diff --git a/App.tsx b/App.tsx
index a45808e0..93d8edfc 100644
--- a/App.tsx
+++ b/App.tsx
@@ -36,6 +36,7 @@ import { useAuthStore } from './src/stores/auth-store';
 import { useCalendarStore } from './src/stores/calendar-store';
 import { useContactsStore } from './src/stores/contacts-store';
 import { useEmailStore } from './src/stores/email-store';
+import { useHasCalendar, useHasContacts, useHasFiles } from './src/lib/capabilities';
 import { useSettingsStore } from './src/stores/settings-store';
 import { useLocaleStore } from './src/stores/locale-store';
 import { useNetworkStore } from './src/stores/network-store';
@@ -88,6 +89,10 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
   const mailboxes = useEmailStore((state) => state.mailboxes);
   const logout = useAuthStore((state) => state.logout);
   const inboxUnreadCount = mailboxes.find((mailbox) => mailbox.role === 'inbox')?.unreadEmails ?? 0;
+  const hasCalendar = useHasCalendar();
+  const hasContacts = useHasContacts();
+  const hasFiles = useHasFiles();
+  const disabledTabStyle = { opacity: 0.4 } as const;
 
   return (
     <View style={{ flex: 1, backgroundColor: c.background }}>
@@ -149,6 +154,13 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
         component={CalendarScreen}
         options={{
           tabBarIcon: ({ color, size }) => <Calendar size={size} color={color} />,
+          tabBarItemStyle: hasCalendar ? undefined : disabledTabStyle,
+          tabBarAccessibilityLabel: hasCalendar ? 'Calendar' : 'Calendar (unavailable)',
+        }}
+        listeners={{
+          tabPress: (e) => {
+            if (!hasCalendar) e.preventDefault();
+          },
         }}
       />
       <Tab.Screen
@@ -156,6 +168,13 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
         component={ContactsScreen}
         options={{
           tabBarIcon: ({ color, size }) => <BookUser size={size} color={color} />,
+          tabBarItemStyle: hasContacts ? undefined : disabledTabStyle,
+          tabBarAccessibilityLabel: hasContacts ? 'Contacts' : 'Contacts (unavailable)',
+        }}
+        listeners={{
+          tabPress: (e) => {
+            if (!hasContacts) e.preventDefault();
+          },
         }}
       />
       <Tab.Screen
@@ -163,6 +182,13 @@ function MainTabsNavigator({ navigation }: NativeStackScreenProps<RootStackParam
         component={FilesScreen}
         options={{
           tabBarIcon: ({ color, size }) => <HardDrive size={size} color={color} />,
+          tabBarItemStyle: hasFiles ? undefined : disabledTabStyle,
+          tabBarAccessibilityLabel: hasFiles ? 'Files' : 'Files (unavailable)',
+        }}
+        listeners={{
+          tabPress: (e) => {
+            if (!hasFiles) e.preventDefault();
+          },
         }}
       />
       <Tab.Screen
diff --git a/src/lib/capabilities.ts b/src/lib/capabilities.ts
new file mode 100644
index 00000000..6c9b103c
--- /dev/null
+++ b/src/lib/capabilities.ts
@@ -0,0 +1,35 @@
+import { CAPABILITIES } from '../api/types';
+import { useAuthStore } from '../stores/auth-store';
+
+// When the session is null (cold start, offline restore) we assume features
+// are available so they don't flicker off mid-restore. Once the live session
+// arrives, the real capability set takes over.
+function sessionHasCapability(capability: string): boolean {
+  const session = useAuthStore.getState().session;
+  if (!session) return true;
+  return capability in session.capabilities;
+}
+
+export function hasCalendarCapability(): boolean {
+  return sessionHasCapability(CAPABILITIES.CALENDARS);
+}
+
+export function hasContactsCapability(): boolean {
+  return sessionHasCapability(CAPABILITIES.CONTACTS);
+}
+
+export function hasFilesCapability(): boolean {
+  return sessionHasCapability(CAPABILITIES.FILES);
+}
+
+export function useHasCalendar(): boolean {
+  return useAuthStore((s) => (s.session ? CAPABILITIES.CALENDARS in s.session.capabilities : true));
+}
+
+export function useHasContacts(): boolean {
+  return useAuthStore((s) => (s.session ? CAPABILITIES.CONTACTS in s.session.capabilities : true));
+}
+
+export function useHasFiles(): boolean {
+  return useAuthStore((s) => (s.session ? CAPABILITIES.FILES in s.session.capabilities : true));
+}
diff --git a/src/screens/SettingsScreen.tsx b/src/screens/SettingsScreen.tsx
index 3d45777b..bcbe3f33 100644
--- a/src/screens/SettingsScreen.tsx
+++ b/src/screens/SettingsScreen.tsx
@@ -36,6 +36,7 @@ import { LanguageSettings } from '../components/settings/LanguageSettings';
 import { ComposingSettings } from '../components/settings/ComposingSettings';
 import { LayoutSettings } from '../components/settings/LayoutSettings';
 import { useLocaleStore } from '../stores/locale-store';
+import { useHasCalendar, useHasContacts, useHasFiles } from '../lib/capabilities';
 
 type Tab =
   | 'account' | 'language' | 'notifications'
@@ -155,6 +156,16 @@ export default function SettingsScreen({ onLogout, onBack, onTabSelect }: Settin
   // Subscribe to locale so labels re-render when the user picks a different language.
   const locale = useLocaleStore((s) => s.locale);
   const t = useLocaleStore((s) => s.t);
+  const hasCalendar = useHasCalendar();
+  const hasContacts = useHasContacts();
+  const hasFiles = useHasFiles();
+  const unavailableTabs = React.useMemo(() => {
+    const set = new Set<Tab>();
+    if (!hasCalendar) set.add('calendar');
+    if (!hasContacts) set.add('contacts');
+    if (!hasFiles) set.add('files');
+    return set;
+  }, [hasCalendar, hasContacts, hasFiles]);
   const groupedTabs = React.useMemo(() => {
     void locale; // dependency: re-translate on locale change
     return groupTabs().map((g) => ({
@@ -178,6 +189,7 @@ export default function SettingsScreen({ onLogout, onBack, onTabSelect }: Settin
 
   const handleTabPress = (tab: TabDef) => {
     if (!tab.implemented) return;
+    if (unavailableTabs.has(tab.id)) return;
     setSelectedTab(tab.id);
     onTabSelect?.(tab.id);
   };
@@ -241,7 +253,13 @@ export default function SettingsScreen({ onLogout, onBack, onTabSelect }: Settin
 
               {group.items.map((tab) => {
                 const Icon = tab.icon;
-                const disabled = !tab.implemented;
+                const unavailable = unavailableTabs.has(tab.id);
+                const disabled = !tab.implemented || unavailable;
+                const badgeLabel = !tab.implemented
+                  ? 'Not implemented'
+                  : unavailable
+                    ? 'Unavailable'
+                    : null;
                 return (
                   <Pressable
                     key={tab.id}
@@ -269,9 +287,9 @@ export default function SettingsScreen({ onLogout, onBack, onTabSelect }: Settin
                         </View>
                       )}
                     </View>
-                    {disabled ? (
+                    {badgeLabel ? (
                       <View style={styles.notWorkingBadge}>
-                        <Text style={styles.notWorkingText}>Not implemented</Text>
+                        <Text style={styles.notWorkingText}>{badgeLabel}</Text>
                       </View>
                     ) : (
                       <ChevronRight size={16} color={c.mutedForeground} />