diff --git a/app/src/components/intelligence/VaultPanel.test.tsx b/app/src/components/intelligence/VaultPanel.test.tsx
index e44fc4c97..96e63c2b2 100644
--- a/app/src/components/intelligence/VaultPanel.test.tsx
+++ b/app/src/components/intelligence/VaultPanel.test.tsx
@@ -41,6 +41,8 @@ function vault(overrides: Record<string, unknown> = {}) {
     created_at: '2026-05-17T10:00:00Z',
     last_synced_at: null,
     file_count: 0,
+    write_state: 'writable',
+    write_state_reason: 'writable',
     ...overrides,
   };
 }
@@ -111,6 +113,35 @@ describe('<VaultPanel />', () => {
     expect(screen.getByText('A')).toBeTruthy();
     expect(screen.getByText(/42 file/)).toBeTruthy();
     expect(screen.getByText(/synced 30s ago/)).toBeTruthy();
+    expect(screen.getByTestId('vault-write-state-v-A')).toHaveTextContent('Writable');
+    expect(screen.getByText(/Approved markdown/)).toBeTruthy();
+  });
+
+  it('shows read-only and unavailable vault write states with reasons', async () => {
+    mockList.mockResolvedValueOnce({
+      result: [
+        vault({
+          id: 'v-readonly',
+          name: 'Read only',
+          write_state: 'read_only',
+          write_state_reason: 'read_only',
+        }),
+        vault({
+          id: 'v-missing',
+          name: 'Missing',
+          write_state: 'unavailable',
+          write_state_reason: 'unavailable',
+        }),
+      ],
+      logs: [],
+    });
+    render(<VaultPanel />);
+    await waitFor(() => screen.getByTestId('vault-list'));
+
+    expect(screen.getByTestId('vault-write-state-v-readonly')).toHaveTextContent('Read-only');
+    expect(screen.getByText('Vault folder is read-only on this device.')).toBeTruthy();
+    expect(screen.getByTestId('vault-write-state-v-missing')).toHaveTextContent('Unavailable');
+    expect(screen.getByText('Vault folder is not available on this device.')).toBeTruthy();
   });
 
   it('toggles the add form and creates a vault on submit', async () => {
diff --git a/app/src/components/intelligence/VaultPanel.tsx b/app/src/components/intelligence/VaultPanel.tsx
index 9311a732e..e85b8d064 100644
--- a/app/src/components/intelligence/VaultPanel.tsx
+++ b/app/src/components/intelligence/VaultPanel.tsx
@@ -359,6 +359,12 @@ export function VaultPanel({ onToast }: VaultPanelProps) {
         <ul className="divide-y divide-stone-100 dark:divide-neutral-800" data-testid="vault-list">
           {vaults.map(v => {
             const state = busy[v.id];
+            const writeStateReason = v.write_state_reason
+              ? t(
+                  `vault.writeState.reasons.${v.write_state_reason}`,
+                  t('vault.writeState.unknownReason')
+                )
+              : t('vault.writeState.unknownReason');
             return (
               <li key={v.id} className="flex items-center justify-between gap-3 py-2">
                 <div className="min-w-0 flex-1">
@@ -379,6 +385,17 @@ export function VaultPanel({ onToast }: VaultPanelProps) {
                         )
                       : t('vault.neverSynced')}
                   </div>
+                  <div className="mt-1 flex flex-wrap items-center gap-1.5">
+                    <span
+                      className={writeStateBadgeClass(v.write_state)}
+                      title={writeStateReason}
+                      data-testid={`vault-write-state-${v.id}`}>
+                      {t(`vault.writeState.${v.write_state}`)}
+                    </span>
+                    <span className="text-[11px] text-stone-400 dark:text-neutral-500">
+                      {writeStateReason}
+                    </span>
+                  </div>
                 </div>
                 <div className="flex items-center gap-2">
                   <button
@@ -425,6 +442,19 @@ export function VaultPanel({ onToast }: VaultPanelProps) {
   );
 }
 
+function writeStateBadgeClass(state: CoreVault['write_state']): string {
+  const base = 'inline-flex h-5 items-center rounded px-1.5 text-[10px] font-semibold';
+  switch (state) {
+    case 'writable':
+      return `${base} bg-sage-50 text-sage-700 dark:bg-sage-500/10 dark:text-sage-300`;
+    case 'read_only':
+      return `${base} bg-amber-50 text-amber-700 dark:bg-amber-500/10 dark:text-amber-300`;
+    case 'unavailable':
+    default:
+      return `${base} bg-coral-50 text-coral-700 dark:bg-coral-500/10 dark:text-coral-300`;
+  }
+}
+
 function formatRelative(iso: string, translate: (key: string) => string): string {
   const timestamp = new Date(iso).getTime();
   if (Number.isNaN(timestamp)) return iso;
diff --git a/app/src/lib/i18n/ar.ts b/app/src/lib/i18n/ar.ts
index 052652850..461dd407f 100644
--- a/app/src/lib/i18n/ar.ts
+++ b/app/src/lib/i18n/ar.ts
@@ -4041,6 +4041,16 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} ملف (ملفات)',
   'vault.syncedRelative': 'تمت مزامنته {time}',
   'vault.neverSynced': 'لم تتم مزامنته أبدًا',
+  'vault.writeState.writable': 'قابل للكتابة',
+  'vault.writeState.read_only': 'للقراءة فقط',
+  'vault.writeState.unavailable': 'غير متاح',
+  'vault.writeState.unknownReason': 'حالة الكتابة غير معروفة.',
+  'vault.writeState.reasons.writable':
+    'يمكن حفظ عمليات كتابة Markdown/wiki الموافق عليها في هذا المخزن.',
+  'vault.writeState.reasons.read_only': 'مجلد المخزن للقراءة فقط على هذا الجهاز.',
+  'vault.writeState.reasons.unavailable': 'مجلد المخزن غير متاح على هذا الجهاز.',
+  'vault.writeState.reasons.not_directory': 'مسار المخزن ليس دليلاً.',
+  'vault.writeState.reasons.empty_path': 'مسار مجلد المخزن فارغ.',
   'vault.syncingProgress': 'جارٍ المزامنة… {ingested}/{total}',
   'vault.removing': 'جارٍ الإزالة...',
   'vault.relative.sec': 'قبل {count}s',
diff --git a/app/src/lib/i18n/bn.ts b/app/src/lib/i18n/bn.ts
index e15500f82..751746fe4 100644
--- a/app/src/lib/i18n/bn.ts
+++ b/app/src/lib/i18n/bn.ts
@@ -4107,6 +4107,15 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} ফাইল(গুলি)',
   'vault.syncedRelative': 'সিঙ্ক করা হয়েছে {time}',
   'vault.neverSynced': 'কখনই সিঙ্ক করা হয়নি',
+  'vault.writeState.writable': 'লেখার যোগ্য',
+  'vault.writeState.read_only': 'শুধু-পঠন',
+  'vault.writeState.unavailable': 'অনুপলব্ধ',
+  'vault.writeState.unknownReason': 'লেখার অবস্থা অজানা।',
+  'vault.writeState.reasons.writable': 'অনুমোদিত Markdown/wiki লেখা এই ভল্টে সংরক্ষণ করা যাবে।',
+  'vault.writeState.reasons.read_only': 'এই ডিভাইসে ভল্ট ফোল্ডারটি শুধু-পঠন।',
+  'vault.writeState.reasons.unavailable': 'এই ডিভাইসে ভল্ট ফোল্ডারটি উপলব্ধ নয়।',
+  'vault.writeState.reasons.not_directory': 'ভল্ট পাথটি কোনো ফোল্ডার নয়।',
+  'vault.writeState.reasons.empty_path': 'ভল্ট ফোল্ডার পাথ খালি।',
   'vault.syncingProgress': 'সিঙ্ক হচ্ছে... {ingested}/{total}',
   'vault.removing': 'সরানো হচ্ছে...',
   'vault.relative.sec': '{count}সেকেন্ড আগে',
diff --git a/app/src/lib/i18n/de.ts b/app/src/lib/i18n/de.ts
index 18f689ec4..658343899 100644
--- a/app/src/lib/i18n/de.ts
+++ b/app/src/lib/i18n/de.ts
@@ -4220,6 +4220,16 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} Datei(en)',
   'vault.syncedRelative': 'synchronisiert {time}',
   'vault.neverSynced': 'nie synchronisiert',
+  'vault.writeState.writable': 'Beschreibbar',
+  'vault.writeState.read_only': 'Schreibgeschützt',
+  'vault.writeState.unavailable': 'Nicht verfügbar',
+  'vault.writeState.unknownReason': 'Schreibstatus ist unbekannt.',
+  'vault.writeState.reasons.writable':
+    'Genehmigte Markdown-/Wiki-Schreibvorgänge können in diesem Tresor gespeichert werden.',
+  'vault.writeState.reasons.read_only': 'Der Tresorordner ist auf diesem Gerät schreibgeschützt.',
+  'vault.writeState.reasons.unavailable': 'Der Tresorordner ist auf diesem Gerät nicht verfügbar.',
+  'vault.writeState.reasons.not_directory': 'Der Tresorpfad ist kein Ordner.',
+  'vault.writeState.reasons.empty_path': 'Der Tresorordnerpfad ist leer.',
   'vault.syncingProgress': 'Synchronisierung… {ingested}/{total}',
   'vault.removing': 'Entfernen…',
   'vault.relative.sec': 'vor {count}s',
diff --git a/app/src/lib/i18n/en.ts b/app/src/lib/i18n/en.ts
index ca2b42371..f2d481d2e 100644
--- a/app/src/lib/i18n/en.ts
+++ b/app/src/lib/i18n/en.ts
@@ -4323,6 +4323,15 @@ const en: TranslationMap = {
   'vault.fileCount': '{count} file(s)',
   'vault.syncedRelative': 'synced {time}',
   'vault.neverSynced': 'never synced',
+  'vault.writeState.writable': 'Writable',
+  'vault.writeState.read_only': 'Read-only',
+  'vault.writeState.unavailable': 'Unavailable',
+  'vault.writeState.unknownReason': 'Write state is unknown.',
+  'vault.writeState.reasons.writable': 'Approved markdown/wiki writes can be saved in this vault.',
+  'vault.writeState.reasons.read_only': 'Vault folder is read-only on this device.',
+  'vault.writeState.reasons.unavailable': 'Vault folder is not available on this device.',
+  'vault.writeState.reasons.not_directory': 'Vault path is not a directory.',
+  'vault.writeState.reasons.empty_path': 'Vault folder path is empty.',
   'vault.syncingProgress': 'Syncing… {ingested}/{total}',
   'vault.removing': 'Removing…',
   'vault.relative.sec': '{count}s ago',
diff --git a/app/src/lib/i18n/es.ts b/app/src/lib/i18n/es.ts
index 947289e04..c43b5e5e9 100644
--- a/app/src/lib/i18n/es.ts
+++ b/app/src/lib/i18n/es.ts
@@ -4185,6 +4185,18 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} archivo(s)',
   'vault.syncedRelative': 'sincronizado {time}',
   'vault.neverSynced': 'nunca sincronizado',
+  'vault.writeState.writable': 'Editable',
+  'vault.writeState.read_only': 'Solo lectura',
+  'vault.writeState.unavailable': 'No disponible',
+  'vault.writeState.unknownReason': 'Se desconoce el estado de escritura.',
+  'vault.writeState.reasons.writable':
+    'Las escrituras Markdown/wiki aprobadas se pueden guardar en esta bóveda.',
+  'vault.writeState.reasons.read_only':
+    'La carpeta de la bóveda es de solo lectura en este dispositivo.',
+  'vault.writeState.reasons.unavailable':
+    'La carpeta de la bóveda no está disponible en este dispositivo.',
+  'vault.writeState.reasons.not_directory': 'La ruta de la bóveda no es una carpeta.',
+  'vault.writeState.reasons.empty_path': 'La ruta de la carpeta de la bóveda está vacía.',
   'vault.syncingProgress': 'Sincronizando... {ingested}/{total}',
   'vault.removing': 'Eliminando…',
   'vault.relative.sec': 'Hace {count}s',
diff --git a/app/src/lib/i18n/fr.ts b/app/src/lib/i18n/fr.ts
index 709f99774..4b2c67c52 100644
--- a/app/src/lib/i18n/fr.ts
+++ b/app/src/lib/i18n/fr.ts
@@ -4202,6 +4202,18 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} fichier(s)',
   'vault.syncedRelative': 'synchronisés {time}',
   'vault.neverSynced': 'jamais synchronisés',
+  'vault.writeState.writable': 'Modifiable',
+  'vault.writeState.read_only': 'Lecture seule',
+  'vault.writeState.unavailable': 'Indisponible',
+  'vault.writeState.unknownReason': "L'état d'écriture est inconnu.",
+  'vault.writeState.reasons.writable':
+    'Les écritures Markdown/wiki approuvées peuvent être enregistrées dans ce coffre.',
+  'vault.writeState.reasons.read_only':
+    'Le dossier du coffre est en lecture seule sur cet appareil.',
+  'vault.writeState.reasons.unavailable':
+    "Le dossier du coffre n'est pas disponible sur cet appareil.",
+  'vault.writeState.reasons.not_directory': "Le chemin du coffre n'est pas un dossier.",
+  'vault.writeState.reasons.empty_path': 'Le chemin du dossier du coffre est vide.',
   'vault.syncingProgress': 'Synchronisation… {ingested}/{total}',
   'vault.removing': 'Suppression…',
   'vault.relative.sec': 'il y a {count}s',
diff --git a/app/src/lib/i18n/hi.ts b/app/src/lib/i18n/hi.ts
index f7115134c..466b820fc 100644
--- a/app/src/lib/i18n/hi.ts
+++ b/app/src/lib/i18n/hi.ts
@@ -4116,6 +4116,15 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count}फ़ाइलें',
   'vault.syncedRelative': 'समन्वयित {time}',
   'vault.neverSynced': 'कभी समन्वयित नहीं किया गया',
+  'vault.writeState.writable': 'लिखने योग्य',
+  'vault.writeState.read_only': 'केवल पढ़ने योग्य',
+  'vault.writeState.unavailable': 'उपलब्ध नहीं',
+  'vault.writeState.unknownReason': 'लिखने की स्थिति अज्ञात है.',
+  'vault.writeState.reasons.writable': 'स्वीकृत Markdown/wiki लेखन इस वॉल्ट में सहेजे जा सकते हैं।',
+  'vault.writeState.reasons.read_only': 'इस डिवाइस पर वॉल्ट फ़ोल्डर केवल पढ़ने योग्य है।',
+  'vault.writeState.reasons.unavailable': 'इस डिवाइस पर वॉल्ट फ़ोल्डर उपलब्ध नहीं है।',
+  'vault.writeState.reasons.not_directory': 'वॉल्ट पथ कोई फ़ोल्डर नहीं है।',
+  'vault.writeState.reasons.empty_path': 'वॉल्ट फ़ोल्डर पथ खाली है।',
   'vault.syncingProgress': 'सिंक हो रहा है... {ingested}/{total}',
   'vault.removing': 'हटाया जा रहा है...',
   'vault.relative.sec': '{count}s पहले',
diff --git a/app/src/lib/i18n/id.ts b/app/src/lib/i18n/id.ts
index 954a6680f..3ece78e61 100644
--- a/app/src/lib/i18n/id.ts
+++ b/app/src/lib/i18n/id.ts
@@ -4125,6 +4125,16 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} file',
   'vault.syncedRelative': 'disinkronkan {time}',
   'vault.neverSynced': 'tidak pernah disinkronkan',
+  'vault.writeState.writable': 'Dapat ditulis',
+  'vault.writeState.read_only': 'Hanya baca',
+  'vault.writeState.unavailable': 'Tidak tersedia',
+  'vault.writeState.unknownReason': 'Status tulis tidak diketahui.',
+  'vault.writeState.reasons.writable':
+    'Penulisan Markdown/wiki yang disetujui dapat disimpan di vault ini.',
+  'vault.writeState.reasons.read_only': 'Folder vault hanya baca di perangkat ini.',
+  'vault.writeState.reasons.unavailable': 'Folder vault tidak tersedia di perangkat ini.',
+  'vault.writeState.reasons.not_directory': 'Jalur vault bukan folder.',
+  'vault.writeState.reasons.empty_path': 'Jalur folder vault kosong.',
   'vault.syncingProgress': 'Menyinkronkan… {ingested}/{total}',
   'vault.removing': 'Menghapus…',
   'vault.relative.sec': '{count}s yang lalu',
diff --git a/app/src/lib/i18n/it.ts b/app/src/lib/i18n/it.ts
index c2e657dc5..c13774727 100644
--- a/app/src/lib/i18n/it.ts
+++ b/app/src/lib/i18n/it.ts
@@ -4178,6 +4178,18 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} file',
   'vault.syncedRelative': 'sincronizzato {time}',
   'vault.neverSynced': 'mai sincronizzato',
+  'vault.writeState.writable': 'Scrivibile',
+  'vault.writeState.read_only': 'Sola lettura',
+  'vault.writeState.unavailable': 'Non disponibile',
+  'vault.writeState.unknownReason': 'Stato di scrittura sconosciuto.',
+  'vault.writeState.reasons.writable':
+    'Le scritture Markdown/wiki approvate possono essere salvate in questo deposito.',
+  'vault.writeState.reasons.read_only':
+    'La cartella del deposito è in sola lettura su questo dispositivo.',
+  'vault.writeState.reasons.unavailable':
+    'La cartella del deposito non è disponibile su questo dispositivo.',
+  'vault.writeState.reasons.not_directory': 'Il percorso del deposito non è una cartella.',
+  'vault.writeState.reasons.empty_path': 'Il percorso della cartella del deposito è vuoto.',
   'vault.syncingProgress': 'Sincronizzazione… {ingested}/{total}',
   'vault.removing': 'Rimozione in corso…',
   'vault.relative.sec': '{count}s fa',
diff --git a/app/src/lib/i18n/ko.ts b/app/src/lib/i18n/ko.ts
index e3f59391e..66860c3ad 100644
--- a/app/src/lib/i18n/ko.ts
+++ b/app/src/lib/i18n/ko.ts
@@ -4076,6 +4076,15 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} 파일',
   'vault.syncedRelative': '동기화됨 {time}',
   'vault.neverSynced': '동기화되지 않음',
+  'vault.writeState.writable': '쓰기 가능',
+  'vault.writeState.read_only': '읽기 전용',
+  'vault.writeState.unavailable': '사용할 수 없음',
+  'vault.writeState.unknownReason': '쓰기 상태를 알 수 없습니다.',
+  'vault.writeState.reasons.writable': '승인된 Markdown/wiki 쓰기를 이 볼트에 저장할 수 있습니다.',
+  'vault.writeState.reasons.read_only': '이 장치에서 볼트 폴더는 읽기 전용입니다.',
+  'vault.writeState.reasons.unavailable': '이 장치에서 볼트 폴더를 사용할 수 없습니다.',
+  'vault.writeState.reasons.not_directory': '볼트 경로가 폴더가 아닙니다.',
+  'vault.writeState.reasons.empty_path': '볼트 폴더 경로가 비어 있습니다.',
   'vault.syncingProgress': '동기화 중… {ingested}/{total}',
   'vault.removing': '제거 중…',
   'vault.relative.sec': '{count}초 전',
diff --git a/app/src/lib/i18n/pl.ts b/app/src/lib/i18n/pl.ts
index 6038a26d9..5b1235fec 100644
--- a/app/src/lib/i18n/pl.ts
+++ b/app/src/lib/i18n/pl.ts
@@ -4180,6 +4180,16 @@ const messages: TranslationMap = {
   'vault.fileCount': 'Plików: {count}',
   'vault.syncedRelative': 'zsynchronizowano {time}',
   'vault.neverSynced': 'nigdy nie synchronizowano',
+  'vault.writeState.writable': 'Zapisywalny',
+  'vault.writeState.read_only': 'Tylko do odczytu',
+  'vault.writeState.unavailable': 'Niedostępny',
+  'vault.writeState.unknownReason': 'Stan zapisu jest nieznany.',
+  'vault.writeState.reasons.writable':
+    'Zatwierdzone zapisy Markdown/wiki mogą być zapisane w tym skarbcu.',
+  'vault.writeState.reasons.read_only': 'Folder skarbca jest tylko do odczytu na tym urządzeniu.',
+  'vault.writeState.reasons.unavailable': 'Folder skarbca jest niedostępny na tym urządzeniu.',
+  'vault.writeState.reasons.not_directory': 'Ścieżka skarbca nie jest folderem.',
+  'vault.writeState.reasons.empty_path': 'Ścieżka folderu skarbca jest pusta.',
   'vault.syncingProgress': 'Synchronizowanie… {ingested}/{total}',
   'vault.removing': 'Usuwanie…',
   'vault.relative.sec': '{count} s temu',
diff --git a/app/src/lib/i18n/pt.ts b/app/src/lib/i18n/pt.ts
index e2c33ec2c..1f87368d9 100644
--- a/app/src/lib/i18n/pt.ts
+++ b/app/src/lib/i18n/pt.ts
@@ -4179,6 +4179,16 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} arquivo(s)',
   'vault.syncedRelative': 'sincronizado {time}',
   'vault.neverSynced': 'nunca sincronizado',
+  'vault.writeState.writable': 'Gravável',
+  'vault.writeState.read_only': 'Somente leitura',
+  'vault.writeState.unavailable': 'Indisponível',
+  'vault.writeState.unknownReason': 'Estado de gravação desconhecido.',
+  'vault.writeState.reasons.writable':
+    'Gravações Markdown/wiki aprovadas podem ser salvas neste cofre.',
+  'vault.writeState.reasons.read_only': 'A pasta do cofre é somente leitura neste dispositivo.',
+  'vault.writeState.reasons.unavailable': 'A pasta do cofre não está disponível neste dispositivo.',
+  'vault.writeState.reasons.not_directory': 'O caminho do cofre não é uma pasta.',
+  'vault.writeState.reasons.empty_path': 'O caminho da pasta do cofre está vazio.',
   'vault.syncingProgress': 'Sincronizando… {ingested}/{total}',
   'vault.removing': 'Removendo…',
   'vault.relative.sec': '{count}s atrás',
diff --git a/app/src/lib/i18n/ru.ts b/app/src/lib/i18n/ru.ts
index 279511a68..97c984d0a 100644
--- a/app/src/lib/i18n/ru.ts
+++ b/app/src/lib/i18n/ru.ts
@@ -4146,6 +4146,17 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} файлов',
   'vault.syncedRelative': 'синхронизировано {time}',
   'vault.neverSynced': 'никогда не синхронизировано',
+  'vault.writeState.writable': 'Доступно для записи',
+  'vault.writeState.read_only': 'Только чтение',
+  'vault.writeState.unavailable': 'Недоступно',
+  'vault.writeState.unknownReason': 'Статус записи неизвестен.',
+  'vault.writeState.reasons.writable':
+    'Одобренные записи Markdown/wiki можно сохранить в этом хранилище.',
+  'vault.writeState.reasons.read_only':
+    'Папка хранилища доступна только для чтения на этом устройстве.',
+  'vault.writeState.reasons.unavailable': 'Папка хранилища недоступна на этом устройстве.',
+  'vault.writeState.reasons.not_directory': 'Путь хранилища не является папкой.',
+  'vault.writeState.reasons.empty_path': 'Путь к папке хранилища пуст.',
   'vault.syncingProgress': 'Синхронизация… {ingested}/{total}',
   'vault.removing': 'Удаление…',
   'vault.relative.sec': '{count}s назад',
diff --git a/app/src/lib/i18n/zh-CN.ts b/app/src/lib/i18n/zh-CN.ts
index ec5b22da2..f73a20dfa 100644
--- a/app/src/lib/i18n/zh-CN.ts
+++ b/app/src/lib/i18n/zh-CN.ts
@@ -3915,6 +3915,15 @@ const messages: TranslationMap = {
   'vault.fileCount': '{count} 文件',
   'vault.syncedRelative': '已同步 {time}',
   'vault.neverSynced': '从未同步过',
+  'vault.writeState.writable': '可写',
+  'vault.writeState.read_only': '只读',
+  'vault.writeState.unavailable': '不可用',
+  'vault.writeState.unknownReason': '写入状态未知。',
+  'vault.writeState.reasons.writable': '可将已批准的 Markdown/wiki 写入保存到此保险库。',
+  'vault.writeState.reasons.read_only': '此设备上的保险库文件夹是只读的。',
+  'vault.writeState.reasons.unavailable': '此设备上的保险库文件夹不可用。',
+  'vault.writeState.reasons.not_directory': '保险库路径不是文件夹。',
+  'vault.writeState.reasons.empty_path': '保险库文件夹路径为空。',
   'vault.syncingProgress': '正在同步... {ingested}/{total}',
   'vault.removing': '正在删除...',
   'vault.relative.sec': '{count} 秒前',
diff --git a/app/src/utils/tauriCommands/vault.test.ts b/app/src/utils/tauriCommands/vault.test.ts
index 39d4429e4..6fdf52cdc 100644
--- a/app/src/utils/tauriCommands/vault.test.ts
+++ b/app/src/utils/tauriCommands/vault.test.ts
@@ -21,6 +21,7 @@ describe('tauriCommands/vault', () => {
   let openhumanVaultCreate: typeof import('./vault').openhumanVaultCreate;
   let openhumanVaultGet: typeof import('./vault').openhumanVaultGet;
   let openhumanVaultFiles: typeof import('./vault').openhumanVaultFiles;
+  let openhumanVaultWriteMarkdown: typeof import('./vault').openhumanVaultWriteMarkdown;
   let openhumanVaultRemove: typeof import('./vault').openhumanVaultRemove;
   let openhumanVaultSync: typeof import('./vault').openhumanVaultSync;
   let openhumanVaultSyncStatus: typeof import('./vault').openhumanVaultSyncStatus;
@@ -33,6 +34,7 @@ describe('tauriCommands/vault', () => {
     openhumanVaultCreate = actual.openhumanVaultCreate;
     openhumanVaultGet = actual.openhumanVaultGet;
     openhumanVaultFiles = actual.openhumanVaultFiles;
+    openhumanVaultWriteMarkdown = actual.openhumanVaultWriteMarkdown;
     openhumanVaultRemove = actual.openhumanVaultRemove;
     openhumanVaultSync = actual.openhumanVaultSync;
     openhumanVaultSyncStatus = actual.openhumanVaultSyncStatus;
@@ -127,6 +129,44 @@ describe('tauriCommands/vault', () => {
     });
   });
 
+  describe('openhumanVaultWriteMarkdown', () => {
+    test('throws when not running in Tauri', async () => {
+      mockIsTauri.mockReturnValue(false);
+      await expect(
+        openhumanVaultWriteMarkdown({
+          vaultId: 'v-1',
+          relPath: 'wiki/a.md',
+          content: '# A',
+          approved: true,
+        })
+      ).rejects.toThrow('Not running in Tauri');
+    });
+
+    test('dispatches openhuman.vault_write_markdown with approval state', async () => {
+      mockCallCoreRpc.mockResolvedValue({
+        result: { vault_id: 'v-1', rel_path: 'wiki/a.md', bytes_written: 3, created: true },
+        logs: [],
+      });
+      await openhumanVaultWriteMarkdown({
+        vaultId: 'v-1',
+        relPath: 'wiki/a.md',
+        content: '# A',
+        overwrite: true,
+        approved: true,
+      });
+      expect(mockCallCoreRpc).toHaveBeenCalledWith({
+        method: 'openhuman.vault_write_markdown',
+        params: {
+          vault_id: 'v-1',
+          rel_path: 'wiki/a.md',
+          content: '# A',
+          overwrite: true,
+          approved: true,
+        },
+      });
+    });
+  });
+
   describe('openhumanVaultRemove', () => {
     test('throws when not running in Tauri', async () => {
       mockIsTauri.mockReturnValue(false);
diff --git a/app/src/utils/tauriCommands/vault.ts b/app/src/utils/tauriCommands/vault.ts
index 52b848739..b6312c9b9 100644
--- a/app/src/utils/tauriCommands/vault.ts
+++ b/app/src/utils/tauriCommands/vault.ts
@@ -15,8 +15,12 @@ export interface CoreVault {
   created_at: string;
   last_synced_at?: string | null;
   file_count: number;
+  write_state: CoreVaultWriteState;
+  write_state_reason?: string | null;
 }
 
+export type CoreVaultWriteState = 'writable' | 'read_only' | 'unavailable';
+
 export type CoreVaultFileStatus = 'ok' | 'skipped' | 'failed';
 
 export interface CoreVaultFile {
@@ -98,6 +102,30 @@ export async function openhumanVaultFiles(
   });
 }
 
+export async function openhumanVaultWriteMarkdown(params: {
+  vaultId: string;
+  relPath: string;
+  content: string;
+  overwrite?: boolean;
+  approved: boolean;
+}): Promise<
+  CommandResponse<{ vault_id: string; rel_path: string; bytes_written: number; created: boolean }>
+> {
+  ensureTauri();
+  return await callCoreRpc<
+    CommandResponse<{ vault_id: string; rel_path: string; bytes_written: number; created: boolean }>
+  >({
+    method: 'openhuman.vault_write_markdown',
+    params: {
+      vault_id: params.vaultId,
+      rel_path: params.relPath,
+      content: params.content,
+      overwrite: params.overwrite ?? false,
+      approved: params.approved,
+    },
+  });
+}
+
 export async function openhumanVaultRemove(
   vaultId: string,
   purgeMemory: boolean
diff --git a/docs/TEST-COVERAGE-MATRIX.md b/docs/TEST-COVERAGE-MATRIX.md
index ea5066dbf..c3562812b 100644
--- a/docs/TEST-COVERAGE-MATRIX.md
+++ b/docs/TEST-COVERAGE-MATRIX.md
@@ -422,6 +422,7 @@ Canonical mapping of every product feature to its test source(s). Drives gap-fil
 | 11.1.6 | SearXNG MCP search         | RU    | `src/openhuman/integrations/searxng.rs`, `src/openhuman/mcp_server/tools.rs`, `src/openhuman/tools/schemas.rs`      | ✅     | Self-hosted search config, normalized results, MCP argument validation, and mocked HTTP execution |
 | 11.1.7 | Bundled prompt resources   | RU    | `src/openhuman/mcp_server/resources.rs`, `src/openhuman/mcp_server/protocol.rs`                                     | ✅     | `resources/list` catalog + `resources/read` happy path, -32002 unknown URI, -32602 missing param, catalog-mirrors-BUILTINS parity test |
 | 11.1.8 | Resource templates list    | RU    | `src/openhuman/mcp_server/resources.rs`, `src/openhuman/mcp_server/protocol.rs`                                     | ✅     | `resources/templates/list` returns `{resourceTemplates: []}` (static catalog), tolerates unknown/cursor params |
+| 11.1.9 | Vault Markdown Writes      | RU/VU | `src/openhuman/vault/tests.rs`, `app/src/components/intelligence/VaultPanel.test.tsx`, `app/src/utils/tauriCommands/vault.test.ts` | ✅     | User-added vaults expose writable/read-only/unavailable state; approved markdown writes reject missing approval, path escapes, and non-markdown targets |
 
 ### 11.2 Insights Dashboard
 
diff --git a/gitbooks/developing/architecture/frontend.md b/gitbooks/developing/architecture/frontend.md
index a90604f18..6fad712c2 100644
--- a/gitbooks/developing/architecture/frontend.md
+++ b/gitbooks/developing/architecture/frontend.md
@@ -587,6 +587,16 @@ const result = await callCoreRpc<MyType>({
 
 Implementation: `invoke('core_rpc_relay', { request: { method, params, serviceManaged } })` → `app/src-tauri/src/commands/core_relay.rs` → HTTP client in `app/src-tauri/src/core_rpc.rs`.
 
+### Knowledge Vault Write State
+
+`VaultPanel` in `app/src/components/intelligence/` renders user-added knowledge vaults from the core `vault.*` controller surface. Each vault row must show the core-provided `write_state`:
+
+- `writable` means approved markdown/wiki writes can be saved under the vault root.
+- `read_only` means the folder exists but local permissions report it as read-only.
+- `unavailable` means the folder is missing, no longer a directory, or cannot be inspected on this device.
+
+The UI should not infer writability from the path string alone. It maps the core-provided `write_state_reason` code through i18n so unsupported write states are visible instead of failing silently. Approved artifact creation uses `openhuman.vault_write_markdown`; callers must pass `approved: true`, a relative `.md` or `.markdown` path, and content. The core rejects absolute paths, `..` traversal, non-markdown files, symlink escapes, and updates without `overwrite: true`.
+
 ### Service integration with providers
 
 #### SocketProvider
diff --git a/src/openhuman/about_app/catalog_data.rs b/src/openhuman/about_app/catalog_data.rs
index fdd115b4b..30ebe6762 100644
--- a/src/openhuman/about_app/catalog_data.rs
+++ b/src/openhuman/about_app/catalog_data.rs
@@ -310,6 +310,16 @@ pub(super) const CAPABILITIES: &[Capability] = &[
         status: CapabilityStatus::Beta,
         privacy: LOCAL_RAW,
     },
+    Capability {
+        id: "intelligence.vault_markdown_writes",
+        name: "Vault Markdown Writes",
+        domain: "intelligence",
+        category: CapabilityCategory::Intelligence,
+        description: "Show whether a user-added local vault is writable, and write explicitly approved markdown/wiki artifacts back into that vault without leaving the device.",
+        how_to: "Intelligence > Memory > Knowledge vaults",
+        status: CapabilityStatus::Beta,
+        privacy: LOCAL_RAW,
+    },
     Capability {
         id: "intelligence.embedding_provider_config",
         name: "Configure Embedding Provider",
diff --git a/src/openhuman/about_app/catalog_tests.rs b/src/openhuman/about_app/catalog_tests.rs
index a385f7994..5cc917431 100644
--- a/src/openhuman/about_app/catalog_tests.rs
+++ b/src/openhuman/about_app/catalog_tests.rs
@@ -103,6 +103,7 @@ fn catalog_includes_additional_user_facing_surfaces() {
         "intelligence.mcp_server",
         "intelligence.searxng_search",
         "intelligence.tool_registry",
+        "intelligence.vault_markdown_writes",
         "intelligence.embedding_provider_config",
         "intelligence.embedding_provider_test",
         "conversation.subagent_mascots",
diff --git a/src/openhuman/tools/impl/filesystem/mod.rs b/src/openhuman/tools/impl/filesystem/mod.rs
index aa8e607a5..3fe9ec862 100644
--- a/src/openhuman/tools/impl/filesystem/mod.rs
+++ b/src/openhuman/tools/impl/filesystem/mod.rs
@@ -11,6 +11,7 @@ mod read_diff;
 mod run_linter;
 mod run_tests;
 mod update_memory_md;
+mod vault_write_markdown;
 
 pub use apply_patch::ApplyPatchTool;
 pub use csv_export::CsvExportTool;
@@ -25,3 +26,4 @@ pub use read_diff::ReadDiffTool;
 pub use run_linter::RunLinterTool;
 pub use run_tests::RunTestsTool;
 pub use update_memory_md::UpdateMemoryMdTool;
+pub use vault_write_markdown::VaultWriteMarkdownTool;
diff --git a/src/openhuman/tools/impl/filesystem/vault_write_markdown.rs b/src/openhuman/tools/impl/filesystem/vault_write_markdown.rs
new file mode 100644
index 000000000..b31adbcb6
--- /dev/null
+++ b/src/openhuman/tools/impl/filesystem/vault_write_markdown.rs
@@ -0,0 +1,177 @@
+//! Tool: vault_write_markdown — approved markdown/wiki writes into user vaults.
+
+use std::sync::Arc;
+
+use async_trait::async_trait;
+use serde_json::json;
+
+use crate::openhuman::config::Config;
+use crate::openhuman::security::{CommandClass, GateDecision, SecurityPolicy};
+use crate::openhuman::tools::traits::{PermissionLevel, Tool, ToolResult};
+
+pub struct VaultWriteMarkdownTool {
+    config: Arc<Config>,
+    security: Arc<SecurityPolicy>,
+}
+
+impl VaultWriteMarkdownTool {
+    pub fn new(config: Arc<Config>, security: Arc<SecurityPolicy>) -> Self {
+        Self { config, security }
+    }
+}
+
+#[async_trait]
+impl Tool for VaultWriteMarkdownTool {
+    fn name(&self) -> &str {
+        "vault_write_markdown"
+    }
+
+    fn description(&self) -> &str {
+        "Create or update an approved .md/.markdown wiki note inside a registered knowledge vault. \
+         Use only after the user has approved writing generated content into that vault."
+    }
+
+    fn parameters_schema(&self) -> serde_json::Value {
+        json!({
+            "type": "object",
+            "required": ["vault_id", "rel_path", "content"],
+            "properties": {
+                "vault_id": {
+                    "type": "string",
+                    "description": "Identifier of the registered vault to write into."
+                },
+                "rel_path": {
+                    "type": "string",
+                    "description": "Relative path under the vault root. Must end with .md or .markdown."
+                },
+                "content": {
+                    "type": "string",
+                    "description": "Markdown content to write."
+                },
+                "overwrite": {
+                    "type": "boolean",
+                    "description": "Set true to update an existing markdown file."
+                }
+            }
+        })
+    }
+
+    fn permission_level(&self) -> PermissionLevel {
+        PermissionLevel::Write
+    }
+
+    fn external_effect_with_args(&self, _args: &serde_json::Value) -> bool {
+        self.security.gate_decision(CommandClass::Write) == GateDecision::Prompt
+    }
+
+    async fn execute(&self, args: serde_json::Value) -> anyhow::Result<ToolResult> {
+        if !self.security.can_act() {
+            return Ok(ToolResult::error(
+                "[policy-blocked] Action blocked: autonomy is read-only",
+            ));
+        }
+        if self.security.is_rate_limited() {
+            return Ok(ToolResult::error(
+                "Rate limit exceeded: too many actions in the last hour",
+            ));
+        }
+
+        let vault_id = args
+            .get("vault_id")
+            .and_then(|value| value.as_str())
+            .ok_or_else(|| anyhow::anyhow!("Missing 'vault_id' parameter"))?;
+        let rel_path = args
+            .get("rel_path")
+            .and_then(|value| value.as_str())
+            .ok_or_else(|| anyhow::anyhow!("Missing 'rel_path' parameter"))?;
+        let content = args
+            .get("content")
+            .and_then(|value| value.as_str())
+            .ok_or_else(|| anyhow::anyhow!("Missing 'content' parameter"))?;
+        let overwrite = args
+            .get("overwrite")
+            .and_then(|value| value.as_bool())
+            .unwrap_or(false);
+
+        if !self.security.record_action() {
+            return Ok(ToolResult::error(
+                "Rate limit exceeded: action budget exhausted",
+            ));
+        }
+
+        tracing::debug!(
+            vault_id = %vault_id,
+            rel_path = %rel_path,
+            overwrite,
+            content_bytes = content.len(),
+            "[vault_write_markdown] execute"
+        );
+        match crate::openhuman::vault::ops::vault_write_markdown(
+            &self.config,
+            vault_id,
+            rel_path,
+            content,
+            overwrite,
+            true,
+        )
+        .await
+        {
+            Ok(outcome) => Ok(ToolResult::json(json!(outcome.value))),
+            Err(err) => Ok(ToolResult::error(err)),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::openhuman::security::AutonomyLevel;
+
+    fn security(workspace: std::path::PathBuf, autonomy: AutonomyLevel) -> Arc<SecurityPolicy> {
+        Arc::new(SecurityPolicy {
+            autonomy,
+            workspace_dir: workspace,
+            ..SecurityPolicy::default()
+        })
+    }
+
+    #[test]
+    fn vault_write_markdown_tool_schema_requires_core_fields() {
+        let dir = tempfile::tempdir().unwrap();
+        let config = Arc::new(Config::default());
+        let tool = VaultWriteMarkdownTool::new(
+            config,
+            security(dir.path().to_path_buf(), AutonomyLevel::Supervised),
+        );
+
+        assert_eq!(tool.name(), "vault_write_markdown");
+        assert_eq!(tool.permission_level(), PermissionLevel::Write);
+        assert!(tool.external_effect_with_args(&json!({})));
+        let schema = tool.parameters_schema();
+        let required = schema["required"].as_array().unwrap();
+        assert!(required.iter().any(|value| value == "vault_id"));
+        assert!(required.iter().any(|value| value == "rel_path"));
+        assert!(required.iter().any(|value| value == "content"));
+    }
+
+    #[tokio::test]
+    async fn vault_write_markdown_tool_blocks_read_only_autonomy() {
+        let dir = tempfile::tempdir().unwrap();
+        let config = Arc::new(Config::default());
+        let tool = VaultWriteMarkdownTool::new(
+            config,
+            security(dir.path().to_path_buf(), AutonomyLevel::ReadOnly),
+        );
+
+        let result = tool
+            .execute(json!({
+                "vault_id": "v-1",
+                "rel_path": "wiki/a.md",
+                "content": "# A"
+            }))
+            .await
+            .unwrap();
+        assert!(result.is_error);
+        assert!(result.text().contains("read-only"));
+    }
+}
diff --git a/src/openhuman/tools/ops.rs b/src/openhuman/tools/ops.rs
index cc6d6400f..3a5fbeb8c 100644
--- a/src/openhuman/tools/ops.rs
+++ b/src/openhuman/tools/ops.rs
@@ -133,6 +133,10 @@ pub fn all_tools_with_runtime(
         shell,
         Box::new(FileReadTool::new(security.clone())),
         Box::new(FileWriteTool::new(security.clone())),
+        Box::new(VaultWriteMarkdownTool::new(
+            config.clone(),
+            security.clone(),
+        )),
         // Coding-harness baseline tools (issue #1205): file navigation
         // + atomic editing primitives. Use these instead of falling
         // through to `shell` for grep/find/sed work.
diff --git a/src/openhuman/tools/ops_tests.rs b/src/openhuman/tools/ops_tests.rs
index 30e963a0a..d4a79e91a 100644
--- a/src/openhuman/tools/ops_tests.rs
+++ b/src/openhuman/tools/ops_tests.rs
@@ -177,6 +177,43 @@ fn all_tools_includes_spawn_parallel_agents() {
     );
 }
 
+#[test]
+fn all_tools_includes_vault_write_markdown() {
+    let tmp = TempDir::new().unwrap();
+    let security = Arc::new(SecurityPolicy::default());
+    let mem_cfg = MemoryConfig {
+        backend: "markdown".into(),
+        ..MemoryConfig::default()
+    };
+    let mem: Arc<dyn Memory> =
+        Arc::from(crate::openhuman::memory_store::create_memory(&mem_cfg, tmp.path()).unwrap());
+    let browser = BrowserConfig {
+        enabled: false,
+        allowed_domains: vec![],
+        session_name: None,
+        ..BrowserConfig::default()
+    };
+    let http = crate::openhuman::config::HttpRequestConfig::default();
+    let cfg = test_config(&tmp);
+
+    let tools = all_tools(
+        Arc::new(cfg.clone()),
+        &security,
+        AuditLogger::disabled(),
+        mem,
+        &browser,
+        &http,
+        tmp.path(),
+        &HashMap::new(),
+        &cfg,
+    );
+    let names: Vec<&str> = tools.iter().map(|t| t.name()).collect();
+    assert!(
+        names.contains(&"vault_write_markdown"),
+        "vault_write_markdown must be registered so agents can write approved markdown into user vaults; got: {names:?}"
+    );
+}
+
 #[test]
 fn all_tools_always_registers_curl() {
     // Regression guard: `curl` is always registered (gated only by
@@ -382,6 +419,7 @@ fn all_tools_default_registry_contains_expected_baseline_surface() {
             "shell",
             "file_read",
             "file_write",
+            "vault_write_markdown",
             "grep",
             "glob",
             "list",
diff --git a/src/openhuman/tools/user_filter.rs b/src/openhuman/tools/user_filter.rs
index 806ac7317..8b1b2d646 100644
--- a/src/openhuman/tools/user_filter.rs
+++ b/src/openhuman/tools/user_filter.rs
@@ -9,7 +9,10 @@ const TOOL_ID_TO_RUST_NAMES: &[(&str, &[&str])] = &[
     ("install_tool", &["install_tool"]),
     ("git_operations", &["git_operations"]),
     ("file_read", &["file_read", "read_diff", "csv_export"]),
-    ("file_write", &["file_write", "update_memory_md"]),
+    (
+        "file_write",
+        &["file_write", "update_memory_md", "vault_write_markdown"],
+    ),
     ("screenshot", &["screenshot"]),
     ("image_info", &["image_info"]),
     ("browser_open", &["browser_open"]),
diff --git a/src/openhuman/vault/mod.rs b/src/openhuman/vault/mod.rs
index d1bb6b44d..3a5bee096 100644
--- a/src/openhuman/vault/mod.rs
+++ b/src/openhuman/vault/mod.rs
@@ -18,6 +18,7 @@ pub use schemas::{
 };
 pub use types::{
     Vault, VaultFile, VaultFileStatus, VaultSyncReport, VaultSyncState, VaultSyncStatus,
+    VaultWriteMarkdownReport, VaultWriteState,
 };
 
 #[cfg(test)]
diff --git a/src/openhuman/vault/ops.rs b/src/openhuman/vault/ops.rs
index 3975ebf0e..a6b495cbc 100644
--- a/src/openhuman/vault/ops.rs
+++ b/src/openhuman/vault/ops.rs
@@ -3,6 +3,7 @@
 use chrono::Utc;
 use futures::FutureExt;
 use sha2::{Digest, Sha256};
+use std::path::{Component, Path, PathBuf};
 use uuid::Uuid;
 
 use crate::openhuman::config::Config;
@@ -14,7 +15,9 @@ use crate::rpc::RpcOutcome;
 use super::state;
 use super::store;
 use super::sync;
-use super::types::{Vault, VaultFile, VaultSyncState, VaultSyncStatus};
+use super::types::{
+    Vault, VaultFile, VaultSyncState, VaultSyncStatus, VaultWriteMarkdownReport, VaultWriteState,
+};
 
 /// Derive a stable memory namespace for a vault without embedding the raw UUID.
 ///
@@ -63,13 +66,15 @@ pub async fn vault_create(
         exclude_globs.len(),
     );
     let namespace = vault_namespace_for_id(&id);
+    let canonical_root = root
+        .canonicalize()
+        .map(|p| p.to_string_lossy().to_string())
+        .unwrap_or_else(|_| trimmed_root.to_string());
+    let (write_state, write_state_reason) = store::vault_write_state_for_root_path(&canonical_root);
     let vault = Vault {
         id: id.clone(),
         name: trimmed_name.to_string(),
-        root_path: root
-            .canonicalize()
-            .map(|p| p.to_string_lossy().to_string())
-            .unwrap_or_else(|_| trimmed_root.to_string()),
+        root_path: canonical_root,
         host_os: Some(store::current_host_os().to_string()),
         namespace,
         include_globs,
@@ -77,6 +82,8 @@ pub async fn vault_create(
         created_at: Utc::now(),
         last_synced_at: None,
         file_count: 0,
+        write_state,
+        write_state_reason,
     };
 
     store::insert_vault(config, &vault).map_err(|e| e.to_string())?;
@@ -104,6 +111,81 @@ pub async fn vault_get(config: &Config, id: &str) -> Result<RpcOutcome<Vault>, S
     Ok(RpcOutcome::single_log(vault, "vault loaded"))
 }
 
+/// Write an explicitly approved markdown/wiki artifact into a registered vault.
+pub async fn vault_write_markdown(
+    config: &Config,
+    id: &str,
+    rel_path: &str,
+    content: &str,
+    overwrite: bool,
+    approved: bool,
+) -> Result<RpcOutcome<VaultWriteMarkdownReport>, String> {
+    let id = id.trim();
+    if id.is_empty() {
+        return Err("vault_id must not be empty".to_string());
+    }
+    if !approved {
+        log::debug!("[vault] write_markdown: rejected missing approval id={id}");
+        return Err("vault markdown writes require explicit user approval".to_string());
+    }
+
+    let vault = store::get_vault(config, id)
+        .map_err(|e| e.to_string())?
+        .ok_or_else(|| format!("vault not found: {id}"))?;
+    let (write_state, write_reason) = store::vault_write_state_for_root_path(&vault.root_path);
+    if write_state != VaultWriteState::Writable {
+        log::debug!(
+            "[vault] write_markdown: rejected non-writable id={id} state={write_state:?} reason={write_reason:?}"
+        );
+        return Err(store::vault_write_state_reason_message(write_reason.as_deref()).to_string());
+    }
+
+    let rel = validate_markdown_rel_path(rel_path)?;
+    let bytes = content.as_bytes().len() as u64;
+    let root = std::fs::canonicalize(&vault.root_path)
+        .map_err(|err| format!("failed to resolve vault folder: {err}"))?;
+    ensure_existing_ancestors_stay_in_root(&root, &rel)?;
+    let target = root.join(&rel);
+    let parent = target
+        .parent()
+        .ok_or_else(|| "target path has no parent directory".to_string())?;
+    std::fs::create_dir_all(parent)
+        .map_err(|err| format!("failed to create vault note directory: {err}"))?;
+    let parent_canon = std::fs::canonicalize(parent)
+        .map_err(|err| format!("failed to resolve vault note directory: {err}"))?;
+    if !parent_canon.starts_with(&root) {
+        return Err("vault note path resolves outside the vault folder".to_string());
+    }
+    if let Ok(meta) = std::fs::symlink_metadata(&target) {
+        if meta.file_type().is_symlink() {
+            return Err("refusing to write through a symlink inside the vault".to_string());
+        }
+    }
+    let created = !target.exists();
+    if !created && !overwrite {
+        return Err(
+            "vault markdown file already exists; set overwrite=true to update it".to_string(),
+        );
+    }
+
+    log::debug!(
+        "[vault] write_markdown: writing id={id} rel_path={} bytes={bytes} overwrite={overwrite} created={created}",
+        rel.display()
+    );
+    std::fs::write(&target, content)
+        .map_err(|err| format!("failed to write vault markdown file: {err}"))?;
+
+    Ok(RpcOutcome::single_log(
+        VaultWriteMarkdownReport {
+            vault_id: id.to_string(),
+            rel_path: rel.to_string_lossy().replace('\\', "/"),
+            bytes_written: bytes,
+            created,
+        },
+        format!("vault markdown written: {id}"),
+    ))
+}
+
 pub async fn vault_files(config: &Config, id: &str) -> Result<RpcOutcome<Vec<VaultFile>>, String> {
     let id = id.trim();
     if id.is_empty() {
@@ -117,6 +199,82 @@ pub async fn vault_files(config: &Config, id: &str) -> Result<RpcOutcome<Vec<Vau
     Ok(RpcOutcome::single_log(files, "vault files listed"))
 }
 
+fn validate_markdown_rel_path(raw: &str) -> Result<PathBuf, String> {
+    let trimmed = raw.trim();
+    if trimmed.is_empty() {
+        return Err("rel_path must not be empty".to_string());
+    }
+    let path = Path::new(trimmed);
+    if path.is_absolute() {
+        return Err("rel_path must be relative to the vault folder".to_string());
+    }
+
+    let mut clean = PathBuf::new();
+    for component in path.components() {
+        match component {
+            Component::Normal(part) => clean.push(part),
+            Component::CurDir => {}
+            Component::ParentDir => {
+                return Err("rel_path must not contain '..' segments".to_string());
+            }
+            Component::RootDir | Component::Prefix(_) => {
+                return Err("rel_path must stay inside the vault folder".to_string());
+            }
+        }
+    }
+    if clean.as_os_str().is_empty() {
+        return Err("rel_path must name a markdown file".to_string());
+    }
+    let ext = clean
+        .extension()
+        .and_then(|value| value.to_str())
+        .unwrap_or_default();
+    if !matches!(ext.to_ascii_lowercase().as_str(), "md" | "markdown") {
+        return Err("rel_path must end with .md or .markdown".to_string());
+    }
+    Ok(clean)
+}
+
+fn ensure_existing_ancestors_stay_in_root(root: &Path, rel_path: &Path) -> Result<(), String> {
+    let Some(parent) = rel_path.parent() else {
+        return Ok(());
+    };
+
+    let mut current = root.to_path_buf();
+    for component in parent.components() {
+        let Component::Normal(part) = component else {
+            continue;
+        };
+        let next = current.join(part);
+        match std::fs::symlink_metadata(&next) {
+            Ok(meta) if meta.file_type().is_symlink() => {
+                let resolved = std::fs::canonicalize(&next)
+                    .map_err(|err| format!("failed to resolve vault note directory: {err}"))?;
+                if !resolved.starts_with(root) {
+                    return Err(
+                        "vault note directory resolves outside the vault folder".to_string()
+                    );
+                }
+                current = resolved;
+            }
+            Ok(meta) if meta.is_dir() => {
+                current = next;
+            }
+            Ok(_) => {
+                return Err("vault note parent path is not a directory".to_string());
+            }
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                break;
+            }
+            Err(err) => {
+                return Err(format!("failed to inspect vault note directory: {err}"));
+            }
+        }
+    }
+
+    Ok(())
+}
+
 pub async fn vault_remove(
     config: &Config,
     id: &str,
diff --git a/src/openhuman/vault/schemas.rs b/src/openhuman/vault/schemas.rs
index b1b683e59..4fec3ac5a 100644
--- a/src/openhuman/vault/schemas.rs
+++ b/src/openhuman/vault/schemas.rs
@@ -21,6 +21,7 @@ pub fn all_controller_schemas() -> Vec<ControllerSchema> {
         schemas("list"),
         schemas("get"),
         schemas("files"),
+        schemas("write_markdown"),
         schemas("remove"),
         schemas("sync"),
         schemas("sync_status"),
@@ -45,6 +46,10 @@ pub fn all_registered_controllers() -> Vec<RegisteredController> {
             schema: schemas("files"),
             handler: handle_files,
         },
+        RegisteredController {
+            schema: schemas("write_markdown"),
+            handler: handle_write_markdown,
+        },
         RegisteredController {
             schema: schemas("remove"),
             handler: handle_remove,
@@ -139,6 +144,44 @@ pub fn schemas(function: &str) -> ControllerSchema {
                 required: true,
             }],
         },
+        "write_markdown" => ControllerSchema {
+            namespace: "vault",
+            function: "write_markdown",
+            description: "Write an explicitly approved markdown/wiki file inside a writable vault.",
+            inputs: vec![
+                vault_id_input("Identifier of the vault to write into."),
+                FieldSchema {
+                    name: "rel_path",
+                    ty: TypeSchema::String,
+                    comment: "Relative .md/.markdown path inside the vault.",
+                    required: true,
+                },
+                FieldSchema {
+                    name: "content",
+                    ty: TypeSchema::String,
+                    comment: "Markdown content to write.",
+                    required: true,
+                },
+                FieldSchema {
+                    name: "overwrite",
+                    ty: TypeSchema::Option(Box::new(TypeSchema::Bool)),
+                    comment: "When true, update an existing markdown file.",
+                    required: false,
+                },
+                FieldSchema {
+                    name: "approved",
+                    ty: TypeSchema::Bool,
+                    comment: "Must be true after explicit user approval for arbitrary vault writes.",
+                    required: true,
+                },
+            ],
+            outputs: vec![FieldSchema {
+                name: "report",
+                ty: TypeSchema::Ref("VaultWriteMarkdownReport"),
+                comment: "Write result with relative path and byte count.",
+                required: true,
+            }],
+        },
         "remove" => ControllerSchema {
             namespace: "vault",
             function: "remove",
@@ -283,6 +326,23 @@ fn handle_files(params: Map<String, Value>) -> ControllerFuture {
     })
 }
 
+fn handle_write_markdown(params: Map<String, Value>) -> ControllerFuture {
+    Box::pin(async move {
+        let config = config_rpc::load_config_with_timeout().await?;
+        let vault_id = read_required::<String>(&params, "vault_id")?;
+        let rel_path = read_required::<String>(&params, "rel_path")?;
+        let content = read_required::<String>(&params, "content")?;
+        let overwrite = read_optional::<bool>(&params, "overwrite")?.unwrap_or(false);
+        let approved = read_required::<bool>(&params, "approved")?;
+        to_json(
+            crate::openhuman::vault::ops::vault_write_markdown(
+                &config, &vault_id, &rel_path, &content, overwrite, approved,
+            )
+            .await?,
+        )
+    })
+}
+
 fn handle_remove(params: Map<String, Value>) -> ControllerFuture {
     Box::pin(async move {
         let config = config_rpc::load_config_with_timeout().await?;
diff --git a/src/openhuman/vault/store.rs b/src/openhuman/vault/store.rs
index b37316089..92bfc0816 100644
--- a/src/openhuman/vault/store.rs
+++ b/src/openhuman/vault/store.rs
@@ -8,10 +8,16 @@ use rusqlite::{params, Connection, OptionalExtension};
 
 use crate::openhuman::config::Config;
 
-use super::types::{Vault, VaultFile, VaultFileStatus};
+use super::types::{Vault, VaultFile, VaultFileStatus, VaultWriteState};
 
 static MIGRATED_VAULT_DBS: OnceLock<Mutex<HashSet<PathBuf>>> = OnceLock::new();
 
+pub(crate) const VAULT_WRITE_REASON_EMPTY_PATH: &str = "empty_path";
+pub(crate) const VAULT_WRITE_REASON_UNAVAILABLE: &str = "unavailable";
+pub(crate) const VAULT_WRITE_REASON_NOT_DIRECTORY: &str = "not_directory";
+pub(crate) const VAULT_WRITE_REASON_READ_ONLY: &str = "read_only";
+pub(crate) const VAULT_WRITE_REASON_WRITABLE: &str = "writable";
+
 pub(crate) fn with_connection<T>(
     config: &Config,
     f: impl FnOnce(&Connection) -> Result<T>,
@@ -225,10 +231,12 @@ fn row_to_vault(row: &rusqlite::Row<'_>) -> rusqlite::Result<Vault> {
     let created_raw: String = row.get(7)?;
     let last_raw: Option<String> = row.get(8)?;
     let file_count: i64 = row.get(9)?;
+    let root_path: String = row.get(2)?;
+    let (write_state, write_state_reason) = vault_write_state_for_root_path(&root_path);
     Ok(Vault {
         id: row.get(0)?,
         name: row.get(1)?,
-        root_path: row.get(2)?,
+        root_path,
         host_os: row.get(3)?,
         namespace: row.get(4)?,
         include_globs: serde_json::from_str(&include_raw).unwrap_or_default(),
@@ -236,6 +244,8 @@ fn row_to_vault(row: &rusqlite::Row<'_>) -> rusqlite::Result<Vault> {
         created_at: parse_dt(&created_raw),
         last_synced_at: last_raw.as_deref().map(parse_dt),
         file_count: file_count.max(0) as u64,
+        write_state,
+        write_state_reason,
     })
 }
 
@@ -282,6 +292,61 @@ pub(crate) fn current_host_os() -> &'static str {
     std::env::consts::OS
 }
 
+pub(crate) fn vault_write_state_for_root_path(
+    root_path: &str,
+) -> (VaultWriteState, Option<String>) {
+    let trimmed = root_path.trim();
+    if trimmed.is_empty() {
+        return (
+            VaultWriteState::Unavailable,
+            Some(VAULT_WRITE_REASON_EMPTY_PATH.to_string()),
+        );
+    }
+
+    let path = std::path::Path::new(trimmed);
+    let metadata = match std::fs::metadata(path) {
+        Ok(metadata) => metadata,
+        Err(_) => {
+            return (
+                VaultWriteState::Unavailable,
+                Some(VAULT_WRITE_REASON_UNAVAILABLE.to_string()),
+            )
+        }
+    };
+
+    if !metadata.is_dir() {
+        return (
+            VaultWriteState::Unavailable,
+            Some(VAULT_WRITE_REASON_NOT_DIRECTORY.to_string()),
+        );
+    }
+
+    if metadata.permissions().readonly() {
+        return (
+            VaultWriteState::ReadOnly,
+            Some(VAULT_WRITE_REASON_READ_ONLY.to_string()),
+        );
+    }
+
+    (
+        VaultWriteState::Writable,
+        Some(VAULT_WRITE_REASON_WRITABLE.to_string()),
+    )
+}
+
+pub(crate) fn vault_write_state_reason_message(reason_code: Option<&str>) -> &'static str {
+    match reason_code {
+        Some(VAULT_WRITE_REASON_EMPTY_PATH) => "Vault folder path is empty.",
+        Some(VAULT_WRITE_REASON_UNAVAILABLE) => "Vault folder is not available on this device.",
+        Some(VAULT_WRITE_REASON_NOT_DIRECTORY) => "Vault path is not a directory.",
+        Some(VAULT_WRITE_REASON_READ_ONLY) => "Vault folder is read-only on this device.",
+        Some(VAULT_WRITE_REASON_WRITABLE) => {
+            "Approved markdown/wiki writes can be saved in this vault."
+        }
+        _ => "Vault write state is unknown.",
+    }
+}
+
 pub(crate) fn path_looks_compatible_with_host_os(raw_path: &str, host_os: &str) -> bool {
     let path = raw_path.trim();
     if path.is_empty() {
diff --git a/src/openhuman/vault/sync.rs b/src/openhuman/vault/sync.rs
index a234db83c..f91c366f4 100644
--- a/src/openhuman/vault/sync.rs
+++ b/src/openhuman/vault/sync.rs
@@ -702,6 +702,7 @@ mod sync_tests {
     use super::*;
     use crate::openhuman::memory_store::chunks::store::{count_chunks, is_source_ingested};
     use crate::openhuman::vault::ops;
+    use crate::openhuman::vault::VaultWriteState;
     use tempfile::TempDir;
 
     /// Test-config pattern mirrors `memory::sync_pipeline_e2e_test::test_config`:
@@ -730,6 +731,8 @@ mod sync_tests {
             created_at: Utc::now(),
             last_synced_at: None,
             file_count: 0,
+            write_state: VaultWriteState::Writable,
+            write_state_reason: None,
         }
     }
 
diff --git a/src/openhuman/vault/tests.rs b/src/openhuman/vault/tests.rs
index 972ddc86d..051702e40 100644
--- a/src/openhuman/vault/tests.rs
+++ b/src/openhuman/vault/tests.rs
@@ -10,7 +10,9 @@ use super::ops;
 use super::state;
 use super::store;
 use super::sync::supported_extension;
-use super::types::{Vault, VaultFile, VaultFileStatus, VaultSyncState, VaultSyncStatus};
+use super::types::{
+    Vault, VaultFile, VaultFileStatus, VaultSyncState, VaultSyncStatus, VaultWriteState,
+};
 
 fn make_config(tmp: &TempDir) -> Config {
     let mut config = Config::default();
@@ -30,6 +32,8 @@ fn sample_vault(root: PathBuf) -> Vault {
         created_at: chrono::Utc::now(),
         last_synced_at: None,
         file_count: 0,
+        write_state: VaultWriteState::Writable,
+        write_state_reason: None,
     }
 }
 
@@ -99,6 +103,31 @@ fn store_stamps_new_vaults_with_current_host_os() {
     let listed = store::list_vaults(&config).unwrap();
     assert_eq!(listed.len(), 1);
     assert_eq!(listed[0].host_os.as_deref(), Some(std::env::consts::OS));
+    assert_eq!(listed[0].write_state, VaultWriteState::Writable);
+    assert_eq!(
+        listed[0].write_state_reason.as_deref(),
+        Some(store::VAULT_WRITE_REASON_WRITABLE)
+    );
+}
+
+#[test]
+fn store_marks_missing_vault_folder_unavailable_instead_of_hiding_it() {
+    let tmp = TempDir::new().unwrap();
+    let config = make_config(&tmp);
+    let vault_root = tmp.path().join("vault-root");
+    std::fs::create_dir_all(&vault_root).unwrap();
+    let vault = sample_vault(vault_root.clone());
+
+    store::insert_vault(&config, &vault).unwrap();
+    std::fs::remove_dir_all(&vault_root).unwrap();
+
+    let listed = store::list_vaults(&config).unwrap();
+    assert_eq!(listed.len(), 1);
+    assert_eq!(listed[0].write_state, VaultWriteState::Unavailable);
+    assert_eq!(
+        listed[0].write_state_reason.as_deref(),
+        Some(store::VAULT_WRITE_REASON_UNAVAILABLE)
+    );
 }
 
 #[test]
@@ -342,6 +371,11 @@ async fn vault_create_returns_current_host_os() {
     .unwrap();
 
     assert_eq!(outcome.value.host_os.as_deref(), Some(std::env::consts::OS));
+    assert_eq!(outcome.value.write_state, VaultWriteState::Writable);
+    assert_eq!(
+        outcome.value.write_state_reason.as_deref(),
+        Some(store::VAULT_WRITE_REASON_WRITABLE)
+    );
 }
 
 #[tokio::test]
@@ -390,6 +424,160 @@ async fn vault_sync_status_returns_idle_for_unknown_vault() {
     assert_eq!(outcome.value.ingested, 0);
 }
 
+#[tokio::test]
+async fn vault_write_markdown_requires_explicit_approval() {
+    let tmp = TempDir::new().unwrap();
+    let config = make_config(&tmp);
+
+    let vault = ops::vault_create(
+        &config,
+        "Test",
+        tmp.path().to_str().unwrap(),
+        vec![],
+        vec![],
+    )
+    .await
+    .unwrap()
+    .value;
+
+    let err = ops::vault_write_markdown(
+        &config,
+        &vault.id,
+        "wiki/summary.md",
+        "# Summary\n",
+        false,
+        false,
+    )
+    .await
+    .unwrap_err();
+    assert!(err.contains("explicit user approval"));
+}
+
+#[tokio::test]
+async fn vault_write_markdown_creates_and_updates_relative_markdown() {
+    let tmp = TempDir::new().unwrap();
+    let config = make_config(&tmp);
+    let vault_root = tmp.path().join("vault-root");
+    std::fs::create_dir_all(&vault_root).unwrap();
+
+    let vault = ops::vault_create(
+        &config,
+        "Test",
+        vault_root.to_str().unwrap(),
+        vec![],
+        vec![],
+    )
+    .await
+    .unwrap()
+    .value;
+
+    let first = ops::vault_write_markdown(
+        &config,
+        &vault.id,
+        "wiki/summary.md",
+        "# Summary\n\nInitial.",
+        false,
+        true,
+    )
+    .await
+    .unwrap()
+    .value;
+    assert!(first.created);
+    assert_eq!(first.rel_path, "wiki/summary.md");
+    assert_eq!(first.bytes_written, "# Summary\n\nInitial.".len() as u64);
+    assert_eq!(
+        std::fs::read_to_string(vault_root.join("wiki/summary.md")).unwrap(),
+        "# Summary\n\nInitial."
+    );
+
+    let duplicate = ops::vault_write_markdown(
+        &config,
+        &vault.id,
+        "wiki/summary.md",
+        "# Summary\n\nUpdated.",
+        false,
+        true,
+    )
+    .await
+    .unwrap_err();
+    assert!(duplicate.contains("already exists"));
+
+    let updated = ops::vault_write_markdown(
+        &config,
+        &vault.id,
+        "wiki/summary.md",
+        "# Summary\n\nUpdated.",
+        true,
+        true,
+    )
+    .await
+    .unwrap()
+    .value;
+    assert!(!updated.created);
+    assert_eq!(
+        std::fs::read_to_string(vault_root.join("wiki/summary.md")).unwrap(),
+        "# Summary\n\nUpdated."
+    );
+}
+
+#[tokio::test]
+async fn vault_write_markdown_rejects_escape_paths_and_non_markdown() {
+    let tmp = TempDir::new().unwrap();
+    let config = make_config(&tmp);
+    let vault = ops::vault_create(
+        &config,
+        "Test",
+        tmp.path().to_str().unwrap(),
+        vec![],
+        vec![],
+    )
+    .await
+    .unwrap()
+    .value;
+
+    let traversal = ops::vault_write_markdown(&config, &vault.id, "../x.md", "x", false, true)
+        .await
+        .unwrap_err();
+    assert!(traversal.contains(".."));
+
+    let non_markdown =
+        ops::vault_write_markdown(&config, &vault.id, "notes/out.txt", "x", false, true)
+            .await
+            .unwrap_err();
+    assert!(non_markdown.contains(".md"));
+}
+
+#[cfg(unix)]
+#[tokio::test]
+async fn vault_write_markdown_rejects_symlink_escape() {
+    use std::os::unix::fs::symlink;
+
+    let tmp = TempDir::new().unwrap();
+    let config = make_config(&tmp);
+    let vault_root = tmp.path().join("vault-root");
+    let outside = tmp.path().join("outside");
+    std::fs::create_dir_all(&vault_root).unwrap();
+    std::fs::create_dir_all(&outside).unwrap();
+    symlink(&outside, vault_root.join("linked")).unwrap();
+
+    let vault = ops::vault_create(
+        &config,
+        "Test",
+        vault_root.to_str().unwrap(),
+        vec![],
+        vec![],
+    )
+    .await
+    .unwrap()
+    .value;
+
+    let err = ops::vault_write_markdown(&config, &vault.id, "linked/escape.md", "x", false, true)
+        .await
+        .unwrap_err();
+    assert!(err.contains("outside the vault"));
+    assert!(!outside.join("escape.md").exists());
+}
+
 #[tokio::test]
 async fn vault_sync_status_returns_state_when_present() {
     let id = "__ops_status_running__";
diff --git a/src/openhuman/vault/types.rs b/src/openhuman/vault/types.rs
index f73c25ce0..1e53de56c 100644
--- a/src/openhuman/vault/types.rs
+++ b/src/openhuman/vault/types.rs
@@ -59,6 +59,20 @@ pub struct Vault {
     pub created_at: DateTime<Utc>,
     pub last_synced_at: Option<DateTime<Utc>>,
     pub file_count: u64,
+    #[serde(default)]
+    pub write_state: VaultWriteState,
+    #[serde(default)]
+    pub write_state_reason: Option<String>,
+}
+
+/// Whether OpenHuman can write approved markdown artifacts back into a vault.
+#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum VaultWriteState {
+    Writable,
+    ReadOnly,
+    #[default]
+    Unavailable,
 }
 
 /// Per-file ledger entry used for dedup on re-sync.
@@ -113,3 +127,12 @@ pub struct VaultSyncReport {
     pub duration_ms: i64,
     pub errors: Vec<String>,
 }
+
+/// Result returned after writing an approved markdown/wiki artifact into a vault.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct VaultWriteMarkdownReport {
+    pub vault_id: String,
+    pub rel_path: String,
+    pub bytes_written: u64,
+    pub created: bool,
+}