose HomeAssistantSession (whole-instance), Area, Label, Device, or Entity depending on granularity. Example:
    const areas = await session.listAreas();
const light = await session.getEntity("light.kitchen");
await light.turnOn({ brightness: 200 });
const state = await light.getState();  // reflects simulated post-write state
const livingRoom = await session.getArea("living_room");
await livingRoom.callService("light", "turn_off");
const temp = await session.renderTemplate("{{ states('sensor.outside_temp') | float }}");
const dashboard = await session.getDashboard("lovelace");
await dashboard.saveConfig(dashboardConfig);
  • Approval & simulation: every read calls authorizeObservation, every write goes through submitAction; writes do not execute against HA until approved. Until approval, reads reflect a simulated post-action world (e.g. getState() shows "on" right after turnOn()) — but simulation predicts final states only, with no transition timing, and leaves state untouched for unrecognized service calls (custom integrations, scenes, scripts, templates).
  • Not yet implemented (Phase 2): caching (every read is a fresh registry fetch) and hooks/push events (setHook is a no-op; WebSocket subscribe_events/subscribe_entities would enable a HomeAssistantHook).
  • Implementation notes: service calls go through HA's WebSocket API (call_service), not the REST endpoint, for full target-shape support across area/label/floor targets; every action gets an integer id from a per-DO counter, stored under pending:<id> for read-time simulation; malformed action bodies fail synchronously with a corrected-call suggestion.

How to Use

  1. In a Gadget's Connections UI, connect a Home Assistant account by pasting the instance URL and a long-lived access token (generate one in HA's own UI).
  2. Choose a resource granularity to grant: whole instance, an area, a label, a device, or a single entity, using the matching configurator picker.
  3. Use the TypeScript Session API (see src/types.d.ts for full method list and @example blocks) to read state, call services, render templates, or edit dashboards; writes queue for approval before taking effect on the real HA instance.

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