diff --git a/static/js/index.js b/static/js/index.js
index 3ecdabe..407907a 100644
--- a/static/js/index.js
+++ b/static/js/index.js
@@ -13,6 +13,8 @@ window.app = Vue.createApp({
       currencies: [],
       settings: null,
       isAdmin: false,
+      isSuperUser: false,
+      castleWalletConfigured: false,
       expenseDialog: {
         show: false,
         description: '',
@@ -104,16 +106,21 @@ window.app = Vue.createApp({
     },
     async loadSettings() {
       try {
+        // Try with admin key first to check settings
         const response = await LNbits.api.request(
           'GET',
           '/castle/api/v1/settings',
-          this.g.user.wallets[0].adminkey
+          this.g.user.wallets[0].inkey
         )
         this.settings = response.data
-        this.isAdmin = true
+        this.castleWalletConfigured = !!(this.settings && this.settings.castle_wallet_id)
+
+        // Check if user is super user by seeing if they can access admin features
+        this.isSuperUser = this.g.user.super_user || false
+        this.isAdmin = this.g.user.admin || this.isSuperUser
       } catch (error) {
-        // Not admin or settings not available
-        this.isAdmin = false
+        // Settings not available
+        this.castleWalletConfigured = false
       }
     },
     showSettingsDialog() {
@@ -121,6 +128,14 @@ window.app = Vue.createApp({
       this.settingsDialog.show = true
     },
     async submitSettings() {
+      if (!this.settingsDialog.castleWalletId) {
+        this.$q.notify({
+          type: 'warning',
+          message: 'Castle Wallet ID is required'
+        })
+        return
+      }
+
       this.settingsDialog.loading = true
       try {
         await LNbits.api.request(
diff --git a/templates/castle/index.html b/templates/castle/index.html
index 4878b80..07c0340 100644
--- a/templates/castle/index.html
+++ b/templates/castle/index.html
@@ -16,15 +16,37 @@
             <h5 class="q-my-none">🏰 Castle Accounting</h5>
             <p class="q-mb-none">Track expenses, receivables, and balances for the collective</p>
           </div>
-          <div class="col-auto" v-if="isAdmin">
+          <div class="col-auto" v-if="isSuperUser">
             <q-btn flat round icon="settings" @click="showSettingsDialog">
-              <q-tooltip>Settings</q-tooltip>
+              <q-tooltip>Settings (Super User Only)</q-tooltip>
             </q-btn>
           </div>
         </div>
       </q-card-section>
     </q-card>
 
+    <!-- Setup Warning -->
+    <q-banner v-if="!castleWalletConfigured && isSuperUser" class="bg-warning text-white" rounded>
+      <template v-slot:avatar>
+        <q-icon name="warning" color="white"></q-icon>
+      </template>
+      <div>
+        <strong>Setup Required:</strong> Castle Wallet ID must be configured before the extension can function.
+      </div>
+      <template v-slot:action>
+        <q-btn flat color="white" label="Configure Now" @click="showSettingsDialog"></q-btn>
+      </template>
+    </q-banner>
+
+    <q-banner v-if="!castleWalletConfigured && !isSuperUser" class="bg-info text-white" rounded>
+      <template v-slot:avatar>
+        <q-icon name="info" color="white"></q-icon>
+      </template>
+      <div>
+        <strong>Setup Required:</strong> This extension requires configuration by the super user before it can be used.
+      </div>
+    </q-banner>
+
     <!-- User Balance Card -->
     <q-card>
       <q-card-section>
@@ -66,8 +88,15 @@
       <q-card-section>
         <h6 class="q-my-none q-mb-md">Quick Actions</h6>
         <div class="row q-gutter-sm">
-          <q-btn color="primary" @click="expenseDialog.show = true">
+          <q-btn
+            color="primary"
+            @click="expenseDialog.show = true"
+            :disable="!castleWalletConfigured"
+          >
             Add Expense
+            <q-tooltip v-if="!castleWalletConfigured">
+              Castle wallet must be configured first
+            </q-tooltip>
           </q-btn>
           <q-btn color="secondary" @click="loadTransactions">
             View Transactions
@@ -248,12 +277,22 @@
     <q-form @submit="submitSettings" class="q-gutter-md">
       <div class="text-h6 q-mb-md">Castle Settings</div>
 
+      <q-banner v-if="!isSuperUser" class="bg-warning text-dark q-mb-md" dense rounded>
+        <template v-slot:avatar>
+          <q-icon name="lock" color="orange"></q-icon>
+        </template>
+        <div class="text-caption">
+          <strong>Super User Only:</strong> Only the super user can modify these settings.
+        </div>
+      </q-banner>
+
       <q-input
         filled
         dense
         v-model.trim="settingsDialog.castleWalletId"
         label="Castle Wallet ID *"
         placeholder="The wallet ID that represents the Castle"
+        :readonly="!isSuperUser"
       ></q-input>
 
       <div class="text-caption text-grey">
@@ -261,10 +300,18 @@
       </div>
 
       <div class="row q-mt-lg">
-        <q-btn unelevated color="primary" type="submit" :loading="settingsDialog.loading">
+        <q-btn
+          v-if="isSuperUser"
+          unelevated
+          color="primary"
+          type="submit"
+          :loading="settingsDialog.loading"
+        >
           Save Settings
         </q-btn>
-        <q-btn v-close-popup flat color="grey" class="q-ml-auto">Cancel</q-btn>
+        <q-btn v-close-popup flat color="grey" :class="isSuperUser ? 'q-ml-auto' : ''">
+          {% raw %}{{ isSuperUser ? 'Cancel' : 'Close' }}{% endraw %}
+        </q-btn>
       </div>
     </q-form>
   </q-card>
diff --git a/views_api.py b/views_api.py
index 7db76d9..d2bc6f4 100644
--- a/views_api.py
+++ b/views_api.py
@@ -1,8 +1,13 @@
 from http import HTTPStatus
 
 from fastapi import APIRouter, Depends, HTTPException
-from lnbits.core.models import WalletTypeInfo
-from lnbits.decorators import require_admin_key, require_invoice_key
+from lnbits.core.models import User, WalletTypeInfo
+from lnbits.decorators import (
+    check_super_user,
+    check_user_exists,
+    require_admin_key,
+    require_invoice_key,
+)
 from lnbits.utils.exchange_rates import allowed_currencies, fiat_amount_as_satoshis
 
 from .crud import (
@@ -37,6 +42,20 @@ from .services import get_settings, update_settings
 castle_api_router = APIRouter()
 
 
+# ===== HELPER FUNCTIONS =====
+
+
+async def check_castle_wallet_configured() -> str:
+    """Ensure castle wallet is configured, return wallet_id"""
+    settings = await get_settings("admin")
+    if not settings or not settings.castle_wallet_id:
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST,
+            detail="Castle wallet not configured. Please contact the super user to configure the Castle wallet in settings.",
+        )
+    return settings.castle_wallet_id
+
+
 # ===== UTILITY ENDPOINTS =====
 
 
@@ -459,18 +478,27 @@ async def api_pay_user(
 
 @castle_api_router.get("/api/v1/settings")
 async def api_get_settings(
-    wallet: WalletTypeInfo = Depends(require_admin_key),
+    user: User = Depends(check_user_exists),
 ) -> CastleSettings:
-    """Get Castle settings (admin only)"""
+    """Get Castle settings"""
     user_id = "admin"
-    return await get_settings(user_id)
+    settings = await get_settings(user_id)
+    # Return empty settings if not configured (so UI can show setup screen)
+    if not settings:
+        return CastleSettings()
+    return settings
 
 
 @castle_api_router.put("/api/v1/settings")
 async def api_update_settings(
     data: CastleSettings,
-    wallet: WalletTypeInfo = Depends(require_admin_key),
+    user: User = Depends(check_super_user),
 ) -> CastleSettings:
-    """Update Castle settings (admin only)"""
+    """Update Castle settings (super user only)"""
+    if not data.castle_wallet_id:
+        raise HTTPException(
+            status_code=HTTPStatus.BAD_REQUEST,
+            detail="Castle wallet ID is required",
+        )
     user_id = "admin"
     return await update_settings(user_id, data)