Matter

Every Matter device in your home is watched right out of the box, whether it talks over Thread or over Wi-Fi. This page explains what that means for each, what is still being built, and how you can help.

What Works Today

Each Matter device gets the full treatment automatically. Device Sentinel learns its reporting rhythm, calculates its freeze window, and watches it for freezes, unavailable states and unknown states. If it reports a battery or a signal, those are watched too, and it appears on your problem list and in your daily brief as every other device does.

When Matter loses touch with a device, Home Assistant marks it unavailable straight away, so Device Sentinel reports it without waiting out a freeze window. A device behind a Matter bridge is marked the same way when the bridge says it can no longer reach it.

If the Matter integration itself fails, it's caught as one integration outage: one row naming it, and the devices behind it are cleared of blame. When it comes back, that row counts your devices home as they rejoin, and the slow ones get a few minutes before any of them is reported on its own.

Matter Over Thread

Thread devices form their own low-power mesh, reaching Home Assistant through a Thread border router, such as a Home Assistant Connect ZBT-1, an Apple TV or HomePod, or a Google Nest hub.

• Battery-powered Thread devices sleep most of the time. They wake to report and go back to sleep, so their rhythm is slow and their freeze window is wide. Device Sentinel learns that rhythm for each device rather than applying one timeout to all of them.
• Mains-powered Thread devices usually act as routers, carrying traffic for the sleepy ones. When a router-capable plug or bulb goes offline, the battery devices that relied on it can go quiet too. If several Thread devices drop at once, look at the routers near them first.
• When the border router goes down, every Thread device behind it goes quiet together.

Matter Over Wi-Fi

Wi-Fi Matter devices talk over your ordinary Wi-Fi network, as your other Wi-Fi devices do.

• They depend on your Wi-Fi. When your network drops, they go unavailable with it. Set up WiFi outage watching, so the network going down is recorded as its own event.
• Their signal matters. A Wi-Fi Matter device at the edge of your coverage drops out more often than one near an access point, and one that keeps dropping out and coming back is shown as flapping.

What Is Not Built Yet

No Border Router or Server Sensor. There is no "Bridge: Matter" sensor. A failure of the Matter integration itself is still caught as an integration outage, as described above.

No Commissioning Recognition. Device Sentinel cannot see when you are adding or re-pairing a Matter device. When you add, replace or reset one by hand, turn on Maintenance Mode first, so your fix isn't learned as the device's normal rhythm.

Wi-Fi Outages. During a Wi-Fi outage, Matter devices on Wi-Fi may be reported on their own rather than counted in the outage.

No Last-Contact Time. Matter does not record when it last heard from a device, so there is no last-seen time to enable for Matter devices. Device Sentinel judges them on their learned rhythm alone.

None of these stop Device Sentinel from catching a Matter device that has died. They only change how much context you see beside it.

Help Build Matter Support

Turn on Matter under Extended Diagnostics and follow How to Submit Your Data there. The tests that help most on Matter: power off a Matter-over-Wi-Fi plug for 10 minutes, take the battery out of a Thread sensor until it reads unavailable or frozen, and unplug your Thread border router for 10 minutes. In the issue, say which border router you use, roughly how many Matter devices you have, and how many are on Thread and how many on Wi-Fi.