Persistent device connections

Use deviceConnectionOpen, then deviceConnectionExchange, deviceConnectionRead and deviceConnectionClose. deviceConnectionsList pages lifecycle metadata. These shared commands work through HTTP, WebSocket, MCP, HTML and Lua. Every transfer counts as mutating for token and assistant access control.

Connections retain hardware across commands. The default lifetime is five minutes, configurable with maximumDurationMilliseconds from one second to one hour. At most eight connections can be active. A transfer uses timeoutMilliseconds (default 30000, maximum 120000), serializes access and closes on timeout. Reads and writes are bounded to 65536 bytes. Closing, expiry or process death releases hardware; retrying an interrupted write can duplicate peer effects. Completed peer effects are not undone.

Bluetooth

kind: rfcomm requires a paired device address and serviceUuid; secure defaults true. Exchange writes optional base64 bytes and reads up to readBytes. Returned chunks do not promise a complete message. Handle framing in the client.

kind: gatt requires an address. Exchange actions are discover, read, write, subscribe, unsubscribe and notifications. Use service/characteristic UUIDs and instance IDs when discovery reports duplicates. Notifications have bounded replay cursors and report loss. Bluetooth access and enabled hardware remain necessary.

The optional Vehicle console HTML template uses retained RFCOMM to query an owner-selected ELM327-compatible adapter. It reads RPM, coolant temperature and adapter voltage. It handles command framing and displays observation time. It never clears codes or sends vehicle actuation commands. Add it from the HTML template picker; it is not added to the starter home automatically.

USB and NFC

kind: usb requires an attached deviceId, optional interfaceIndex and owner access. Missing access returns a targeted usbRequestAccess recovery. Exchanges support control, bulk and interrupt. Control requires requestType/request/value/index. Bulk and interrupt identify an endpoint on the claimed interface. Supply readBytes for input or dataBase64 for output.

kind: nfc requires a foreground unlocked Dikciz activity and a physically presented tag. Choose technology, default IsoDep. Supported technologies include NfcA/B/F/V, Ndef and supported Mifare technologies. Exchange supports raw transceive, readNdef and writeNdef. Shared NFC ownership prevents simultaneous one-shot and retained readers. Tag removal is an explicit I/O failure. This does not implement payment decoding or card emulation.

A connected-device foreground notification exposes Stop all. Actual profiles, USB endpoints and tag technologies depend on physical hardware. An emulator does not establish real peripheral compatibility.

Vehicle document

This rendered WebView uses a deterministic mocked ELM adapter response with fragmented reads. It verifies framing, PID conversion, saved state and presentation. It is not a photograph of a connected car or proof of physical adapter compatibility.