InputScout

inputscout is an experimental Linux command-line tool for inspecting input devices. It communicates with supported receiver and wired configuration interfaces directly through HID reports and does not modify onboard settings.

The project is at an early stage. It currently provides device discovery, battery and wired keyboard telemetry, plus a native desktop tray indicator.

Roadmap · Desktop integration · Brand assets

Current support

Device	2.4 GHz detection	Wired telemetry	Battery	Writes
Keychron M5 8K	Yes	Not yet	Yes over receiver	No
Keychron K8 HE	Yes	Firmware, mode, features, and active HE profile	Not exposed over USB or receiver	No

The K8 HE firmware tracks its battery internally, but stock firmware v1.1.1 does not expose a percentage through its public wired raw-HID commands or the known 2.4 GHz receiver protocol. The remaining stock-firmware path to test is BlueZ's standard Battery1 interface in Bluetooth mode. See the wired protocol notes for evidence and scope.

Build

Building requires Go, GCC, and the libudev development headers.

make test
make build

The resulting binaries are written to bin/inputscout and bin/inputscout-tray.

Desktop tray

Install the CLI and tray process for the current user:

make install-user

This installs and starts inputscout-tray as a systemd user service. The tray icon follows the lowest available device battery, its tooltip lists all supported devices, and clicking it shows the current state as a desktop notification. Devices at 20% and 10% trigger low and critical notifications.

The tray refreshes once per minute. It uses the standard StatusNotifierItem protocol and does not require root access. See desktop battery integration for why receiver devices cannot currently be registered with UPower directly. The device permission rule from the next section still needs to be installed once on a new machine.

Useful service commands:

systemctl --user status inputscout-tray
systemctl --user restart inputscout-tray
journalctl --user -u inputscout-tray

Device permissions

Install the included udev rule once, then reconnect the receivers if the current desktop session does not receive access immediately:

make install-udev

The rules grant the active local session access only to the configuration interfaces of the currently supported receivers and K8 HE wired interface 01. They do not make normal keyboard input or all HID devices globally writable.

Usage

bin/inputscout status
bin/inputscout status --json
bin/inputscout list

Example:

Keychron K8 HE
  Connection: USB
  Device:     3434:0e80
  Connected:  yes
  Device mode: 2.4 GHz
  USB power:  connected
  Firmware:   v1.1.1
  Build:      2025-06-17 10:42:45
  Protocol:   2 (instruction set 2)
  OS mode:    Windows (layer 2)
  Features:   default layer, Bluetooth, 2.4 GHz, analog matrix, Keychron RGB
  HE profile: 1/3 (regular, 2.0 mm)
  Battery:    unavailable over this connection

Keychron M5 8K
  Connection: 2.4 GHz
  Receiver:   3434:d028
  Device:     3434:d048
  Connected:  yes
  Battery:    17%
  Charging:   no

Safety

The implemented commands only send receiver identity and read-only status queries that are also implemented by Keychron firmware and Launcher. InputScout does not capture key events or read profile names. Device configuration writes and firmware updates are intentionally out of scope for this first version.

Project independence

InputScout is an independent community project. It is not affiliated with or endorsed by Keychron. Product and company names are used only to identify compatible hardware.

Roadmap

The planned path includes a replayable driver architecture, diagnostics, read-only mouse configuration, safe reversible writes, K8 HE battery research, a D-Bus service, desktop clients, native packages, and a contributor-facing driver model. See the complete project roadmap.