diff --git a/create_messages_table.sql b/create_messages_table.sql
new file mode 100644
index 0000000..65b2697
--- /dev/null
+++ b/create_messages_table.sql
@@ -0,0 +1,17 @@
+-- Criar tabela de mensagens no schema gpi
+CREATE TABLE IF NOT EXISTS gpi.messages (
+    id uuid DEFAULT uuid_generate_v4() PRIMARY KEY,
+    organization_id uuid REFERENCES gpi.organizations(id) ON DELETE CASCADE,
+    from_user_id uuid REFERENCES gpi.users(id) ON DELETE SET NULL,
+    to_user_id uuid REFERENCES gpi.users(id) ON DELETE SET NULL,
+    message text NOT NULL,
+    is_read boolean DEFAULT false,
+    read_at timestamp with time zone,
+    is_archived boolean DEFAULT false,
+    is_deleted_by_recipient boolean DEFAULT false,
+    created_at timestamp with time zone DEFAULT now(),
+    updated_at timestamp with time zone DEFAULT now()
+);
+
+-- Permissões para as roles do Supabase
+GRANT ALL ON gpi.messages TO postgres, anon, authenticated, service_role;
diff --git a/src/client/components/TeamPresence.tsx b/src/client/components/TeamPresence.tsx
index 0044a5c..69d9d6a 100644
--- a/src/client/components/TeamPresence.tsx
+++ b/src/client/components/TeamPresence.tsx
@@ -72,7 +72,7 @@ export const TeamPresence: React.FC = () => {
 
     // Create a map of pending messages by recipient ID
     const pendingMessagesByRecipient = new Map(
-        pendingMessages.map(msg => [msg.toUser?.email, msg])
+        (pendingMessages || []).map(msg => [msg.toUser?.email, msg])
     );
 
     const handleMemberClick = (member: OrganizationMember) => {
@@ -102,11 +102,11 @@ export const TeamPresence: React.FC = () => {
             <div className="px-6 py-3">
                 <div className="mb-2">
                     <span className="text-[10px] font-bold text-text-muted uppercase tracking-[0.2em]">
-                        Equipe ({activeUsers.length}/{allMembers.length} online)
+                        Equipe ({(activeUsers || []).length}/{(allMembers || []).length} online)
                     </span>
                 </div>
                 <div className="flex flex-wrap gap-2">
-                    {allMembers.map((member) => {
+                    {(allMembers || []).map((member) => {
                         const isOnline = activeUserLogtoIds.has(member.logto_id);
                         const isCurrentUser = member.logto_id === appUser?.logtoId;
                         const hasPendingMessage = pendingMessagesByRecipient.has(member.email);
diff --git a/src/client/context/AuthContext.tsx b/src/client/context/AuthContext.tsx
index 8dca2d0..f409f00 100644
--- a/src/client/context/AuthContext.tsx
+++ b/src/client/context/AuthContext.tsx
@@ -9,7 +9,7 @@ interface AuthProviderProps {
 }
 
 const defaultUser: AppUser = {
-    id: 'guest-user',
+    id: '00000000-0000-0000-0000-000000000000',
     email: 'guest@gpi.app',
     name: 'Guest User',
     role: 'user',
@@ -18,7 +18,7 @@ const defaultUser: AppUser = {
     updatedAt: new Date().toISOString()
 };
 
-const DEFAULT_ORGANIZATION_ID = 'default-org';
+const DEFAULT_ORGANIZATION_ID = '00000000-0000-0000-0000-000000000001';
 const DEFAULT_ORGANIZATION_NAME = 'Organização Padrão';
 
 export const AuthProvider: React.FC<AuthProviderProps> = ({ children }) => {
diff --git a/src/client/contexts/NotificationContext.tsx b/src/client/contexts/NotificationContext.tsx
index b2fcd1a..51fcc23 100644
--- a/src/client/contexts/NotificationContext.tsx
+++ b/src/client/contexts/NotificationContext.tsx
@@ -83,7 +83,7 @@ export const NotificationProvider: React.FC<{ children: React.ReactNode }> = ({
         }
     }, [isSignedIn, fetchNotifications]);
 
-    const unreadCount = notifications.filter(n => !n.isRead).length;
+    const unreadCount = (notifications || []).filter(n => !n.isRead).length;
 
     return (
         <NotificationContext.Provider value={{
diff --git a/src/server/controllers/userController.ts b/src/server/controllers/userController.ts
index c6ad2ee..2080ef5 100644
--- a/src/server/controllers/userController.ts
+++ b/src/server/controllers/userController.ts
@@ -63,7 +63,7 @@ export const getCurrentUser = async (req: AuthRequest, res: Response) => {
     try {
         if (!req.appUser) {
             return res.json({
-                id: 'guest-user',
+                id: '00000000-0000-0000-0000-000000000000',
                 email: 'guest@gpi.app',
                 name: 'Guest User',
                 role: 'user'
diff --git a/src/server/middleware/authMiddleware.ts b/src/server/middleware/authMiddleware.ts
index fec4164..75600b0 100644
--- a/src/server/middleware/authMiddleware.ts
+++ b/src/server/middleware/authMiddleware.ts
@@ -18,12 +18,12 @@ declare module 'express-serve-static-core' {
 
 export const extractUser = async (req: Request, res: Response, next: NextFunction) => {
     req.appUser = {
-        id: 'guest-user',
+        id: '00000000-0000-0000-0000-000000000000',
         logtoId: 'guest',
         email: 'guest@gpi.app',
         name: 'Guest User',
         role: 'user',
-        organizationId: req.headers['x-organization-id'] as string || 'default-org',
+        organizationId: req.headers['x-organization-id'] as string || '00000000-0000-0000-0000-000000000001',
         organizationRole: 'user'
     };
     next();