diff --git a/app/controllers/api/base_controller.rb b/app/controllers/api/base_controller.rb
index 94950b0..172ddf6 100644
--- a/app/controllers/api/base_controller.rb
+++ b/app/controllers/api/base_controller.rb
@@ -167,10 +167,12 @@ def handle_internal_error(exception)
 
   # Format validation errors into structured array
   def format_validation_errors(errors)
-    errors.messages.map do |field, messages|
+    errors.attribute_names.map do |field|
+      field_errors = errors.where(field)
       {
         field: field,
-        messages: messages,
+        codes: field_errors.filter_map { |e| "#{field}.#{e.type}" if e.type.is_a?(Symbol) },
+        messages: field_errors.map(&:message),
         full_messages: errors.full_messages_for(field)
       }
     end
diff --git a/app/models/user.rb b/app/models/user.rb
index 7e07b1d..e3e95d8 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -258,20 +258,9 @@ def generate_sso_link
   def password_complexity
     return if password.blank?
 
-    unless password.match?(/[a-z]/)
-      errors.add(:password, 'must include at least one lowercase letter')
-    end
-
-    unless password.match?(/[A-Z]/)
-      errors.add(:password, 'must include at least one uppercase letter')
-    end
-
-    unless password.match?(/\d/)
-      errors.add(:password, 'must include at least one number')
-    end
-
-    unless password.match?(PASSWORD_SPECIAL_CHAR_REGEX)
-      errors.add(:password, 'must include at least one special character')
-    end
+    errors.add(:password, :missing_lowercase, message: 'must include at least one lowercase letter') unless password.match?(/[a-z]/)
+    errors.add(:password, :missing_uppercase, message: 'must include at least one uppercase letter') unless password.match?(/[A-Z]/)
+    errors.add(:password, :missing_number, message: 'must include at least one number') unless password.match?(/\d/)
+    errors.add(:password, :missing_special_char, message: 'must include at least one special character') unless password.match?(PASSWORD_SPECIAL_CHAR_REGEX)
   end
 end
diff --git a/spec/models/user_password_spec.rb b/spec/models/user_password_spec.rb
new file mode 100644
index 0000000..af0bef1
--- /dev/null
+++ b/spec/models/user_password_spec.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe User, type: :model do
+  describe '#password_complexity' do
+    let(:base_attrs) { { email: 'test@example.com', name: 'Test User' } }
+
+    subject(:user) { User.new(base_attrs.merge(password: password)) }
+
+    context 'when password is missing a special character' do
+      let(:password) { 'NoSpecial1Abc' }
+
+      it 'adds :missing_special_char error code' do
+        user.valid?
+        error = user.errors.where(:password).find { |e| e.type == :missing_special_char }
+        expect(error).to be_present
+      end
+    end
+
+    context 'when password is missing an uppercase letter' do
+      let(:password) { 'nouppercase1!' }
+
+      it 'adds :missing_uppercase error code' do
+        user.valid?
+        error = user.errors.where(:password).find { |e| e.type == :missing_uppercase }
+        expect(error).to be_present
+      end
+    end
+
+    context 'when password is missing a lowercase letter' do
+      let(:password) { 'NOLOWER1!' }
+
+      it 'adds :missing_lowercase error code' do
+        user.valid?
+        error = user.errors.where(:password).find { |e| e.type == :missing_lowercase }
+        expect(error).to be_present
+      end
+    end
+
+    context 'when password is missing a number' do
+      let(:password) { 'NoNumbers!Ab' }
+
+      it 'adds :missing_number error code' do
+        user.valid?
+        error = user.errors.where(:password).find { |e| e.type == :missing_number }
+        expect(error).to be_present
+      end
+    end
+
+    context 'when password meets all complexity requirements' do
+      let(:password) { 'Valid1!Pass' }
+
+      it 'has no complexity error codes' do
+        user.valid?
+        complexity_types = %i[missing_lowercase missing_uppercase missing_number missing_special_char]
+        complexity_errors = user.errors.where(:password).select { |e| complexity_types.include?(e.type) }
+        expect(complexity_errors).to be_empty
+      end
+    end
+  end
+end