diff --git a/soti/umsats_soti/parser/parser.py b/soti/umsats_soti/parser/parser.py
index 18d8f57..30b709e 100644
--- a/soti/umsats_soti/parser/parser.py
+++ b/soti/umsats_soti/parser/parser.py
@@ -95,11 +95,13 @@ def parse_send(args: str, default_sender: NodeID) -> Message:
     """
     parts = args.split()
 
+    if(len(parts) == 0):
+        raise ValueError("No arguments provided")
     try:
         cmd_id = CmdID(parse_int(parts[0]))
     except ValueError as e:
         raise ArgumentException(f"Invalid command ID '{parts[0]}'") from e
-
+        
     # Assign default values for the command options.
     priority: int = 255
     sender_id: NodeID = default_sender
diff --git a/soti/umsats_soti/screens/main_screen.py b/soti/umsats_soti/screens/main_screen.py
index 99f7bc2..e78a2d0 100644
--- a/soti/umsats_soti/screens/main_screen.py
+++ b/soti/umsats_soti/screens/main_screen.py
@@ -112,8 +112,10 @@ def _on_command_entered(self, text: str):
                     msg = parser.parse_send(args, self.sender_id)
                     self.device.write(msg)
                 except (ValueError, parser.ArgumentException) as e:
-                    self.console.print(str(e))
+                    self.console.print("Error: " + str(e))
                     return
+            case _:
+                self.console.print(f"Unknown command: {parts[0]}")
 
     def _on_message_received(self, msg: Message):
         """Called when a new message arrives."""