Introduce dynamic discovery of commissionable Matter devices to guide users in setting them up #247

Problem statement

Today, adding a Matter device starts with the user looking for a dialog: Settings → Devices & services (or Connectivity) → Matter → Add device. The user must already know their device is Matter, know where the add action lives, and find it — before anything happens.

Yet a factory-new Matter device announces itself the moment it is powered on: it advertises over Bluetooth LE (and, once on a network, via mDNS) that it is in commissioning mode. Home Assistant — with Bluetooth proxies, a host adapter, or simply being on the same LAN — can see this. It does so already for many other integrations, surfacing them under "Discovered". For Matter, it doesn't.

This is the first place new users find out whether Home Assistant is approachable. Instead of the user finding the dialog, Home Assistant should notice the device and offer to add it. Discovery becomes the entry point; the setup code stays the proof of ownership.

Related community thinking: home-assistant/discussions#4796. This effort complements OpenHomeFoundation/goals#19, #177 and #237 and builds on the browser commissioning path (separate opportunity) for the actual commissioning step.

Community signals

No response

Scope & Boundaries

In scope

• Detection of commissionable Matter devices via BLE advertisements (proxies / host adapter) and mDNS _matterc._udp on the LAN
• Surfacing the discovery on the surfaces where users already are, converging on one confirmation step:
  • "Discovered" card under Settings → Devices & services (reusing the existing pattern)
  • Dashboard banner / card
  • Push notification via the Companion App (?)
  • Wall-panel toast for always-on shared screens (?)
• Confirmation with the setup code (or QR scan) — discovery never commissions without proof of ownership
• Handing over to the browser commissioning flow (or the Companion App where a phone is the only radio) and ending in the first-device wizard (First device setup wizard focusing on Matter devices #31)
• Honest handling of expired announcements: devices stay in commissioning mode only briefly — stale discoveries must say so and explain how to re-trigger pairing mode

Not in scope

• Commissioning transport itself (covered by browser / Companion App opportunities)
• Discovery of devices already commissioned into another fabric (multi-admin sharing is a different flow)
• Other protocols than Matter / Thread

Foreseen solution

• tbd

Risks & open questions

No response

Appetite

Medium - 1-2 cycles

Execution issues

No response

Decision log