diff --git a/lib/core/errors/auth_exceptions.dart b/lib/core/errors/auth_exceptions.dart
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+/// Custom authentication exceptions for the Sage application.
+/// 
+/// Provides specific, user-friendly error types that map from Supabase errors
+/// to meaningful exceptions that can be handled consistently throughout the app.
+/// Follows clean architecture principles for domain error handling.
+
+/// Base authentication exception
+/// 
+/// All custom auth exceptions extend this base class to provide
+/// a common interface for error handling throughout the application.
+abstract class AuthException implements Exception {
+  /// User-friendly error message
+  final String message;
+  
+  /// Optional error code for programmatic handling
+  final String? code;
+  
+  /// Optional underlying error for debugging
+  final dynamic originalError;
+  
+  /// Creates a new AuthException
+  const AuthException({
+    required this.message,
+    this.code,
+    this.originalError,
+  });
+  
+  @override
+  String toString() => 'AuthException: $message';
+}
+
+/// Exception thrown when user provides invalid credentials
+class InvalidCredentialsException extends AuthException {
+  const InvalidCredentialsException({
+    String message = 'Invalid email or password',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'INVALID_CREDENTIALS',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when user is not found in the system
+class UserNotFoundException extends AuthException {
+  const UserNotFoundException({
+    String message = 'User not found',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'USER_NOT_FOUND',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when password doesn't meet security requirements
+class WeakPasswordException extends AuthException {
+  const WeakPasswordException({
+    String message = 'Password does not meet security requirements',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'WEAK_PASSWORD',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when trying to register with an already used email
+class EmailAlreadyInUseException extends AuthException {
+  const EmailAlreadyInUseException({
+    String message = 'Email address is already in use',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'EMAIL_ALREADY_IN_USE',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when network operations fail
+class NetworkException extends AuthException {
+  const NetworkException({
+    String message = 'Network connection failed',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'NETWORK_ERROR',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when user session has expired
+class SessionExpiredException extends AuthException {
+  const SessionExpiredException({
+    String message = 'Your session has expired. Please sign in again.',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'SESSION_EXPIRED',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when email verification is required
+class EmailNotVerifiedException extends AuthException {
+  const EmailNotVerifiedException({
+    String message = 'Please verify your email address before continuing',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'EMAIL_NOT_VERIFIED',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when too many login attempts are made
+class TooManyRequestsException extends AuthException {
+  const TooManyRequestsException({
+    String message = 'Too many requests. Please try again later.',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'TOO_MANY_REQUESTS',
+          originalError: originalError,
+        );
+}
+
+/// Exception thrown when authentication is disabled by administrator
+class AuthDisabledException extends AuthException {
+  const AuthDisabledException({
+    String message = 'Authentication is currently disabled',
+    String? code,
+    dynamic originalError,
+  }) : super(
+          message: message,
+          code: code ?? 'AUTH_DISABLED',
+          originalError: originalError,
+        );
+}
+
+/// Utility class for converting Supabase errors to custom exceptions
+/// 
+/// Provides a centralized way to map Supabase error responses
+/// to our custom exception types with appropriate error messages.
+class AuthExceptionFactory {
+  /// Converts a Supabase error to a custom AuthException
+  /// 
+  /// [error] - The error object returned by Supabase
+  /// Returns the appropriate custom AuthException
+  static AuthException fromSupabaseError(dynamic error) {
+    if (error == null) {
+      return const NetworkException(message: 'Unknown error occurred');
+    }
+    
+    // Extract error information from Supabase error
+    String errorMessage = '';
+    String? errorCode;
+    
+    if (error is Map) {
+      errorMessage = error['message']?.toString() ?? error['error']?.toString() ?? '';
+      errorCode = error['code']?.toString();
+    } else {
+      errorMessage = error.toString();
+    }
+    
+    // Normalize error message to lowercase for comparison
+    final lowerMessage = errorMessage.toLowerCase();
+    
+    // Map common Supabase errors to custom exceptions
+    if (lowerMessage.contains('invalid login credentials') ||
+        lowerMessage.contains('wrong password') ||
+        lowerMessage.contains('invalid email')) {
+      return InvalidCredentialsException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Invalid email or password',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('user not found') ||
+        lowerMessage.contains('no user found') ||
+        lowerMessage.contains('user does not exist')) {
+      return UserNotFoundException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'User not found',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('weak password') ||
+        lowerMessage.contains('password too short') ||
+        lowerMessage.contains('password should be')) {
+      return WeakPasswordException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Password does not meet security requirements',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('already registered') ||
+        lowerMessage.contains('email already in use') ||
+        lowerMessage.contains('duplicate')) {
+      return EmailAlreadyInUseException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Email address is already in use',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('email not confirmed') ||
+        lowerMessage.contains('email not verified') ||
+        lowerMessage.contains('please verify your email')) {
+      return EmailNotVerifiedException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Please verify your email address before continuing',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('too many requests') ||
+        lowerMessage.contains('rate limit') ||
+        lowerMessage.contains('try again later')) {
+      return TooManyRequestsException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Too many requests. Please try again later.',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('network') ||
+        lowerMessage.contains('connection') ||
+        lowerMessage.contains('timeout') ||
+        lowerMessage.contains('offline')) {
+      return NetworkException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Network connection failed',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('session') && lowerMessage.contains('expired')) {
+      return SessionExpiredException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Your session has expired. Please sign in again.',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    if (lowerMessage.contains('auth') && lowerMessage.contains('disabled')) {
+      return AuthDisabledException(
+        message: _extractUserFriendlyMessage(errorMessage) ?? 'Authentication is currently disabled',
+        code: errorCode,
+        originalError: error,
+      );
+    }
+    
+    // Fallback for unknown errors
+    return AuthException(
+      message: _extractUserFriendlyMessage(errorMessage) ?? 'Authentication failed',
+      code: errorCode,
+      originalError: error,
+    );
+  }
+  
+  /// Extracts a user-friendly message from Supabase error
+  /// 
+  /// [errorMessage] - The raw error message from Supabase
+  /// Returns a cleaned, user-friendly message or null if not extractable
+  static String? _extractUserFriendlyMessage(String errorMessage) {
+    if (errorMessage.isEmpty) return null;
+    
+    // Remove technical prefixes and clean up the message
+    String cleaned = errorMessage;
+    
+    // Remove common prefixes
+    cleaned = cleaned.replaceFirst(RegExp(r'^Exception: '), '');
+    cleaned = cleaned.replaceFirst(RegExp(r'^Error: '), '');
+    cleaned = cleaned.replaceFirst(RegExp(r'^AuthException: '), '');
+    
+    // Remove double quotes if present
+    cleaned = cleaned.replaceAll('"', '');
+    
+    // Trim whitespace
+    cleaned = cleaned.trim();
+    
+    // Capitalize first letter
+    if (cleaned.isNotEmpty) {
+      cleaned = cleaned[0].toUpperCase() + cleaned.substring(1);
+    }
+    
+    return cleaned.isNotEmpty ? cleaned : null;
+  }
+}
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