diff --git a/tools/message_parser.cpp b/tools/message_parser.cpp
index f633fd3..a0bf15d 100644
--- a/tools/message_parser.cpp
+++ b/tools/message_parser.cpp
@@ -27,14 +27,14 @@ json command_parser(json command)
     json j;
     try
     {
-        std::string type = command["type"];
+        std::string type = command.at("type");
         Command cmd = magic_enum::enum_cast<Command>(type).value_or(Command::end);
         switch (cmd)
         {
             case Command::get_UI_element:
-                spdlog::info("Command {}: {}", type, std::string(command["id"]));
+                spdlog::info("Command {}: {}", type, std::string(command.at("id")));
                 j["response"]["type"] = type;
-                j["response"]["UI_item"] = g_simulators->invoke_active_simulator()->get_UI_item(command["id"])->to_json();
+                j["response"]["UI_item"] = g_simulators->invoke_active_simulator()->get_UI_item(command.at("id"))->to_json();
                 break;
             case Command::get_UI_elements:
                 spdlog::info("Command {}", type);
@@ -42,8 +42,8 @@ json command_parser(json command)
                 j["response"]["UI_items"] = g_simulators->invoke_active_simulator()->get_UI_items()["UI_items"];
                 break;
             case Command::switch_simulator:
-                spdlog::info("Command {} to {}", type, std::string(command["name"]));
-                g_simulators->switch_simulator(command["name"]);
+                spdlog::info("Command {} to {}", type, std::string(command.at("name")));
+                g_simulators->switch_simulator(command.at("name"));
                 j["response"]["type"] = type;
                 break;
             case Command::get_active_simulator_name:
@@ -64,7 +64,7 @@ json command_parser(json command)
     {
         spdlog::error(e.what());
     }
-    
+
     return j;
 }
 
@@ -72,7 +72,7 @@ void event_handler(json event)
 {
     try
     {
-        std::string type = event["type"];
+        std::string type = event.at("type");
         Event e = magic_enum::enum_cast<Event>(type).value_or(Event::end);
         if (g_simulators->invoke_active_simulator() == nullptr)
         {
@@ -84,26 +84,26 @@ void event_handler(json event)
         {
             case Event::clicked:
             {
-                spdlog::debug("Event {}: {}", type, std::string(event["id"]));
-                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event["id"]))->click();
+                spdlog::debug("Event {}: {}", type, std::string(event.at("id")));
+                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event.at("id")))->click();
                 break;
             }
             case Event::value_changed:
             {
-                spdlog::debug("Event {}: {} {}", type, std::string(event["id"]), (double)(event["value"]));
-                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event["id"]))->set_value((double)event["value"]);
+                spdlog::debug("Event {}: {} {}", type, std::string(event.at("id")), (double)(event["value"]));
+                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event.at("id")))->set_value((double)event.at("value"));
                 break;
             }
             case Event::text_changed:
             {
-                spdlog::debug("Event {}: {} {}", type, std::string(event["id"]), std::string(event["text"]));
-                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event["id"]))->set_text(std::string(event["text"]));
+                spdlog::debug("Event {}: {} {}", type, std::string(event.at("id")), std::string(event.at("text")));
+                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event.at("id")))->set_text(std::string(event.at("text")));
                 break;
             }
             case Event::selected:
             {
-                spdlog::debug("Event {}: {} {}", type, std::string(event["id"]), std::string(event["selected"]));
-                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event["id"]))->set_selected(std::string(event["selected"]));
+                spdlog::debug("Event {}: {} {}", type, std::string(event.at("id")), std::string(event.at("selected")));
+                g_simulators->invoke_active_simulator()->get_UI_item(std::string(event.at("id")))->set_selected(std::string(event.at("selected")));
                 break;
             }
             default: