Google Home opens its event history to any MCP agent for $20 a month

Taylor Lehman, group product manager at Google Home & Nest, said Home MCP "allows any AI agents that support MCP, including Google Antigravity, Claude, Hermes or Open Claw, to securely work with all of the devices and event history in your Google Home ecosystem" ^[2]. In the same blog post Lehman said that depending on the agent, "connecting it to Home MCP can result in unexpected or even undesired behavior", and recommended reviewing Google's developer policies and terms of service ^[8]. The second sentence is the one a support team will be quoting back to users.

Google is not moving its own front end out of the way. Gemini for Home stays the interface in the Home app and on Nest speakers after the demise of Google Assistant, and MCP adds another layer of control next to it ^[9]. The Verge wrote that the bigger change is not the lights going on from a Claude window but the user's agent of choice having access to the underlying data and control layer of the home ^[13].

For a team shipping a device or an integration on Google Home, the caller has changed. The account owner picks the agent, so device state and stored events can be read by a client the device maker never evaluated ^[1].

The money is small and easy to sign off. The monthly plan comes to $240 over twelve months, $40 more than paying annually ^[11]. The stiffer filter is the developer console: the people who will create a Google Cloud project to wire Claude into their house are the people already writing their own automations ^[6].

Here is a way to sort your own device list before you decide what to expose. Group everything by what a wrong call costs and whether the household can see and undo it. The first group is reads that cannot be taken back, such as camera history and the record of how long the lights were left on ^[4]. The second is writes a user reverses in a second: lights, scenes, a generated dashboard ^[4]. In the third sit writes that arrive with a bill or a safety consequence, and The Verge's list of those is smart locks, thermostats, and infrastructure like HVAC systems and appliances ^[14].

The closest thing to evidence about how people behave with an agent inside a home is Home Assistant's own MCP integration. The Verge tested it last year with Claude, and it handled troubleshooting, creating automations, designing a dashboard and advanced configuration in natural language ^[10]. The report does not include any figure for how many people have turned Home MCP on ^[12].