diff --git a/web/src/app/wizard/page.tsx b/web/src/app/wizard/page.tsx
index c30340eaa..c40c209a6 100644
--- a/web/src/app/wizard/page.tsx
+++ b/web/src/app/wizard/page.tsx
@@ -1201,11 +1201,24 @@ function WizardModelScan({
     });
   };
 
+  const getExistingModelNames = async (): Promise<Set<string>> => {
+    if (!providerUuid) return new Set();
+    try {
+      const resp = await httpClient.getProviderLLMModels(providerUuid);
+      return new Set((resp.models ?? []).map((m: { name: string }) => m.name));
+    } catch {
+      return new Set();
+    }
+  };
+
   const handleAddSelected = async () => {
     if (!providerUuid || selectedModels.size === 0) return;
     setAdding(true);
     try {
+      const existing = await getExistingModelNames();
+      let added = 0;
       for (const name of selectedModels) {
+        if (existing.has(name)) continue;
         const model = scannedModels.find((m) => m.name === name);
         await httpClient.createProviderLLMModel({
           name,
@@ -1215,10 +1228,12 @@ function WizardModelScan({
           context_length: model?.context_length ?? null,
           extra_args: {},
         } as never);
+        existing.add(name);
+        added++;
+      }
+      if (added > 0) {
+        toast.success(t('wizard.provider.modelsAdded', { count: added }));
       }
-      toast.success(
-        t('wizard.provider.modelsAdded', { count: selectedModels.size }),
-      );
       setAddedModelNames((prev) => {
         const next = new Set(prev);
         for (const name of selectedModels) next.add(name);
@@ -1238,6 +1253,12 @@ function WizardModelScan({
     if (!providerUuid || !name) return;
     setManualAdding(true);
     try {
+      const existing = await getExistingModelNames();
+      if (existing.has(name)) {
+        toast.error(t('wizard.provider.modelAlreadyExists', { name }));
+        setManualAdding(false);
+        return;
+      }
       await httpClient.createProviderLLMModel({
         name,
         provider_uuid: providerUuid,
diff --git a/web/src/i18n/locales/en-US.ts b/web/src/i18n/locales/en-US.ts
index 968f4a67d..861c02c78 100644
--- a/web/src/i18n/locales/en-US.ts
+++ b/web/src/i18n/locales/en-US.ts
@@ -1874,6 +1874,7 @@ const enUS = {
       addManual: 'Add',
       saveAndNext: 'Save & Next',
       alreadyAdded: 'Added',
+      modelAlreadyExists: 'Model "{{name}}" already exists',
     },
     modelSource: {
       title: 'Choose Model Source',
diff --git a/web/src/i18n/locales/es-ES.ts b/web/src/i18n/locales/es-ES.ts
index 6895579e6..9a6421b21 100644
--- a/web/src/i18n/locales/es-ES.ts
+++ b/web/src/i18n/locales/es-ES.ts
@@ -1732,6 +1732,7 @@ const esES = {
       addManual: 'Agregar',
       saveAndNext: 'Guardar y siguiente',
       alreadyAdded: 'Agregado',
+      modelAlreadyExists: 'El modelo "{{name}}" ya existe',
     },
     modelSource: {
       title: 'Elegir fuente del modelo',
diff --git a/web/src/i18n/locales/ja-JP.ts b/web/src/i18n/locales/ja-JP.ts
index 1404b9996..3f91feea4 100644
--- a/web/src/i18n/locales/ja-JP.ts
+++ b/web/src/i18n/locales/ja-JP.ts
@@ -1793,6 +1793,7 @@ const jaJP = {
       addManual: '追加',
       saveAndNext: '保存して次へ',
       alreadyAdded: '追加済み',
+      modelAlreadyExists: 'モデル「{{name}}」は既に存在します',
     },
     modelSource: {
       title: 'モデルソースを選択',
diff --git a/web/src/i18n/locales/ru-RU.ts b/web/src/i18n/locales/ru-RU.ts
index 07d82b9f8..c85579c2a 100644
--- a/web/src/i18n/locales/ru-RU.ts
+++ b/web/src/i18n/locales/ru-RU.ts
@@ -1702,6 +1702,7 @@ const ruRU = {
       addManual: 'Добавить',
       saveAndNext: 'Сохранить и далее',
       alreadyAdded: 'Добавлено',
+      modelAlreadyExists: 'Модель "{{name}}" уже существует',
     },
     modelSource: {
       title: 'Выберите источник модели',
diff --git a/web/src/i18n/locales/th-TH.ts b/web/src/i18n/locales/th-TH.ts
index 9e591db36..06eaa0574 100644
--- a/web/src/i18n/locales/th-TH.ts
+++ b/web/src/i18n/locales/th-TH.ts
@@ -1666,6 +1666,7 @@ const thTH = {
       addManual: 'เพิ่ม',
       saveAndNext: 'บันทึกและถัดไป',
       alreadyAdded: 'เพิ่มแล้ว',
+      modelAlreadyExists: 'โมเดล "{{name}}" มีอยู่แล้ว',
     },
     modelSource: {
       title: 'เลือกแหล่งโมเดล',
diff --git a/web/src/i18n/locales/vi-VN.ts b/web/src/i18n/locales/vi-VN.ts
index 057512422..9f7f200cd 100644
--- a/web/src/i18n/locales/vi-VN.ts
+++ b/web/src/i18n/locales/vi-VN.ts
@@ -1692,6 +1692,7 @@ const viVN = {
       addManual: 'Thêm',
       saveAndNext: 'Lưu & Tiếp theo',
       alreadyAdded: 'Đã thêm',
+      modelAlreadyExists: 'Mô hình "{{name}}" đã tồn tại',
     },
     modelSource: {
       title: 'Chọn nguồn mô hình',
diff --git a/web/src/i18n/locales/zh-Hans.ts b/web/src/i18n/locales/zh-Hans.ts
index c02ff3fa8..23866fb14 100644
--- a/web/src/i18n/locales/zh-Hans.ts
+++ b/web/src/i18n/locales/zh-Hans.ts
@@ -1790,6 +1790,7 @@ const zhHans = {
       addManual: '添加',
       saveAndNext: '保存并下一步',
       alreadyAdded: '已添加',
+      modelAlreadyExists: '模型 "{{name}}" 已存在',
     },
     modelSource: {
       title: '选择模型来源',
diff --git a/web/src/i18n/locales/zh-Hant.ts b/web/src/i18n/locales/zh-Hant.ts
index a7c096a8a..ce8568374 100644
--- a/web/src/i18n/locales/zh-Hant.ts
+++ b/web/src/i18n/locales/zh-Hant.ts
@@ -1613,6 +1613,7 @@ const zhHant = {
       addManual: '新增',
       saveAndNext: '儲存並下一步',
       alreadyAdded: '已新增',
+      modelAlreadyExists: '模型「{{name}}」已存在',
     },
     modelSource: {
       title: '選擇模型來源',