diff --git a/grbl_machine.cpp b/grbl_machine.cpp
index 36cc674..4c39677 100644
--- a/grbl_machine.cpp
+++ b/grbl_machine.cpp
@@ -155,6 +155,85 @@ std::string grbl::alarm_to_string(int alarm) {
     }
 }
 
+std::string grbl::error_to_string(size_t error) {
+    switch (error) {
+        case 1:
+            return "G-code words consist of a letter and a value. Letter was not found.";
+        case 2:
+            return "Missing the expected G-code word value or numeric value format is not valid.";
+        case 3:
+            return "Grbl '$' system command was not recognized or supported.";
+        case 4:
+            return "Negative value received for an expected positive value.";
+        case 5:
+            return "Homing cycle failure. Homing is not enabled via settings.";
+        case 6:
+            return "Minimum step pulse time must be greater than 3usec.";
+        case 7:
+            return "An EEPROM read failed. Auto-restoring affected EEPROM to default values.";
+        case 8:
+            return "Grbl '$' command cannot be used unless Grbl is IDLE. Ensures smooth operation during a job.";
+        case 9:
+            return "G-code commands are locked out during alarm or jog state.";
+        case 10:
+            return "Soft limits cannot be enabled without homing also enabled.";
+        case 11:
+            return "Max characters per line exceeded. Received command line was not executed.";
+        case 12:
+            return "Grbl '$' setting value cause the step rate to exceed the maximum supported.";
+        case 13:
+            return "Safety door detected as opened and door state initiated.";
+        case 14:
+            return "Build info or startup line exceeded EEPROM line length limit. Line not stored.";
+        case 15:
+            return "Jog target exceeds machine travel. Jog command has been ignored.";
+        case 16:
+            return "Jog command has no '=' or contains prohibited g-code.";
+        case 17:
+            return "Laser mode requires PWM output.";
+        case 20:
+            return "Unsupported or invalid g-code command found in block.";
+        case 21:
+            return "More than one g-code command from same modal group found in block.";
+        case 22:
+            return "Feed rate has not yet been set or is undefined.";
+        case 23:
+            return "G-code command in block requires an integer value.";
+        case 24:
+            return "More than one g-code command that requires axis words found in block.";
+        case 25:
+            return "Repeated g-code word found in block.";
+        case 26:
+            return "No axis words found in block for g-code command or current modal state which requires them.";
+        case 27:
+            return "Line number value is invalid.";
+        case 28:
+            return "G-code command is missing a required value word.";
+        case 29:
+            return "G59.x work coordinate systems are not supported.";
+        case 30:
+            return "G53 only allowed with G0 and G1 motion modes.";
+        case 31:
+            return "Axis words found in block when no command or current modal state uses them.";
+        case 32:
+            return "G2 and G3 arcs require at least one in-plane axis word.";
+        case 33:
+            return "Motion command target is invalid.";
+        case 34:
+            return "Arc radius value is invalid.";
+        case 35:
+            return "G2 and G3 arcs require at least one in-plane offset word.";
+        case 36:
+            return "Unused value words found in block.";
+        case 37:
+            return "G43.1 dynamic tool length offset is not assigned to configured tool length axis.";
+        case 38:
+            return "Tool number greater than max supported value.";
+        default:
+            return "unknown error";
+    }
+}
+
 void grbl::machine::on_line_received(std::string line, grbl::transport *transport) {
     if (line.at(0) != '<')
         std::cout << ">> " << line << std::endl;
@@ -275,8 +354,8 @@ void grbl::machine::cancel_jog() const {
     pipe->send_single_char_command(0x85);
 }
 
-void grbl::machine::set_listener(grbl::machine_listener *listener) {
-    machine::listener = listener;
+void grbl::machine::set_listener(grbl::machine_listener *l) {
+    listener = l;
 }
 
 void grbl::machine::request_unlock() {
diff --git a/grbl_machine.h b/grbl_machine.h
index 9480e72..d7bf766 100644
--- a/grbl_machine.h
+++ b/grbl_machine.h
@@ -22,6 +22,7 @@ enum class machine_status {
 machine_status status_from_string(const std::string& status);
 std::string status_to_string(const machine_status& status);
 std::string alarm_to_string(int alarm);
+std::string error_to_string(size_t error);
 
 struct realtime_status_report {
     machine_status status;
@@ -104,8 +105,8 @@ struct machine_listener {
     virtual void on_banner(std::string line) = 0;
     virtual void on_message(std::string message) = 0;
     virtual void on_alarm(int alarm) = 0;
-    virtual void on_run_completed(bool success, size_t failed_index, int error) = 0;
-    virtual void on_check_completed(bool success, size_t failed_index, int error) = 0;
+    virtual void on_run_completed(bool success, size_t failed_index, size_t error) = 0;
+    virtual void on_check_completed(bool success, size_t failed_index, size_t error) = 0;
 };
 
 struct machine : public transport_callbacks {
@@ -119,7 +120,7 @@ struct machine : public transport_callbacks {
     void request_jog(jog_state jog) const;
     void cancel_jog() const;
 
-    realtime_status_report get_status() const { return last_report; };
+    [[nodiscard]] realtime_status_report get_status() const { return last_report; };
 
     void request_unlock();
     void request_home();
diff --git a/main.cpp b/main.cpp
index e354b65..3356985 100644
--- a/main.cpp
+++ b/main.cpp
@@ -360,7 +360,7 @@ public:
         last_alarm = alarm;
     }
 
-    void on_check_completed(bool success, size_t failed_index, int error) override {
+    void on_check_completed(bool success, size_t failed_index, size_t error) override {
         btnCheckProgram->set_background_color(success ? colGreen : colRed);
         if (success) {
             btnRunProgram->set_enabled(true);
@@ -369,19 +369,21 @@ public:
             btnRunProgram->set_enabled(false);
             std::stringstream ss;
             auto i = pgm.instruction_at(failed_index);
-            ss << "Program check failed at line " << i.line << " (" << i.command << "). Error: " << error;
+            ss << "Program check failed at line " << i.line << " (" << i.command << "). Error: " << error << ", "
+               << grbl::error_to_string(error);
             new MessageDialog(this, MessageDialog::Type::Warning, "Check result", ss.str());
         }
     }
 
-    void on_run_completed(bool success, size_t failed_index, int error) override {
+    void on_run_completed(bool success, size_t failed_index, size_t error) override {
         btnRunProgram->set_background_color(success ? colGreen : colRed);
         if (success) {
             new MessageDialog(this, MessageDialog::Type::Information, "Run result", "Program executed successfully");
         } else {
             std::stringstream ss;
             auto i = pgm.instruction_at(failed_index);
-            ss << "Program execution failed at line " << i.line << " (" << i.command << "). Error: " << error;
+            ss << "Program execution failed at line " << i.line << " (" << i.command << "). Error: " << error << ", "
+               << grbl::error_to_string(error);
             new MessageDialog(this, MessageDialog::Type::Warning, "Run result", ss.str());
         }
     }