The window hides to the tray on close, so the natural next step for a shop assistant is to double-click the shortcut again. That started a second full copy of the app: a second tray icon, a second engine supervisor on the same SQLite WAL and the same port - the start-twice failure the agent package was built to prevent, on the one binary that never had the guard. Seen on a Windows install as a row of tray icons. Wails' SingleInstanceLock now hands the second launch to the first process, which brings its window to the front. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01KGcjxF1cNLcuwc3DAPcnfj
Behavision desktop
The store-facing app: a tray icon, a window, and the supervisor for the Python recognition engine.
Why one process, not three
The tray, the window and the supervisor all need the same state, and a user who quits the tray expects recognition to stop. Splitting them means two things can disagree about whether the engine is running.
It is deliberately not a Windows service. A service runs in session 0 and cannot draw a tray icon — that is Windows session isolation, not a library limitation. Spawning a child process also needs no elevation, while controlling a service does, so this design never triggers UAC at runtime.
Layout
main.go wails.Run, window options
app.go the methods bound to the frontend
tray.go fyne.io/systray — wails v2 has no tray of its own
icons.go tray icons generated at run time, not embedded
internal/local client for the engine on 127.0.0.1:8010
internal/cloud client for https://mcp.loyaly.ai
frontend/ React + Vite
The supervisor, durable spool, broker client and path resolution come from
../agent/pkg/* — the same tested code the headless agent runs, imported
rather than copied.
Build
cd frontend && npm install && npm run build # then, from this directory:
wails build -platform windows/amd64
wails build needs the Wails CLI:
go install github.com/wailsapp/wails/v2/cmd/wails@v2.9.2
Without it, go build still type-checks everything provided
frontend/dist exists — the embed directive requires it.
What the frontend talks to
Nothing is imported from generated bindings. src/bridge.js calls
window.go.main.App.* directly, so npm run build works without running
wails generate, and there is one place that handles "the engine is not
running yet" — the state every screen has to survive on a fresh install.