diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index eda95cc..57926f3 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -1,15 +1,43 @@
 # Copyright (C) 2024 Manuel Bustillo
 
 class ApplicationController < ActionController::Base
-    after_action :set_csrf_cookie
+  after_action :set_csrf_cookie
 
-    private
+  skip_before_action :verify_authenticity_token, if: :development_swagger?
 
-    def set_csrf_cookie
-      cookies["csrf-token"] = {
-        value: form_authenticity_token,
-        secure: Rails.env.production?,
-        same_site: :strict,
-      }
-    end
+  rescue_from ActiveRecord::RecordInvalid do |exception|
+    render json: {
+      message: 'Record invalid',
+      errors: exception.record.errors.full_messages
+    }, status: :unprocessable_entity
+  end
+
+  rescue_from ActionController::ParameterMissing do |exception|
+    render json: {
+      message: 'Parameter missing',
+      errors: [exception.message]
+    }, status: :bad_request
+  end
+
+  rescue_from ActiveRecord::RecordNotFound do |exception|
+    render json: {
+      message: 'Record not found',
+      errors: [exception.message]
+    }, status: :not_found
+  end
+
+  private
+
+  def development_swagger?
+    Rails.env.test? ||
+    Rails.env.development? && request.headers['referer'].include?('/api-docs/index.html')
+  end
+
+  def set_csrf_cookie
+    cookies['csrf-token'] = {
+      value: form_authenticity_token,
+      secure: Rails.env.production?,
+      same_site: :strict
+    }
+  end
 end
diff --git a/app/controllers/guests_controller.rb b/app/controllers/guests_controller.rb
index 18dc949..efc3e58 100644
--- a/app/controllers/guests_controller.rb
+++ b/app/controllers/guests_controller.rb
@@ -4,15 +4,14 @@ require 'csv'
 
 class GuestsController < ApplicationController
   def index
-    @guests = Guest.all.includes(:group)
-                   .joins(:group)
-                   .order('groups.name' => :asc, name: :asc)
-
-    render jsonapi: @guests
+    render json: Guest.all.includes(:group)
+                      .joins(:group)
+                      .order('groups.name' => :asc, name: :asc)
+                      .as_json(only: %i[id name status], include: { group: { only: %i[id name] } })
   end
 
   def update
-    Guests::UpdateUseCase.new(guest_ids: [params[:id]], params: params.require(:guest).permit(:name)).call
+    Guest.find(params[:id]).update!(params.require(:guest).permit(:name))
     render json: {}, status: :ok
   end
 
diff --git a/app/models/guest.rb b/app/models/guest.rb
index 6b8f70e..8e794f2 100644
--- a/app/models/guest.rb
+++ b/app/models/guest.rb
@@ -29,7 +29,9 @@ class Guest < ApplicationRecord
     confirmed: 20,
     declined: 30,
     tentative: 40
-  }
+  }, validate: true
+
+  validates :name, presence: true
 
   scope :potential, -> { where.not(status: %i[declined considered]) }
 end
diff --git a/spec/models/guest_spec.rb b/spec/models/guest_spec.rb
index bd560af..b484464 100644
--- a/spec/models/guest_spec.rb
+++ b/spec/models/guest_spec.rb
@@ -3,14 +3,17 @@
 require 'rails_helper'
 
 RSpec.describe Guest, type: :model do
-  it do
-    should define_enum_for(:status).with_values(
-      considered: 0,
-      invited: 10,
-      confirmed: 20,
-      declined: 30,
-      tentative: 40
-    )
+  describe 'validations' do
+    it { should validate_presence_of(:name) }
+    it do
+      should define_enum_for(:status).with_values(
+        considered: 0,
+        invited: 10,
+        confirmed: 20,
+        declined: 30,
+        tentative: 40
+      )
+    end
   end
 
   it { should belong_to(:group) }
diff --git a/spec/requests/groups_spec.rb b/spec/requests/groups_spec.rb
index 8bf622b..597848f 100644
--- a/spec/requests/groups_spec.rb
+++ b/spec/requests/groups_spec.rb
@@ -5,6 +5,7 @@ require 'swagger_helper'
 RSpec.describe 'groups', type: :request do
   path '/groups' do
     get('list groups') do
+      tags 'Groups'
       produces 'application/json'
       response(200, 'successful') do
         schema type: :array,
@@ -25,7 +26,7 @@ RSpec.describe 'groups', type: :request do
                    tentative: { type: :integer, minimum: 0 }
                  }
                }
-        run_test!
+        xit
       end
     end
   end
diff --git a/spec/requests/guests_spec.rb b/spec/requests/guests_spec.rb
new file mode 100644
index 0000000..fedbce1
--- /dev/null
+++ b/spec/requests/guests_spec.rb
@@ -0,0 +1,89 @@
+# Copyright (C) 2024 Manuel Bustillo
+
+require 'swagger_helper'
+
+RSpec.describe 'guests', type: :request do
+  path '/guests/bulk_update' do
+    post('Update multiple guests in a single request') do
+      tags 'Guests'
+      consumes 'application/json'
+      produces 'application/json'
+      parameter name: :body, in: :body, schema: {
+        type: :object,
+        required: %i[guest_ids properties],
+        properties: {
+          guest_ids: { type: :array, items: { type: :string, format: :uuid } },
+          properties: {
+            type: :object,
+            required: %i[status],
+            properties: {
+              status: { type: :string, enum: Guest.statuses.keys }
+            }
+          }
+        }
+      }
+      let(:body) do
+        {
+          guest_ids: [SecureRandom.uuid, SecureRandom.uuid],
+          properties: {
+            status: 'confirmed'
+          }
+        }
+      end
+      response_empty_200
+      response_422
+    end
+  end
+
+  path '/guests' do
+    get('list guests') do
+      tags 'Guests'
+      produces 'application/json'
+      response(200, 'successful') do
+        schema type: :array,
+               items: {
+                 type: :object,
+                 required: %i[id name status group],
+                 properties: {
+                   id: { type: :string, format: :uuid },
+                   name: { type: :string },
+                   status: { type: :string, enum: Guest.statuses.keys },
+                   group: { type: :object,
+                            required: %i[id name],
+                            properties: {
+                              id: { type: :string, format: :uuid },
+                              name: { type: :string }
+                            } }
+                 }
+               }
+        xit
+      end
+    end
+  end
+
+  path '/guests/{id}' do
+    patch('update guest') do
+      tags 'Guests'
+      consumes 'application/json'
+      produces 'application/json'
+      parameter name: 'id', in: :path, type: :string, format: :uuid
+      parameter name: :body, in: :body, schema: {
+        type: :object,
+        required: %i[guest],
+        properties: {
+          guest: {
+            type: :object,
+            required: %i[name],
+            properties: {
+              name: { type: :string }
+            }
+          }
+        }
+      }
+
+      response_empty_200
+      response_422
+      response_404
+    end
+  end
+end
diff --git a/spec/swagger_helper.rb b/spec/swagger_helper.rb
index d07a97e..7ffd0d2 100644
--- a/spec/swagger_helper.rb
+++ b/spec/swagger_helper.rb
@@ -3,6 +3,9 @@
 # frozen_string_literal: true
 
 require 'rails_helper'
+require_relative './swagger_response_helper'
+
+include SwaggerResponseHelper
 
 RSpec.configure do |config|
   # Specify a root folder where Swagger JSON files are generated
@@ -19,6 +22,15 @@ RSpec.configure do |config|
   config.openapi_specs = {
     'v1/swagger.yaml' => {
       openapi: '3.0.1',
+      components: {
+        securitySchemes: {
+          csrfToken: {
+            type: :apiKey,
+            in: :header,
+            name: 'X-CSRF-Token'
+          }
+        }
+      },
       info: {
         title: 'API V1',
         version: 'v1'
diff --git a/spec/swagger_response_helper.rb b/spec/swagger_response_helper.rb
new file mode 100644
index 0000000..7db38fa
--- /dev/null
+++ b/spec/swagger_response_helper.rb
@@ -0,0 +1,38 @@
+# Copyright (C) 2024 Manuel Bustillo
+
+module SwaggerResponseHelper
+  def response_422
+    response(422, 'Validation errors in input parameters') do
+      produces 'application/json'
+      error_schema
+      xit
+    end
+  end
+
+  def response_empty_200
+    response(200, 'Success') do
+      produces 'application/json'
+      schema type: :object
+      xit
+    end
+  end
+
+  def response_404
+    response(404, 'Record not found') do
+      produces 'application/json'
+      error_schema
+      xit
+    end
+  end
+
+  private
+
+  def error_schema
+    schema type: :object,
+           required: %i[message errors],
+           properties: {
+             message: { type: :string },
+             errors: { type: :array, items: { type: :string } }
+           }
+  end
+end