diff --git a/xml_converter/generators/cpp_templates/multiflagvalue.cpp b/xml_converter/generators/cpp_templates/multiflagvalue.cpp
index 7f8593d4..5dd088e9 100644
--- a/xml_converter/generators/cpp_templates/multiflagvalue.cpp
+++ b/xml_converter/generators/cpp_templates/multiflagvalue.cpp
@@ -49,12 +49,13 @@ void xml_attribute_to_{{attribute_name}}(
 }
 
 string {{attribute_name}}_to_xml_attribute(const std::string& attribute_name, const {{class_name}}* value) {
-    string output = "";
+    vector<string> flag_values;
     {% for n, attribute_variable in enumerate(attribute_variables)%}
         if (value->{{attribute_variable.attribute_name}} == true) {
-            output = output + "{{attribute_variable.xml_fields[0]}}";
+            flag_values.push_back("{{attribute_variable.xml_fields[0]}}");
         }
     {% endfor %}
+    string output = join(flag_values, ",");
     return " " + attribute_name + "=\"" + output + "\"";
 }
 
diff --git a/xml_converter/intigration_tests/expected_outputs/xml_mount_filter_invalid/xml_file.xml b/xml_converter/intigration_tests/expected_outputs/xml_mount_filter_invalid/xml_file.xml
new file mode 100644
index 00000000..3276bdf2
--- /dev/null
+++ b/xml_converter/intigration_tests/expected_outputs/xml_mount_filter_invalid/xml_file.xml
@@ -0,0 +1,11 @@
+<OverlayData>
+<MarkerCategory  Name="mycategory">
+</MarkerCategory>
+
+<POIs>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="raptor,springer" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="raptor,springer" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+</POIs>
+</OverlayData>
diff --git a/xml_converter/intigration_tests/expected_outputs/xml_mount_filter_valid/xml_file.xml b/xml_converter/intigration_tests/expected_outputs/xml_mount_filter_valid/xml_file.xml
new file mode 100644
index 00000000..6b80f183
--- /dev/null
+++ b/xml_converter/intigration_tests/expected_outputs/xml_mount_filter_valid/xml_file.xml
@@ -0,0 +1,11 @@
+<OverlayData>
+<MarkerCategory  Name="mycategory">
+</MarkerCategory>
+
+<POIs>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="raptor" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="raptor,springer" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="raptor,springer" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+<POI  Type="mycategory" IconFile="texture.png" MapID="50" Mount="raptor,springer,skimmer,jackal,griffon,rollerbeetle,warclaw,skyscale,skiff,seigeturtle" XPos="169.809998" YPos="210.649994" ZPos="215.830002"/>
+</POIs>
+</OverlayData>
diff --git a/xml_converter/intigration_tests/inputs/xml_mount_filter_invalid/xml_file.xml b/xml_converter/intigration_tests/inputs/xml_mount_filter_invalid/xml_file.xml
new file mode 100644
index 00000000..3ee980aa
--- /dev/null
+++ b/xml_converter/intigration_tests/inputs/xml_mount_filter_invalid/xml_file.xml
@@ -0,0 +1,11 @@
+<OverlayData>
+<MarkerCategory  Name="mycategory">
+</MarkerCategory>
+
+<POIs>
+<POI Mount="" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+<POI Mount="NotAMount" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+<POI Mount="Raptor,Springer," Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+<POI Mount="Raptor,NotAMount,Springer" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+</POIs>
+</OverlayData>
diff --git a/xml_converter/intigration_tests/inputs/xml_mount_filter_valid/xml_file.xml b/xml_converter/intigration_tests/inputs/xml_mount_filter_valid/xml_file.xml
new file mode 100644
index 00000000..b3e44ac7
--- /dev/null
+++ b/xml_converter/intigration_tests/inputs/xml_mount_filter_valid/xml_file.xml
@@ -0,0 +1,11 @@
+<OverlayData>
+<MarkerCategory  Name="mycategory">
+</MarkerCategory>
+
+<POIs>
+<POI Mount="Raptor" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+<POI Mount="Raptor,Springer" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+<POI Mount="Raptor, Springer" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+<POI Mount="Raptor,Springer,Skimmer,Jackal,Griffon,RollerBeetle,Warclaw,Skyscale,Skiff,SeigeTurtle" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>
+</POIs>
+</OverlayData>
diff --git a/xml_converter/intigration_tests/testcases.py b/xml_converter/intigration_tests/testcases.py
index 4ab5b7b0..01c8e01f 100644
--- a/xml_converter/intigration_tests/testcases.py
+++ b/xml_converter/intigration_tests/testcases.py
@@ -33,4 +33,32 @@ class Testcase:
             "  |               ^^^"
         ]
     ),
+    Testcase(
+        name="mountfilter_valid",
+        xml_input_paths=["./inputs/xml_mount_filter_valid"],
+        expected_output_xml_path="./expected_outputs/xml_mount_filter_valid",
+    ),
+    Testcase(
+        name="mountfilter_invalid",
+        xml_input_paths=["./inputs/xml_mount_filter_invalid"],
+        expected_output_xml_path="./expected_outputs/xml_mount_filter_invalid",
+        expected_stdout=[
+            'Error: Invalid Filter for MountFilter. Found ',
+            './inputs/xml_mount_filter_invalid/xml_file.xml',
+            '6 |<POI Mount="" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>',
+            '  |            ',
+            'Error: Invalid Filter for MountFilter. Found NotAMount',
+            './inputs/xml_mount_filter_invalid/xml_file.xml',
+            '7 |<POI Mount="NotAMount" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>',
+            '  |            ^^^^^^^^^',
+            'Error: Invalid Filter for MountFilter. Found ',
+            './inputs/xml_mount_filter_invalid/xml_file.xml',
+            '8 |<POI Mount="Raptor,Springer," Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>',
+            '  |            ^^^^^^^^^^^^^^^^',
+            'Error: Invalid Filter for MountFilter. Found NotAMount',
+            './inputs/xml_mount_filter_invalid/xml_file.xml',
+            '9 |<POI Mount="Raptor,NotAMount,Springer" Type="mycategory" XPos="169.81" YPos="210.65" ZPos="215.83" MapID="50" IconFile="texture.png" Type="mycategory"/>',
+            '  |            ^^^^^^^^^^^^^^^^^^^^^^^^^',
+            ]
+    ),
 ]
diff --git a/xml_converter/src/attribute/festival_filter_gen.cpp b/xml_converter/src/attribute/festival_filter_gen.cpp
index 747ade9e..035e8a3b 100644
--- a/xml_converter/src/attribute/festival_filter_gen.cpp
+++ b/xml_converter/src/attribute/festival_filter_gen.cpp
@@ -64,28 +64,29 @@ void xml_attribute_to_festival_filter(
 }
 
 string festival_filter_to_xml_attribute(const std::string& attribute_name, const FestivalFilter* value) {
-    string output = "";
+    vector<string> flag_values;
     if (value->dragonbash == true) {
-        output = output + "dragonbash";
+        flag_values.push_back("dragonbash");
     }
     if (value->festival_of_the_four_winds == true) {
-        output = output + "festivalofthefourwinds";
+        flag_values.push_back("festivalofthefourwinds");
     }
     if (value->halloween == true) {
-        output = output + "halloween";
+        flag_values.push_back("halloween");
     }
     if (value->lunar_new_year == true) {
-        output = output + "lunarnewyear";
+        flag_values.push_back("lunarnewyear");
     }
     if (value->super_adventure_festival == true) {
-        output = output + "superadventurefestival";
+        flag_values.push_back("superadventurefestival");
     }
     if (value->wintersday == true) {
-        output = output + "wintersday";
+        flag_values.push_back("wintersday");
     }
     if (value->none == true) {
-        output = output + "none";
+        flag_values.push_back("none");
     }
+    string output = join(flag_values, ",");
     return " " + attribute_name + "=\"" + output + "\"";
 }
 
diff --git a/xml_converter/src/attribute/map_type_filter_gen.cpp b/xml_converter/src/attribute/map_type_filter_gen.cpp
index fee22ef1..9ef0273b 100644
--- a/xml_converter/src/attribute/map_type_filter_gen.cpp
+++ b/xml_converter/src/attribute/map_type_filter_gen.cpp
@@ -129,79 +129,80 @@ void xml_attribute_to_map_type_filter(
 }
 
 string map_type_filter_to_xml_attribute(const std::string& attribute_name, const MapTypeFilter* value) {
-    string output = "";
+    vector<string> flag_values;
     if (value->unknown_map == true) {
-        output = output + "unknown";
+        flag_values.push_back("unknown");
     }
     if (value->redirect_map == true) {
-        output = output + "redirect";
+        flag_values.push_back("redirect");
     }
     if (value->character_create_map == true) {
-        output = output + "charactercreate";
+        flag_values.push_back("charactercreate");
     }
     if (value->pvp_map == true) {
-        output = output + "pvp";
+        flag_values.push_back("pvp");
     }
     if (value->gvg_map == true) {
-        output = output + "gvg";
+        flag_values.push_back("gvg");
     }
     if (value->instance_map == true) {
-        output = output + "instance";
+        flag_values.push_back("instance");
     }
     if (value->public_map == true) {
-        output = output + "public";
+        flag_values.push_back("public");
     }
     if (value->tournament_map == true) {
-        output = output + "tournament";
+        flag_values.push_back("tournament");
     }
     if (value->tutorial_map == true) {
-        output = output + "tutorial";
+        flag_values.push_back("tutorial");
     }
     if (value->user_tournament_map == true) {
-        output = output + "usertournament";
+        flag_values.push_back("usertournament");
     }
     if (value->center_map == true) {
-        output = output + "center";
+        flag_values.push_back("center");
     }
     if (value->eternal_battlegrounds_map == true) {
-        output = output + "eternalbattlegrounds";
+        flag_values.push_back("eternalbattlegrounds");
     }
     if (value->bluehome_map == true) {
-        output = output + "bluehome";
+        flag_values.push_back("bluehome");
     }
     if (value->blue_borderlands_map == true) {
-        output = output + "blueborderlands";
+        flag_values.push_back("blueborderlands");
     }
     if (value->green_home_map == true) {
-        output = output + "greenhome";
+        flag_values.push_back("greenhome");
     }
     if (value->green_borderlands_map == true) {
-        output = output + "greenborderlands";
+        flag_values.push_back("greenborderlands");
     }
     if (value->red_home_map == true) {
-        output = output + "redhome";
+        flag_values.push_back("redhome");
     }
     if (value->red_borderlands_map == true) {
-        output = output + "redborderlands";
+        flag_values.push_back("redborderlands");
     }
     if (value->fortunes_vale_map == true) {
-        output = output + "fortunesvale";
+        flag_values.push_back("fortunesvale");
     }
     if (value->jump_puzzle_map == true) {
-        output = output + "jumppuzzle";
+        flag_values.push_back("jumppuzzle");
     }
     if (value->obsidian_sanctum_map == true) {
-        output = output + "obsidiansanctum";
+        flag_values.push_back("obsidiansanctum");
     }
     if (value->edge_of_the_mists_map == true) {
-        output = output + "edgeofthemists";
+        flag_values.push_back("edgeofthemists");
     }
     if (value->public_mini_map == true) {
-        output = output + "publicmini";
+        flag_values.push_back("publicmini");
     }
     if (value->wvw_lounge_map == true) {
-        output = output + "wvwlounge";
+        flag_values.push_back("wvwlounge");
     }
+    string output = join(flag_values, ",");
     return " " + attribute_name + "=\"" + output + "\"";
 }
 
diff --git a/xml_converter/src/attribute/mount_filter_gen.cpp b/xml_converter/src/attribute/mount_filter_gen.cpp
index 4a0e4a5d..bdd8930c 100644
--- a/xml_converter/src/attribute/mount_filter_gen.cpp
+++ b/xml_converter/src/attribute/mount_filter_gen.cpp
@@ -73,37 +73,38 @@ void xml_attribute_to_mount_filter(
 }
 
 string mount_filter_to_xml_attribute(const std::string& attribute_name, const MountFilter* value) {
-    string output = "";
+    vector<string> flag_values;
     if (value->raptor == true) {
-        output = output + "raptor";
+        flag_values.push_back("raptor");
     }
     if (value->springer == true) {
-        output = output + "springer";
+        flag_values.push_back("springer");
     }
     if (value->skimmer == true) {
-        output = output + "skimmer";
+        flag_values.push_back("skimmer");
     }
     if (value->jackal == true) {
-        output = output + "jackal";
+        flag_values.push_back("jackal");
     }
     if (value->griffon == true) {
-        output = output + "griffon";
+        flag_values.push_back("griffon");
     }
     if (value->roller_beetle == true) {
-        output = output + "rollerbeetle";
+        flag_values.push_back("rollerbeetle");
     }
     if (value->warclaw == true) {
-        output = output + "warclaw";
+        flag_values.push_back("warclaw");
     }
     if (value->skyscale == true) {
-        output = output + "skyscale";
+        flag_values.push_back("skyscale");
     }
     if (value->skiff == true) {
-        output = output + "skiff";
+        flag_values.push_back("skiff");
     }
     if (value->seige_turtle == true) {
-        output = output + "seigeturtle";
+        flag_values.push_back("seigeturtle");
     }
+    string output = join(flag_values, ",");
     return " " + attribute_name + "=\"" + output + "\"";
 }
 
diff --git a/xml_converter/src/attribute/profession_filter_gen.cpp b/xml_converter/src/attribute/profession_filter_gen.cpp
index 7eeb9ae2..039eaaf3 100644
--- a/xml_converter/src/attribute/profession_filter_gen.cpp
+++ b/xml_converter/src/attribute/profession_filter_gen.cpp
@@ -69,34 +69,35 @@ void xml_attribute_to_profession_filter(
 }
 
 string profession_filter_to_xml_attribute(const std::string& attribute_name, const ProfessionFilter* value) {
-    string output = "";
+    vector<string> flag_values;
     if (value->guardian == true) {
-        output = output + "guardian";
+        flag_values.push_back("guardian");
     }
     if (value->warrior == true) {
-        output = output + "warrior";
+        flag_values.push_back("warrior");
     }
     if (value->engineer == true) {
-        output = output + "engineer";
+        flag_values.push_back("engineer");
     }
     if (value->ranger == true) {
-        output = output + "ranger";
+        flag_values.push_back("ranger");
     }
     if (value->thief == true) {
-        output = output + "thief";
+        flag_values.push_back("thief");
     }
     if (value->elementalist == true) {
-        output = output + "elementalist";
+        flag_values.push_back("elementalist");
     }
     if (value->mesmer == true) {
-        output = output + "mesmer";
+        flag_values.push_back("mesmer");
     }
     if (value->necromancer == true) {
-        output = output + "necromancer";
+        flag_values.push_back("necromancer");
     }
     if (value->revenant == true) {
-        output = output + "revenant";
+        flag_values.push_back("revenant");
     }
+    string output = join(flag_values, ",");
     return " " + attribute_name + "=\"" + output + "\"";
 }
 
diff --git a/xml_converter/src/attribute/specialization_filter_gen.cpp b/xml_converter/src/attribute/specialization_filter_gen.cpp
index a6435619..4d7e2c46 100644
--- a/xml_converter/src/attribute/specialization_filter_gen.cpp
+++ b/xml_converter/src/attribute/specialization_filter_gen.cpp
@@ -402,223 +402,224 @@ void xml_attribute_to_specialization_filter(
 }
 
 string specialization_filter_to_xml_attribute(const std::string& attribute_name, const SpecializationFilter* value) {
-    string output = "";
+    vector<string> flag_values;
     if (value->elementalist_tempest == true) {
-        output = output + "48";
+        flag_values.push_back("48");
     }
     if (value->engineer_scrapper == true) {
-        output = output + "43";
+        flag_values.push_back("43");
     }
     if (value->guardian_dragonhunter == true) {
-        output = output + "27";
+        flag_values.push_back("27");
     }
     if (value->mesmer_chronomancer == true) {
-        output = output + "40";
+        flag_values.push_back("40");
     }
     if (value->necromancer_reaper == true) {
-        output = output + "34";
+        flag_values.push_back("34");
     }
     if (value->ranger_druid == true) {
-        output = output + "5";
+        flag_values.push_back("5");
     }
     if (value->revenant_herald == true) {
-        output = output + "52";
+        flag_values.push_back("52");
     }
     if (value->thief_daredevil == true) {
-        output = output + "7";
+        flag_values.push_back("7");
     }
     if (value->warrior_berserker == true) {
-        output = output + "18";
+        flag_values.push_back("18");
     }
     if (value->elementalist_weaver == true) {
-        output = output + "56";
+        flag_values.push_back("56");
     }
     if (value->engineer_holosmith == true) {
-        output = output + "57";
+        flag_values.push_back("57");
     }
     if (value->guardian_firebrand == true) {
-        output = output + "62";
+        flag_values.push_back("62");
     }
     if (value->mesmer_mirage == true) {
-        output = output + "59";
+        flag_values.push_back("59");
     }
     if (value->necromancer_scourge == true) {
-        output = output + "60";
+        flag_values.push_back("60");
     }
     if (value->ranger_soulbeast == true) {
-        output = output + "55";
+        flag_values.push_back("55");
     }
     if (value->revenant_renegade == true) {
-        output = output + "63";
+        flag_values.push_back("63");
     }
     if (value->thief_deadeye == true) {
-        output = output + "58";
+        flag_values.push_back("58");
     }
     if (value->warrior_spellbreaker == true) {
-        output = output + "61";
+        flag_values.push_back("61");
     }
     if (value->elementalist_catalyst == true) {
-        output = output + "67";
+        flag_values.push_back("67");
     }
     if (value->engineer_mechanist == true) {
-        output = output + "70";
+        flag_values.push_back("70");
     }
     if (value->guardian_willbender == true) {
-        output = output + "65";
+        flag_values.push_back("65");
     }
     if (value->mesmer_virtuoso == true) {
-        output = output + "66";
+        flag_values.push_back("66");
     }
     if (value->necromancer_harbinger == true) {
-        output = output + "64";
+        flag_values.push_back("64");
     }
     if (value->ranger_untamed == true) {
-        output = output + "72";
+        flag_values.push_back("72");
     }
     if (value->revenant_vindicator == true) {
-        output = output + "69";
+        flag_values.push_back("69");
     }
     if (value->thief_specter == true) {
-        output = output + "71";
+        flag_values.push_back("71");
     }
     if (value->warrior_bladesworn == true) {
-        output = output + "68";
+        flag_values.push_back("68");
     }
     if (value->elementalist_air == true) {
-        output = output + "41";
+        flag_values.push_back("41");
     }
     if (value->elementalist_arcane == true) {
-        output = output + "37";
+        flag_values.push_back("37");
     }
     if (value->elementalist_earth == true) {
-        output = output + "26";
+        flag_values.push_back("26");
     }
     if (value->elementalist_fire == true) {
-        output = output + "31";
+        flag_values.push_back("31");
     }
     if (value->elementalist_water == true) {
-        output = output + "17";
+        flag_values.push_back("17");
     }
     if (value->engineer_alchemy == true) {
-        output = output + "29";
+        flag_values.push_back("29");
     }
     if (value->engineer_explosives == true) {
-        output = output + "6";
+        flag_values.push_back("6");
     }
     if (value->engineer_firearms == true) {
-        output = output + "38";
+        flag_values.push_back("38");
     }
     if (value->engineer_inventions == true) {
-        output = output + "47";
+        flag_values.push_back("47");
     }
     if (value->engineer_tools == true) {
-        output = output + "21";
+        flag_values.push_back("21");
     }
     if (value->guardian_honor == true) {
-        output = output + "49";
+        flag_values.push_back("49");
     }
     if (value->guardian_radiance == true) {
-        output = output + "16";
+        flag_values.push_back("16");
     }
     if (value->guardian_valor == true) {
-        output = output + "13";
+        flag_values.push_back("13");
     }
     if (value->guardian_virtues == true) {
-        output = output + "46";
+        flag_values.push_back("46");
     }
     if (value->guardian_zeal == true) {
-        output = output + "42";
+        flag_values.push_back("42");
     }
     if (value->mesmer_chaos == true) {
-        output = output + "45";
+        flag_values.push_back("45");
     }
     if (value->mesmer_domination == true) {
-        output = output + "10";
+        flag_values.push_back("10");
     }
     if (value->mesmer_dueling == true) {
-        output = output + "1";
+        flag_values.push_back("1");
     }
     if (value->mesmer_illusions == true) {
-        output = output + "24";
+        flag_values.push_back("24");
     }
     if (value->mesmer_inspiration == true) {
-        output = output + "23";
+        flag_values.push_back("23");
     }
     if (value->necromancer_blood_magic == true) {
-        output = output + "19";
+        flag_values.push_back("19");
     }
     if (value->necromancer_curses == true) {
-        output = output + "39";
+        flag_values.push_back("39");
     }
     if (value->necromancer_death_magic == true) {
-        output = output + "2";
+        flag_values.push_back("2");
     }
     if (value->necromancer_soul_reaping == true) {
-        output = output + "50";
+        flag_values.push_back("50");
     }
     if (value->necromancer_spite == true) {
-        output = output + "53";
+        flag_values.push_back("53");
     }
     if (value->ranger_beastmastery == true) {
-        output = output + "32";
+        flag_values.push_back("32");
     }
     if (value->ranger_marksmanship == true) {
-        output = output + "8";
+        flag_values.push_back("8");
     }
     if (value->ranger_nature_magic == true) {
-        output = output + "25";
+        flag_values.push_back("25");
     }
     if (value->ranger_skirmishing == true) {
-        output = output + "30";
+        flag_values.push_back("30");
     }
     if (value->ranger_wilderness_survival == true) {
-        output = output + "33";
+        flag_values.push_back("33");
     }
     if (value->revenant_corruption == true) {
-        output = output + "14";
+        flag_values.push_back("14");
     }
     if (value->revenant_devastation == true) {
-        output = output + "15";
+        flag_values.push_back("15");
     }
     if (value->revenant_invocation == true) {
-        output = output + "3";
+        flag_values.push_back("3");
     }
     if (value->revenant_retribution == true) {
-        output = output + "9";
+        flag_values.push_back("9");
     }
     if (value->revenant_salvation == true) {
-        output = output + "12";
+        flag_values.push_back("12");
     }
     if (value->thief_acrobatics == true) {
-        output = output + "54";
+        flag_values.push_back("54");
     }
     if (value->thief_critical_strikes == true) {
-        output = output + "35";
+        flag_values.push_back("35");
     }
     if (value->thief_deadly_arts == true) {
-        output = output + "28";
+        flag_values.push_back("28");
     }
     if (value->thief_shadow_arts == true) {
-        output = output + "20";
+        flag_values.push_back("20");
     }
     if (value->thief_trickery == true) {
-        output = output + "44";
+        flag_values.push_back("44");
     }
     if (value->warrior_arms == true) {
-        output = output + "36";
+        flag_values.push_back("36");
     }
     if (value->warrior_defense == true) {
-        output = output + "22";
+        flag_values.push_back("22");
     }
     if (value->warrior_discipline == true) {
-        output = output + "51";
+        flag_values.push_back("51");
     }
     if (value->warrior_strength == true) {
-        output = output + "4";
+        flag_values.push_back("4");
     }
     if (value->warrior_tactics == true) {
-        output = output + "11";
+        flag_values.push_back("11");
     }
+    string output = join(flag_values, ",");
     return " " + attribute_name + "=\"" + output + "\"";
 }
 
diff --git a/xml_converter/src/attribute/species_filter_gen.cpp b/xml_converter/src/attribute/species_filter_gen.cpp
index af68e1f2..42151c76 100644
--- a/xml_converter/src/attribute/species_filter_gen.cpp
+++ b/xml_converter/src/attribute/species_filter_gen.cpp
@@ -53,22 +53,23 @@ void xml_attribute_to_species_filter(
 }
 
 string species_filter_to_xml_attribute(const std::string& attribute_name, const SpeciesFilter* value) {
-    string output = "";
+    vector<string> flag_values;
     if (value->asura == true) {
-        output = output + "asura";
+        flag_values.push_back("asura");
     }
     if (value->charr == true) {
-        output = output + "charr";
+        flag_values.push_back("charr");
     }
     if (value->human == true) {
-        output = output + "human";
+        flag_values.push_back("human");
     }
     if (value->norn == true) {
-        output = output + "norn";
+        flag_values.push_back("norn");
     }
     if (value->sylvari == true) {
-        output = output + "sylvari";
+        flag_values.push_back("sylvari");
     }
+    string output = join(flag_values, ",");
     return " " + attribute_name + "=\"" + output + "\"";
 }