diff --git a/Gemfile.lock b/Gemfile.lock
index 698d330ea..3a53c8c27 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -253,7 +253,10 @@ GEM
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    json (2.18.1)
+    json (2.19.2)
+    json-schema (6.2.0)
+      addressable (~> 2.8)
+      bigdecimal (>= 3.1, < 5)
     jwt (2.2.3)
     kaminari (1.2.2)
       activesupport (>= 4.1.0)
@@ -280,6 +283,8 @@ GEM
       net-smtp
     marcel (1.0.4)
     matrix (0.4.3)
+    mcp (0.8.0)
+      json-schema (>= 4.1)
     method_source (1.1.0)
     mini_magick (5.3.1)
       logger
@@ -455,18 +460,19 @@ GEM
     rspec-support (3.13.7)
     rspec_junit_formatter (0.6.0)
       rspec-core (>= 2, < 4, != 2.12.0)
-    rubocop (1.80.1)
+    rubocop (1.85.1)
       json (~> 2.3)
       language_server-protocol (~> 3.17.0.2)
       lint_roller (~> 1.1.0)
+      mcp (~> 0.6)
       parallel (~> 1.10)
       parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 2.9.3, < 3.0)
-      rubocop-ast (>= 1.46.0, < 2.0)
+      rubocop-ast (>= 1.49.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 4.0)
-    rubocop-ast (1.49.0)
+    rubocop-ast (1.49.1)
       parser (>= 3.3.7.2)
       prism (~> 1.7)
     rubocop-capybara (2.22.1)
@@ -488,9 +494,9 @@ GEM
       rack (>= 1.1)
       rubocop (>= 1.75.0, < 2.0)
       rubocop-ast (>= 1.44.0, < 2.0)
-    rubocop-rspec (3.6.0)
+    rubocop-rspec (3.9.0)
       lint_roller (~> 1.1)
-      rubocop (~> 1.72, >= 1.72.1)
+      rubocop (~> 1.81)
     rubocop-rspec_rails (2.32.0)
       lint_roller (~> 1.1)
       rubocop (~> 1.72, >= 1.72.1)
diff --git a/app/controllers/api/school_students_controller.rb b/app/controllers/api/school_students_controller.rb
index 430981940..c403fc031 100644
--- a/app/controllers/api/school_students_controller.rb
+++ b/app/controllers/api/school_students_controller.rb
@@ -82,7 +82,7 @@ def create_batch
     # should assume the entire student import has failed.
     def enqueue_batches(students)
       # Raise if a batch is already in progress for this school.
-      raise ConcurrencyExceededForSchool if @school.import_in_progress?
+      raise CreateStudentsJob::ConcurrencyExceededForSchool if @school.import_in_progress?
 
       @batch = GoodJob::Batch.new(description: @school.id)
       @batch.enqueue do
diff --git a/app/dashboards/project_dashboard.rb b/app/dashboards/project_dashboard.rb
index d9e43c22f..b13e80363 100644
--- a/app/dashboards/project_dashboard.rb
+++ b/app/dashboards/project_dashboard.rb
@@ -83,6 +83,6 @@ def display_resource(project)
   end
 
   def permitted_attributes
-    super + [images: []]
+    super + [{ images: [] }]
   end
 end
diff --git a/app/jobs/create_students_job.rb b/app/jobs/create_students_job.rb
index 18f14c386..7dc5688ca 100644
--- a/app/jobs/create_students_job.rb
+++ b/app/jobs/create_students_job.rb
@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
-class ConcurrencyExceededForSchool < StandardError; end
-
 class CreateStudentsJob < ApplicationJob
+  class ConcurrencyExceededForSchool < StandardError; end
+
   retry_on StandardError, wait: :polynomially_longer, attempts: 3 do |_job, e|
     Sentry.capture_exception(e)
     raise e
diff --git a/app/jobs/upload_job.rb b/app/jobs/upload_job.rb
index 0f4021cd6..a72de493f 100644
--- a/app/jobs/upload_job.rb
+++ b/app/jobs/upload_job.rb
@@ -4,10 +4,10 @@
 require 'github_api'
 require 'locales'
 
-class InvalidDirectoryStructureError < StandardError; end
-class DataNotFoundError < StandardError; end
-
 class UploadJob < ApplicationJob
+  class InvalidDirectoryStructureError < StandardError; end
+  class DataNotFoundError < StandardError; end
+
   retry_on StandardError, wait: :polynomially_longer, attempts: 3 do |_job, e|
     Sentry.capture_exception(e)
     raise e
diff --git a/app/models/filesystem_project.rb b/app/models/filesystem_project.rb
index df0891324..3632ba3e2 100644
--- a/app/models/filesystem_project.rb
+++ b/app/models/filesystem_project.rb
@@ -61,13 +61,18 @@ def self.component(file, dir)
     { name:, extension:, content: code, default: }
   end
 
-  def self.file_mime_type(file)
-    Marcel::MimeType.for(File.open(file), name: File.basename(file))
+  def self.file_mime_type(path)
+    File.open(path) do |file|
+      Marcel::MimeType.for(file, name: File.basename(path))
+    end
   end
 
   def self.media(file, dir)
     filename = File.basename(file)
+    # rubocop:disable Style/FileOpen
+    # This is an issue but we can't easily fix it as the returned IO object is used elsewhere.
     io = File.open(dir.join(filename).to_s)
+    # rubocop:enable Style/FileOpen
     { filename:, io: }
   end
 end
diff --git a/lib/concepts/school_student/create_batch.rb b/lib/concepts/school_student/create_batch.rb
index a7c0d6ef3..ad76b3c28 100644
--- a/lib/concepts/school_student/create_batch.rb
+++ b/lib/concepts/school_student/create_batch.rb
@@ -3,15 +3,13 @@
 module SchoolStudent
   class Error < StandardError; end
 
-  class ConcurrencyExceededForSchool < StandardError; end
-
   class CreateBatch
     class << self
       def call(school:, school_students_params:, token:)
         response = OperationResponse.new
         response[:job_id] = create_batch(school, school_students_params, token)
         response
-      rescue ConcurrencyExceededForSchool => e
+      rescue CreateStudentsJob::ConcurrencyExceededForSchool => e
         response[:error] = e
         response[:error_type] = :job_concurrency_error
         response
diff --git a/lib/tasks/test_seeds.rake b/lib/tasks/test_seeds.rake
index 104b598cb..9e03704bd 100644
--- a/lib/tasks/test_seeds.rake
+++ b/lib/tasks/test_seeds.rake
@@ -2,7 +2,6 @@
 
 require_relative 'seeds_helper'
 
-# rubocop:disable Rails/Output
 namespace :test_seeds do
   include SeedsHelper
 
@@ -72,4 +71,3 @@ namespace :test_seeds do
     end
   end
 end
-# rubocop:enable Rails/Output
diff --git a/spec/concepts/class_member/create_spec.rb b/spec/concepts/class_member/create_spec.rb
index e6b67b185..a4744dd98 100644
--- a/spec/concepts/class_member/create_spec.rb
+++ b/spec/concepts/class_member/create_spec.rb
@@ -48,14 +48,14 @@
 
   it 'assigns the student_id' do
     response = described_class.call(school_class:, students:, teachers:)
-    response_students = response[:class_members].select { |member| member.is_a?(ClassStudent) }
+    response_students = response[:class_members].grep(ClassStudent)
     expect(response_students.map(&:student_id)).to match_array(student_ids)
   end
 
   it 'assigns the teacher_id' do
     teacher_ids = teachers.map(&:id)
     response = described_class.call(school_class:, students:, teachers:)
-    response_teachers = response[:class_members].select { |member| member.is_a?(ClassTeacher) }
+    response_teachers = response[:class_members].grep(ClassTeacher)
     expect(response_teachers.map(&:teacher_id)).to match_array(teacher_ids)
   end
 
@@ -160,14 +160,14 @@
 
         it 'assigns the successful students' do
           response = described_class.call(school_class:, students: new_students, teachers:)
-          response_students = response[:class_members].select { |member| member.is_a?(ClassStudent) }
+          response_students = response[:class_members].grep(ClassStudent)
           expect(response_students.map(&:student_id)).to match_array(student_ids)
         end
 
         it 'assigns the successful teachers' do
           teacher_ids = teachers.map(&:id)
           response = described_class.call(school_class:, students: new_students, teachers:)
-          response_teachers = response[:class_members].select { |member| member.is_a?(ClassTeacher) }
+          response_teachers = response[:class_members].grep(ClassTeacher)
           expect(response_teachers.map(&:teacher_id)).to match_array(teacher_ids)
         end
 
diff --git a/spec/features/class_member/creating_a_batch_of_class_members_spec.rb b/spec/features/class_member/creating_a_batch_of_class_members_spec.rb
index 95cbabff5..f5ad035ba 100644
--- a/spec/features/class_member/creating_a_batch_of_class_members_spec.rb
+++ b/spec/features/class_member/creating_a_batch_of_class_members_spec.rb
@@ -166,7 +166,7 @@
   end
 
   context "with users that don't exist in Profile" do
-    unknown_user_id = SecureRandom.uuid
+    let(:unknown_user_id) { SecureRandom.uuid }
 
     let(:invalid_params) do
       {
diff --git a/spec/jobs/upload_job_spec.rb b/spec/jobs/upload_job_spec.rb
index 2537c188e..61d5bb86a 100644
--- a/spec/jobs/upload_job_spec.rb
+++ b/spec/jobs/upload_job_spec.rb
@@ -265,7 +265,7 @@
     it 'raises DataNotFoundError' do
       expect do
         described_class.perform_now(payload)
-      end.to raise_error(DataNotFoundError)
+      end.to raise_error(UploadJob::DataNotFoundError)
     end
   end
 
diff --git a/spec/lib/profile_api_client_spec.rb b/spec/lib/profile_api_client_spec.rb
index 37340a8c4..3a2c40def 100644
--- a/spec/lib/profile_api_client_spec.rb
+++ b/spec/lib/profile_api_client_spec.rb
@@ -239,7 +239,7 @@ def delete_safeguarding_flag
     end
 
     it 'raises 422 exception with the relevant message if 400 status code is returned' do
-      response = { errors: [message: 'The password is well dodgy'] }
+      response = { errors: [{ message: 'The password is well dodgy' }] }
       stub_request(:post, create_students_url)
         .to_return(status: 400, body: response.to_json, headers: { 'content-type' => 'application/json' })
 
@@ -284,7 +284,7 @@ def create_school_student
     it_behaves_like 'a request that handles an unexpected response status', :post, url: -> { create_students_url }, status: 202
 
     it 'raises 422 exception with the relevant message if 400 status code is returned' do
-      response = { errors: [message: 'The password is well dodgy'] }
+      response = { errors: [{ message: 'The password is well dodgy' }] }
       stub_request(:post, create_students_url)
         .to_return(status: 400, body: response.to_json, headers: { 'content-type' => 'application/json' })
 
@@ -356,7 +356,7 @@ def create_school_students
     it_behaves_like 'a request that handles an unexpected response status', :post, url: -> { create_students_sso_url }, status: 202
 
     it 'raises 422 exception with the relevant message if 400 status code is returned' do
-      response = { errors: [message: 'The password is well dodgy'] }
+      response = { errors: [{ message: 'The password is well dodgy' }] }
       stub_request(:post, create_students_sso_url)
         .to_return(status: 400, body: response.to_json, headers: { 'content-type' => 'application/json' })
 
@@ -478,7 +478,7 @@ def list_school_students
     end
 
     it 'raises 422 exception with the relevant message if 400 status code is returned' do
-      response = { errors: [message: 'The username is well dodgy'] }
+      response = { errors: [{ message: 'The username is well dodgy' }] }
       stub_request(:patch, update_student_url)
         .to_return(status: 400, body: response.to_json, headers: { 'content-type' => 'application/json' })