Send $/start notification to the serial client upon startup.

internal/msgpackrouter/router.go

@@ -43,9 +43,13 @@ func New() *Router {
 }
 
 func (r *Router) Accept(conn io.ReadWriteCloser) <-chan struct{} {
+	return r.AcceptAndSendNotification(conn, false)
+}
+
+func (r *Router) AcceptAndSendNotification(conn io.ReadWriteCloser, sendStartNotification bool) <-chan struct{} {
 	res := make(chan struct{})
 	go func() {
-		r.connectionLoop(conn)
+		r.connectionLoop(conn, sendStartNotification)
 		close(res)
 	}()
 	return res
@@ -66,7 +70,7 @@ func (r *Router) RegisterMethod(method string, handler RouterRequestHandler) err
 	return nil
 }
 
-func (r *Router) connectionLoop(conn io.ReadWriteCloser) {
+func (r *Router) connectionLoop(conn io.ReadWriteCloser, sendStartNotification bool) {
 	defer conn.Close()
 
 	var msgpackconn *msgpackrpc.Connection
@@ -158,6 +162,14 @@ func (r *Router) connectionLoop(conn io.ReadWriteCloser) {
 		},
 	)
 
+	if sendStartNotification {
+		// Send the start notification to the client
+		if err := msgpackconn.SendNotification("$/start", nil); err != nil {
+			slog.Error("Failed to send $/start notification", "err", err)
+			return
+		}
+	}
+
 	msgpackconn.Run()
 
 	// Unregister the methods when the connection is terminated

main.go

@@ -250,7 +250,7 @@ func startRouter(cfg Config) error {
 				wr := &MsgpackDebugStream{Name: cfg.SerialPortAddr, Upstream: serialPort}
 
 				// wait for the close command from RPC or for a failure of the serial port (routerExit)
-				routerExit := router.Accept(wr)
+				routerExit := router.AcceptAndSendNotification(wr, true)
 				select {
 				case <-routerExit:
 					slog.Info("Serial port failed connection")