diff --git a/frontend/src/lib/components/MarkdownStatusBadge.svelte b/frontend/src/lib/components/MarkdownStatusBadge.svelte
index c73c29c..e4f8a88 100644
--- a/frontend/src/lib/components/MarkdownStatusBadge.svelte
+++ b/frontend/src/lib/components/MarkdownStatusBadge.svelte
@@ -77,6 +77,7 @@
       case 'processing':
         return { tone: 'accent', label: 'Markdown 변환 중', tooltip: null };
       case 'success':
+      case 'completed': // API field_validator 가 DB 'success'→'completed' remap (S1 backend) — 동의어
         return {
           tone: 'success',
           label: 'Markdown',
diff --git a/frontend/src/lib/utils/mdStatus.ts b/frontend/src/lib/utils/mdStatus.ts
new file mode 100644
index 0000000..6311e82
--- /dev/null
+++ b/frontend/src/lib/utils/mdStatus.ts
@@ -0,0 +1,25 @@
+// md_status 어휘 단일 source.
+//
+// DB CHECK enum 은 'success' 이지만, API 직렬화 시 field_validator
+// `_db_success_to_completed`(app/api/documents.py) 가 'success' → 'completed' 로 remap 한다
+// (S1 backend). 나머지 상태(pending/processing/partial/skipped/failed)는 양쪽 동일.
+//
+// 따라서 프론트는 두 어휘를 모두 "성공" 으로 취급해야 S1 backend 배포 전(API='success')·
+// 후(API='completed') 모두 안전하다. (DB↔API enum divergence guard — md_status 비교는
+// 반드시 이 헬퍼 경유, raw `=== 'success'` / `=== 'completed'` 산재 금지.)
+
+/** DB 'success' 또는 API 'completed' = 변환 성공(markdown 준비됨). */
+export function isMdSuccess(status: string | null | undefined): boolean {
+  return status === 'success' || status === 'completed';
+}
+
+/** md상태 칩 렌더 대상 상태. pending/null 은 숨김(legacy 대량 노이즈 회피). */
+export function isMdStatusVisible(status: string | null | undefined): boolean {
+  return (
+    status === 'processing' ||
+    isMdSuccess(status) ||
+    status === 'partial' ||
+    status === 'skipped' ||
+    status === 'failed'
+  );
+}
diff --git a/frontend/src/routes/documents/+page.svelte b/frontend/src/routes/documents/+page.svelte
index 0e2604f..1f2d96d 100644
--- a/frontend/src/routes/documents/+page.svelte
+++ b/frontend/src/routes/documents/+page.svelte
@@ -11,6 +11,7 @@
   import { Info, X, Plus, Trash2, Tag, FolderTree, Sparkles, ChevronLeft, ArrowUpDown } from 'lucide-svelte';
   import DocumentViewer from '$lib/components/DocumentViewer.svelte';
   import MarkdownStatusBadge from '$lib/components/MarkdownStatusBadge.svelte';
+  import { isMdStatusVisible } from '$lib/utils/mdStatus';
   import UploadDropzone from '$lib/components/UploadDropzone.svelte';
   import Drawer from '$lib/components/ui/Drawer.svelte';
   import Modal from '$lib/components/ui/Modal.svelte';
@@ -679,7 +680,7 @@
         {#if doc.ai_sub_group}<div class="flex justify-between gap-2 text-xs py-1"><span class="text-dim">하위</span><span class="text-text font-medium text-right truncate">{doc.ai_sub_group}</span></div>{/if}
         <div class="flex justify-between gap-2 text-xs py-1"><span class="text-dim">수정</span><span class="text-text font-medium text-right">{shortDate(doc.updated_at || doc.created_at)}</span></div>
         {#if size}<div class="flex justify-between gap-2 text-xs py-1"><span class="text-dim">원본</span><span class="text-text font-medium text-right">{size}</span></div>{/if}
-        {#if ['processing', 'success', 'partial', 'skipped', 'failed'].includes(doc.md_status)}<div class="flex items-center justify-between gap-2 text-xs py-1"><span class="text-dim">md 상태</span><MarkdownStatusBadge mdStatus={doc.md_status} mdExtractionError={doc.md_extraction_error} mdExtractionQuality={doc.md_extraction_quality} /></div>{/if}
+        {#if isMdStatusVisible(doc.md_status)}<div class="flex items-center justify-between gap-2 text-xs py-1"><span class="text-dim">md 상태</span><MarkdownStatusBadge mdStatus={doc.md_status} mdExtractionError={doc.md_extraction_error} mdExtractionQuality={doc.md_extraction_quality} /></div>{/if}
         {#if doc.read_count}<div class="flex justify-between gap-2 text-xs py-1"><span class="text-dim">읽음</span><span class="text-text font-medium text-right">{doc.read_count}회</span></div>{/if}
       </div>
     </div>
diff --git a/frontend/src/routes/documents/[id]/+page.svelte b/frontend/src/routes/documents/[id]/+page.svelte
index 3ab8d40..40ad723 100644
--- a/frontend/src/routes/documents/[id]/+page.svelte
+++ b/frontend/src/routes/documents/[id]/+page.svelte
@@ -6,6 +6,7 @@
   import { page } from '$app/stores';
   import { goto } from '$app/navigation';
   import { api, getAccessToken } from '$lib/api';
+  import { isMdSuccess } from '$lib/utils/mdStatus';
   import { addToast } from '$lib/stores/toast';
   import { marked } from 'marked';
   import DOMPurify from 'dompurify';
@@ -147,7 +148,7 @@
   let pdfViewMode = $state('markdown'); // 'markdown' | 'pdf'
   let lastDocId = $state(null);
   let canShowMarkdown = $derived(
-    !!(doc?.md_status === 'success' && doc?.md_content?.trim())
+    !!(isMdSuccess(doc?.md_status) && doc?.md_content?.trim())
   );
 
   $effect(() => {