Google Home MCP: what agent access means if you run Home Assistant

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Google started rolling out AI agent access to Google Home on September 16. The mechanism is Home MCP, a Model Context Protocol server Google runs at home.googleapis.com, which lets an agent list the devices in your home, read their current state, query past events and send commands. Google’s developer docs mark it Early Access and name a Google Home Premium Advanced subscription as a requirement. Press coverage puts that at $20 a month, in the United States, in US English.

Short version: there is nothing here to buy and nothing to change. Home MCP is a cloud API bolted onto an account you either already have or do not, and it does not move a single Nest device closer to working without the internet. If you run Home Assistant, the equivalent already exists, it runs on your own box, it is local push, and it needs no subscription unless you pick Home Assistant Cloud as your way in from outside. The one thing worth knowing is that Home MCP reads event history and, with separate consent, familiar-faces data, so if you have exposed Home Assistant entities into Google Home for voice, it is worth asking what an agent connected to your Google account can now see. I could not find a clear answer to that question.

What I verified, and what I haven’t. This is written from Google’s developer documentation, Google’s release notes and Home Assistant’s own docs, not from use. I haven’t run Home MCP and I don’t hold a Google Home Premium subscription.

Confirmed from Google’s own pages: the Early Access label, the server address, SSE transport and OAuth sign-in, the five tools an agent gets, the Premium Advanced requirement, the Google Cloud project and OAuth setup steps, the separate consent needed for familiar faces, that the service prohibits sensitive actions such as unlocking doors, the September 16 rollout start, and Google’s wording that agents can reach “all of the devices and event history in the Google Home ecosystem”.
Reported, not confirmed by a Google page I could fetch: that it is United States and US English only, and the “coming weeks” rollout.
I couldn’t find anywhere that says whether Home Assistant entities bridged into Google Home are in scope, what an agent can read from cameras beyond familiar faces, whether the lock restriction covers anything besides unlocking, whether access can be scoped to one room, what the rate limits are, or whether the rollout has finished.

Updated October 14, 2026: Google updated its developer page on September 21 with a known-issues list and a note that automations are not supported yet, Google’s release notes now confirm the start date and device wording first-hand, and Home Assistant rewrote its remote-access guidance. The sections below reflect all three.

What was announced

An agent that connects gets five tools, and they are worth reading as a list of permissions rather than features.

Tool	What the agent can do
`list_homes`	Retrieve the homes and structures on the account
`list_home_resources`	List devices, area layouts, traits, attributes and command schemas
`list_home_states`	Read real-time device connectivity and trait states
`run_home_actions`	Send parameterised commands to devices
`list_home_history`	Query past state changes and event logs over a time range

Google’s docs give manual setup instructions for three clients: Google Antigravity, Claude and OpenClaw. Press coverage names Hermes and ChatGPT too, though the docs I read do not carry setup steps for them.

What it needs

The requirements are heavier than the headlines suggest. Alongside the Premium Advanced subscription and an active Google Home setup, the documented path asks for a Google Cloud project with the Home API enabled and OAuth 2.0 credentials configured. That is a developer setup. I couldn’t find anywhere that says an ordinary Google Home user can skip those steps.

Familiar-faces data sits behind a second gate. Google’s docs say users must explicitly consent to that feature separately, must be a structure manager, and must have familiar-face detection enabled for each camera or doorbell.

What Google lists as unfinished

The developer page now carries a short known-issues list:

A bug lets Nest Aware Plus subscribers use Home MCP, although access is meant to be limited to Premium Advanced.
Some traits exposed to agents are marked experimental.
Google says you may see longer than expected delays.

Automations are not supported yet. Google says it plans to add creating and managing them in a future release. The page also asks you to tell other people in the household that your agent can control devices and access home data.

What it costs

Google Home Premium Advanced was announced in October 2025 at $20 a month or $200 a year. The Standard tier is $10 a month or $100 a year and does not qualify. Google AI Pro subscribers get Standard included and can add Advanced for $10 a month; Google AI Ultra subscribers get Advanced included.

What stays local, what doesn’t

None of this is local, and Google does not claim otherwise. The server lives at home.googleapis.com and an agent talks to it over the internet with an OAuth token. Your commands leave the house, land on Google’s servers and come back.

That is the same shape as everything else in a Google house, which is why my catalog ratings for Google hardware read the way they do. The Google Nest Thermostat reaches Home Assistant through Google’s cloud integration and is rated high cloud dependency. The Google TV Streamer 4K does better, mostly because it is a Thread border router and a local media target rather than a cloud sensor. Home MCP does not change either rating. It adds a new way to reach the same cloud.

Home Assistant already has this, locally

Home Assistant ships a Model Context Protocol Server integration. Its IoT class is local push, it runs on your instance, and an agent authenticates with OAuth or a long-lived access token.

	Google Home MCP	Home Assistant MCP Server
Where it runs	Google’s cloud, `home.googleapis.com`	Your Home Assistant instance
IoT class	Cloud API over OAuth	Local push
Cost	Google Home Premium Advanced	No subscription required; Home Assistant Cloud is one paid option for remote access
Scope	Google’s wording: all devices and event history in the Google Home ecosystem	Only entities you expose to it
Status	Early Access	Shipped integration

The scope row is the part I would pay attention to. Home Assistant’s docs say clients “can only control or provide information about entities that are exposed to them”, which is a per-entity decision you make. I couldn’t find an equivalent control anywhere in Google’s docs, or anywhere that says an agent’s access can be narrowed below the whole structure.

One caveat on the Home Assistant side: if the agent runs in the cloud, your instance has to be reachable from the internet, through Home Assistant Cloud or another remote access method. Home Assistant’s docs say Claude connects from the cloud even when you use Claude Desktop. Local push is not the same as effortless.

The question my Google fallback guide raises

My Home Assistant with Google Home fallback guide walks through exposing selected Home Assistant entities into the Google Home app so that voice commands work. Anyone who followed it has Home Assistant entities sitting inside a Google Home structure.

Google’s release notes say an agent can interact with “all of the devices and event history in the Google Home ecosystem”. TechCrunch reports that this includes “Works with Google Home” devices, and Home Assistant’s Google Assistant docs add the bridge through the Google Home app’s Works with Google Home screen. I couldn’t find anywhere that says Google treats bridged Home Assistant entities as in scope, but the wording leaves room for it. If they are, connecting an agent to your Google account hands it a control path into part of your Home Assistant setup. The lever you already hold is the entity exposure list in that integration.

Buy, wait or ignore

Home Assistant house. Ignore. You have a local MCP server already and this one costs $20 a month to reach devices you do not control from Google anyway. If you bridge entities into Google Home for voice, spend ten minutes reviewing which ones, which is worth doing regardless of this announcement.

Google Home or Nest house. Wait. It is Early Access, automations are not supported yet, the documented setup runs through Google Cloud and OAuth credentials, and nothing in it makes your hardware more capable. If you are already paying for Advanced because of the camera features, there is no extra charge to try it.

Budget buyer. Ignore, firmly. This is a subscription feature on a subscription tier. No device gets better and no device gets cheaper.

Does this change my picks?

No.

Google and Nest ratings. Cloud dependency, local control and Home Assistant quality all describe how a device behaves without the internet. A new cloud API does not touch that. Nothing in the catalog changes.
Zigbee vs Z-Wave vs Matter vs Thread. My reading there, that Google Home has one of the weakest local-first stories among the big platforms, stands, and this is more evidence for it rather than against.
Home Assistant with Google Home fallback. The advice to expose only the entities you are comfortable exposing was already there. It matters more now, and that page deserves a paragraph on Home MCP once Google documents the scope.
How to stop your smart home from phoning home. Unchanged. Event history leaving your house is the existing trade in a Google account, not a new one.

Sources

Every fact above comes from these sources, checked Oct 14, 2026. A launch brief is written before hands-on testing; the "what I verified" box says what is confirmed and what is not.

Google Home opens to AI agents: what Home MCP changes for a local house