diff --git a/_locales/en/messages.json b/_locales/en/messages.json
index 4dc8f7e6..226ccf8d 100644
--- a/_locales/en/messages.json
+++ b/_locales/en/messages.json
@@ -850,5 +850,17 @@
   "thunderai_warning_title": {
     "message": "ThunderAI Warning",
     "description": ""
+  },
+  "prefs_OptionText_add_tags_first_uppercase": {
+    "message": "First letter uppercase",
+    "description": ""
+  },
+  "prefs_OptionText_add_tags_first_uppercase_Info": {
+    "message": "If checked, the tags label will be set to lowercase letters with only the first letter uppercase.",
+    "description": ""
+  },
+  "AddTags_prompt_prefs_title": {
+    "message": "Add Tags Options",
+    "description": ""
   }
 }
\ No newline at end of file
diff --git a/js/mzta-menus.js b/js/mzta-menus.js
index 908baec0..38fa4de7 100644
--- a/js/mzta-menus.js
+++ b/js/mzta-menus.js
@@ -218,7 +218,7 @@ export class mzta_Menus {
                         this.logger.log("fullPrompt: " + fullPrompt);
                         // TODO: use the current API, abort if using chatgpt web
                         // COMMENTED TO DO TESTS
-                        mail_tags = "recipients, test, home, work, car, light";
+                        mail_tags = "recipients, test, home, work, CAR, light";
                         // let cmd_addTags = new mzta_specialCommand_AddTags(fullPrompt,prefs_at.connection_type,true);
                         // await cmd_addTags.initWorker();
                         // try{
diff --git a/js/mzta-utils.js b/js/mzta-utils.js
index 4ff9bee6..27ab29eb 100644
--- a/js/mzta-utils.js
+++ b/js/mzta-utils.js
@@ -199,11 +199,13 @@ export async function getTagsList(){
 }
 
 export async function createTag(tag) {
+  let prefs_tag = await browser.storage.sync.get({add_tags_first_uppercase: true});
+  if(prefs_tag.add_tags_first_uppercase) tag = tag.toLowerCase().charAt(0).toUpperCase() + tag.toLowerCase().slice(1);
   try {
     if(await isThunderbird128OrGreater()) {
-      return browser.messages.tags.create('ta-'+tag, tag, generateHexColorForTag());
+      return browser.messages.tags.create('ta-'+tag.toLowerCase(), tag, generateHexColorForTag());
     }else{
-      return browser.messages.createTag('ta-'+tag, tag, generateHexColorForTag());
+      return browser.messages.createTag('ta-'+tag.toLowerCase(), tag, generateHexColorForTag());
     }
   } catch (error) {
     console.error('[ThunderAI] Error creating tag:', error);
@@ -212,7 +214,7 @@ export async function createTag(tag) {
 
 export async function assignTagToMessage(messageId, tag) {
   try {
-    return browser.messages.update(messageId, {tags: ["ta-"+tag]});
+    return browser.messages.update(messageId, {tags: ["ta-"+tag.toLowerCase()]});
   } catch (error) {
     console.error('[ThunderAI] Error assigning tag [messageId: ', messageId, ' - tag: ', tag, ']:', error);
   }
diff --git a/pages/addtags/mzta-add-tags.html b/pages/addtags/mzta-add-tags.html
index bf680236..d0323bd8 100644
--- a/pages/addtags/mzta-add-tags.html
+++ b/pages/addtags/mzta-add-tags.html
@@ -11,7 +11,7 @@
         <h1 class="page_title">__MSG_AddTags_PageTitle__</h1>
         <p>__MSG_AddTags_info_default__</p>
     </div>
-    <div class="addtags_table_title">__MSG_AddTags_prompt_text_title__</div>
+    <div class="addtags_table_title">__MSG_AddTags_prompt_prefs_title__</div>
     <table id="miczPrefs">
           <tr class="add_tags_tr">
             <td><span>__MSG_prefs_OptionText_add_tags_maxnum__</span></td>
@@ -31,6 +31,15 @@
               </label>
             </td>
           </tr>
+          <tr class="add_tags_tr">
+            <td><span>__MSG_prefs_OptionText_add_tags_first_uppercase__</span></td>
+            <td>
+              <label>
+                <input type="checkbox" id="add_tags_first_uppercase" name="add_tags_first_uppercase" class="option-input" />
+                __MSG_prefs_OptionText_add_tags_first_uppercase_Info__
+              </label>
+            </td>
+          </tr>
     </table>
     <div id="addtags_prompt_container">
         __MSG_AddTags_prompt_text_title__<span id="addtags_prompt_unsaved" class="unsaved hidden"> __MSG_customPrompts_unsaved_changes__</span>