Add cop to check GraphQL field/argument description

- Fix typo
- Remove reference to outdated files
- Restrict directories to `app/graphql` and `ee/app/graphql` via
`.rubocop.yml`
- Correct all missing descriptions

Add a comment to disable to the cop for every missing GraphQL
description. When folks backfill the description to satisfy the cop,
they can remove the line.

Since we are now including arguments, and (probably) enums,
this is just called GraphQL Descriptions unless it proves
to be confusing.

.rubocop.yml

@@ -275,8 +275,15 @@ RSpec/BeSuccessMatcher:
     - 'ee/spec/support/shared_examples/controllers/**/*'
     - 'spec/support/controllers/**/*'
     - 'ee/spec/support/controllers/**/*'
+
 Scalability/FileUploads:
   Enabled: true
   Include:
     - 'lib/api/**/*.rb'
     - 'ee/lib/api/**/*.rb'
+
+Graphql/Descriptions:
+  Enabled: true
+  Include:
+    - 'app/graphql/**/*'
+    - 'ee/app/graphql/**/*'

app/graphql/resolvers/echo_resolver.rb

@@ -2,7 +2,7 @@
 
 module Resolvers
   class EchoResolver < BaseResolver
-    argument    :text, GraphQL::STRING_TYPE, required: true
+    argument    :text, GraphQL::STRING_TYPE, required: true # rubocop:disable Graphql/Descriptions
     description 'Testing endpoint to validate the API with'
 
     def resolve(**args)

app/graphql/resolvers/issues_resolver.rb

@@ -33,9 +33,9 @@ module Resolvers
     argument :closed_after, Types::TimeType,
               required: false,
               description: "Issues closed after this date"
-    argument :search, GraphQL::STRING_TYPE,
+    argument :search, GraphQL::STRING_TYPE, # rubocop:disable Graphql/Descriptions
               required: false
-    argument :sort, Types::Sort,
+    argument :sort, Types::Sort, # rubocop:disable Graphql/Descriptions
               required: false,
               default_value: 'created_desc'
 

app/graphql/types/ci/detailed_status_type.rb

@@ -6,14 +6,14 @@ module Types
     class DetailedStatusType < BaseObject
       graphql_name 'DetailedStatus'
 
-      field :group, GraphQL::STRING_TYPE, null: false
-      field :icon, GraphQL::STRING_TYPE, null: false
-      field :favicon, GraphQL::STRING_TYPE, null: false
-      field :details_path, GraphQL::STRING_TYPE, null: false
-      field :has_details, GraphQL::BOOLEAN_TYPE, null: false, method: :has_details?
-      field :label, GraphQL::STRING_TYPE, null: false
-      field :text, GraphQL::STRING_TYPE, null: false
-      field :tooltip, GraphQL::STRING_TYPE, null: false, method: :status_tooltip
+      field :group, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :icon, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :favicon, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :details_path, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :has_details, GraphQL::BOOLEAN_TYPE, null: false, method: :has_details? # rubocop:disable Graphql/Descriptions
+      field :label, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :text, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :tooltip, GraphQL::STRING_TYPE, null: false, method: :status_tooltip # rubocop:disable Graphql/Descriptions
     end
     # rubocop: enable Graphql/AuthorizeTypes
   end

app/graphql/types/ci/pipeline_type.rb

@@ -9,13 +9,13 @@ module Types
 
       expose_permissions Types::PermissionTypes::Ci::Pipeline
 
-      field :id, GraphQL::ID_TYPE, null: false
-      field :iid, GraphQL::STRING_TYPE, null: false
+      field :id, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :iid, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-      field :sha, GraphQL::STRING_TYPE, null: false
-      field :before_sha, GraphQL::STRING_TYPE, null: true
-      field :status, PipelineStatusEnum, null: false
-      field :detailed_status,
+      field :sha, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :before_sha, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+      field :status, PipelineStatusEnum, null: false # rubocop:disable Graphql/Descriptions
+      field :detailed_status, # rubocop:disable Graphql/Descriptions
             Types::Ci::DetailedStatusType,
             null: false,
             resolve: -> (obj, _args, ctx) { obj.detailed_status(ctx[:current_user]) }
@@ -27,11 +27,11 @@ module Types
             GraphQL::FLOAT_TYPE,
             null: true,
             description: "Coverage percentage"
-      field :created_at, Types::TimeType, null: false
-      field :updated_at, Types::TimeType, null: false
-      field :started_at, Types::TimeType, null: true
-      field :finished_at, Types::TimeType, null: true
-      field :committed_at, Types::TimeType, null: true
+      field :created_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
+      field :updated_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
+      field :started_at, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
+      field :finished_at, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
+      field :committed_at, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
 
       # TODO: Add triggering user as a type
     end

app/graphql/types/commit_type.rb

@@ -8,16 +8,16 @@ module Types
 
     present_using CommitPresenter
 
-    field :id, type: GraphQL::ID_TYPE, null: false
-    field :sha, type: GraphQL::STRING_TYPE, null: false
-    field :title, type: GraphQL::STRING_TYPE, null: true
-    field :description, type: GraphQL::STRING_TYPE, null: true
-    field :message, type: GraphQL::STRING_TYPE, null: true
-    field :authored_date, type: Types::TimeType, null: true
-    field :web_url, type: GraphQL::STRING_TYPE, null: false
+    field :id, type: GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :sha, type: GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :title, type: GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :description, type: GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :message, type: GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :authored_date, type: Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
+    field :web_url, type: GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
     # models/commit lazy loads the author by email
-    field :author, type: Types::UserType, null: true
+    field :author, type: Types::UserType, null: true # rubocop:disable Graphql/Descriptions
 
     field :latest_pipeline,
           type: Types::Ci::PipelineType,

app/graphql/types/group_type.rb

@@ -8,13 +8,13 @@ module Types
 
     expose_permissions Types::PermissionTypes::Group
 
-    field :web_url, GraphQL::STRING_TYPE, null: false
+    field :web_url, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :avatar_url, GraphQL::STRING_TYPE, null: true, resolve: -> (group, args, ctx) do
+    field :avatar_url, GraphQL::STRING_TYPE, null: true, resolve: -> (group, args, ctx) do # rubocop:disable Graphql/Descriptions
       group.avatar_url(only_path: false)
     end
 
-    field :parent, GroupType,
+    field :parent, GroupType, # rubocop:disable Graphql/Descriptions
           null: true,
           resolve: -> (obj, _args, _ctx) { Gitlab::Graphql::Loaders::BatchModelLoader.new(Group, obj.parent_id).find }
   end

app/graphql/types/issue_type.rb

@@ -12,48 +12,48 @@ module Types
 
     present_using IssuePresenter
 
-    field :iid, GraphQL::ID_TYPE, null: false
-    field :title, GraphQL::STRING_TYPE, null: false
+    field :iid, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :title, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
     markdown_field :title_html, null: true
-    field :description, GraphQL::STRING_TYPE, null: true
+    field :description, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
     markdown_field :description_html, null: true
-    field :state, IssueStateEnum, null: false
+    field :state, IssueStateEnum, null: false # rubocop:disable Graphql/Descriptions
 
-    field :reference, GraphQL::STRING_TYPE, null: false, method: :to_reference do
-      argument :full, GraphQL::BOOLEAN_TYPE, required: false, default_value: false
+    field :reference, GraphQL::STRING_TYPE, null: false, method: :to_reference do # rubocop:disable Graphql/Descriptions
+      argument :full, GraphQL::BOOLEAN_TYPE, required: false, default_value: false # rubocop:disable Graphql/Descriptions
     end
 
-    field :author, Types::UserType,
+    field :author, Types::UserType, # rubocop:disable Graphql/Descriptions
           null: false,
           resolve: -> (obj, _args, _ctx) { Gitlab::Graphql::Loaders::BatchModelLoader.new(User, obj.author_id).find }
 
     # Remove complexity when BatchLoader is used
-    field :assignees, Types::UserType.connection_type, null: true, complexity: 5
+    field :assignees, Types::UserType.connection_type, null: true, complexity: 5 # rubocop:disable Graphql/Descriptions
 
     # Remove complexity when BatchLoader is used
-    field :labels, Types::LabelType.connection_type, null: true, complexity: 5
-    field :milestone, Types::MilestoneType,
+    field :labels, Types::LabelType.connection_type, null: true, complexity: 5 # rubocop:disable Graphql/Descriptions
+    field :milestone, Types::MilestoneType, # rubocop:disable Graphql/Descriptions
           null: true,
           resolve: -> (obj, _args, _ctx) { Gitlab::Graphql::Loaders::BatchModelLoader.new(Milestone, obj.milestone_id).find }
 
-    field :due_date, Types::TimeType, null: true
-    field :confidential, GraphQL::BOOLEAN_TYPE, null: false
-    field :discussion_locked, GraphQL::BOOLEAN_TYPE,
+    field :due_date, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
+    field :confidential, GraphQL::BOOLEAN_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :discussion_locked, GraphQL::BOOLEAN_TYPE, # rubocop:disable Graphql/Descriptions
           null: false,
           resolve: -> (obj, _args, _ctx) { !!obj.discussion_locked }
 
-    field :upvotes, GraphQL::INT_TYPE, null: false
-    field :downvotes, GraphQL::INT_TYPE, null: false
-    field :user_notes_count, GraphQL::INT_TYPE, null: false
-    field :web_path, GraphQL::STRING_TYPE, null: false, method: :issue_path
-    field :web_url, GraphQL::STRING_TYPE, null: false
-    field :relative_position, GraphQL::INT_TYPE, null: true
+    field :upvotes, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :downvotes, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :user_notes_count, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :web_path, GraphQL::STRING_TYPE, null: false, method: :issue_path # rubocop:disable Graphql/Descriptions
+    field :web_url, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :relative_position, GraphQL::INT_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :closed_at, Types::TimeType, null: true
+    field :closed_at, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
 
-    field :created_at, Types::TimeType, null: false
-    field :updated_at, Types::TimeType, null: false
+    field :created_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
+    field :updated_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
 
-    field :task_completion_status, Types::TaskCompletionStatus, null: false
+    field :task_completion_status, Types::TaskCompletionStatus, null: false # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/label_type.rb

@@ -6,10 +6,10 @@ module Types
 
     authorize :read_label
 
-    field :description, GraphQL::STRING_TYPE, null: true
+    field :description, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
     markdown_field :description_html, null: true
-    field :title, GraphQL::STRING_TYPE, null: false
-    field :color, GraphQL::STRING_TYPE, null: false
-    field :text_color, GraphQL::STRING_TYPE, null: false
+    field :title, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :color, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :text_color, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/merge_request_type.rb

@@ -12,53 +12,55 @@ module Types
 
     present_using MergeRequestPresenter
 
-    field :id, GraphQL::ID_TYPE, null: false
-    field :iid, GraphQL::STRING_TYPE, null: false
-    field :title, GraphQL::STRING_TYPE, null: false
+    field :id, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :iid, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :title, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
     markdown_field :title_html, null: true
-    field :description, GraphQL::STRING_TYPE, null: true
+    field :description, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
     markdown_field :description_html, null: true
-    field :state, MergeRequestStateEnum, null: false
-    field :created_at, Types::TimeType, null: false
-    field :updated_at, Types::TimeType, null: false
-    field :source_project, Types::ProjectType, null: true
-    field :target_project, Types::ProjectType, null: false
-    field :diff_refs, Types::DiffRefsType, null: true
+    field :state, MergeRequestStateEnum, null: false # rubocop:disable Graphql/Descriptions
+    field :created_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
+    field :updated_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
+    field :source_project, Types::ProjectType, null: true # rubocop:disable Graphql/Descriptions
+    field :target_project, Types::ProjectType, null: false # rubocop:disable Graphql/Descriptions
+    field :diff_refs, Types::DiffRefsType, null: true # rubocop:disable Graphql/Descriptions
     # Alias for target_project
-    field :project, Types::ProjectType, null: false
-    field :project_id, GraphQL::INT_TYPE, null: false, method: :target_project_id
-    field :source_project_id, GraphQL::INT_TYPE, null: true
-    field :target_project_id, GraphQL::INT_TYPE, null: false
-    field :source_branch, GraphQL::STRING_TYPE, null: false
-    field :target_branch, GraphQL::STRING_TYPE, null: false
-    field :work_in_progress, GraphQL::BOOLEAN_TYPE, method: :work_in_progress?, null: false
-    field :merge_when_pipeline_succeeds, GraphQL::BOOLEAN_TYPE, null: true
-    field :diff_head_sha, GraphQL::STRING_TYPE, null: true
-    field :merge_commit_sha, GraphQL::STRING_TYPE, null: true
-    field :user_notes_count, GraphQL::INT_TYPE, null: true
-    field :should_remove_source_branch, GraphQL::BOOLEAN_TYPE, method: :should_remove_source_branch?, null: true
-    field :force_remove_source_branch, GraphQL::BOOLEAN_TYPE, method: :force_remove_source_branch?, null: true
-    field :merge_status, GraphQL::STRING_TYPE, null: true
-    field :in_progress_merge_commit_sha, GraphQL::STRING_TYPE, null: true
-    field :merge_error, GraphQL::STRING_TYPE, null: true
-    field :allow_collaboration, GraphQL::BOOLEAN_TYPE, null: true
-    field :should_be_rebased, GraphQL::BOOLEAN_TYPE, method: :should_be_rebased?, null: false
-    field :rebase_commit_sha, GraphQL::STRING_TYPE, null: true
-    field :rebase_in_progress, GraphQL::BOOLEAN_TYPE, method: :rebase_in_progress?, null: false, calls_gitaly: true
+    field :project, Types::ProjectType, null: false # rubocop:disable Graphql/Descriptions
+    field :project_id, GraphQL::INT_TYPE, null: false, method: :target_project_id # rubocop:disable Graphql/Descriptions
+    field :source_project_id, GraphQL::INT_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :target_project_id, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :source_branch, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :target_branch, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :work_in_progress, GraphQL::BOOLEAN_TYPE, method: :work_in_progress?, null: false # rubocop:disable Graphql/Descriptions
+    field :merge_when_pipeline_succeeds, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :diff_head_sha, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :merge_commit_sha, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :user_notes_count, GraphQL::INT_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :should_remove_source_branch, GraphQL::BOOLEAN_TYPE, method: :should_remove_source_branch?, null: true # rubocop:disable Graphql/Descriptions
+    field :force_remove_source_branch, GraphQL::BOOLEAN_TYPE, method: :force_remove_source_branch?, null: true # rubocop:disable Graphql/Descriptions
+    field :merge_status, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :in_progress_merge_commit_sha, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :merge_error, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :allow_collaboration, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :should_be_rebased, GraphQL::BOOLEAN_TYPE, method: :should_be_rebased?, null: false # rubocop:disable Graphql/Descriptions
+    field :rebase_commit_sha, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :rebase_in_progress, GraphQL::BOOLEAN_TYPE, method: :rebase_in_progress?, null: false, calls_gitaly: true # rubocop:disable Graphql/Descriptions
+    # rubocop:disable Graphql/Descriptions
     field :merge_commit_message, GraphQL::STRING_TYPE, method: :default_merge_commit_message, null: true, deprecation_reason: "Renamed to defaultMergeCommitMessage"
-    field :default_merge_commit_message, GraphQL::STRING_TYPE, null: true
-    field :merge_ongoing, GraphQL::BOOLEAN_TYPE, method: :merge_ongoing?, null: false
-    field :source_branch_exists, GraphQL::BOOLEAN_TYPE, method: :source_branch_exists?, null: false
-    field :mergeable_discussions_state, GraphQL::BOOLEAN_TYPE, null: true
-    field :web_url, GraphQL::STRING_TYPE, null: true
-    field :upvotes, GraphQL::INT_TYPE, null: false
-    field :downvotes, GraphQL::INT_TYPE, null: false
-    field :subscribed, GraphQL::BOOLEAN_TYPE, method: :subscribed?, null: false
+    # rubocop:enable Graphql/Descriptions
+    field :default_merge_commit_message, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :merge_ongoing, GraphQL::BOOLEAN_TYPE, method: :merge_ongoing?, null: false # rubocop:disable Graphql/Descriptions
+    field :source_branch_exists, GraphQL::BOOLEAN_TYPE, method: :source_branch_exists?, null: false # rubocop:disable Graphql/Descriptions
+    field :mergeable_discussions_state, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :web_url, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :upvotes, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :downvotes, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :subscribed, GraphQL::BOOLEAN_TYPE, method: :subscribed?, null: false # rubocop:disable Graphql/Descriptions
 
-    field :head_pipeline, Types::Ci::PipelineType, null: true, method: :actual_head_pipeline
-    field :pipelines, Types::Ci::PipelineType.connection_type,
+    field :head_pipeline, Types::Ci::PipelineType, null: true, method: :actual_head_pipeline # rubocop:disable Graphql/Descriptions
+    field :pipelines, Types::Ci::PipelineType.connection_type, # rubocop:disable Graphql/Descriptions
           resolver: Resolvers::MergeRequestPipelinesResolver
 
-    field :task_completion_status, Types::TaskCompletionStatus, null: false
+    field :task_completion_status, Types::TaskCompletionStatus, null: false # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/metadata_type.rb

@@ -6,7 +6,7 @@ module Types
 
     authorize :read_instance_metadata
 
-    field :version, GraphQL::STRING_TYPE, null: false
-    field :revision, GraphQL::STRING_TYPE, null: false
+    field :version, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :revision, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/milestone_type.rb

@@ -6,14 +6,14 @@ module Types
 
     authorize :read_milestone
 
-    field :description, GraphQL::STRING_TYPE, null: true
-    field :title, GraphQL::STRING_TYPE, null: false
-    field :state, GraphQL::STRING_TYPE, null: false
+    field :description, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :title, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :state, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :due_date, Types::TimeType, null: true
-    field :start_date, Types::TimeType, null: true
+    field :due_date, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
+    field :start_date, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
 
-    field :created_at, Types::TimeType, null: false
-    field :updated_at, Types::TimeType, null: false
+    field :created_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
+    field :updated_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/namespace_type.rb

@@ -6,25 +6,25 @@ module Types
 
     authorize :read_namespace
 
-    field :id, GraphQL::ID_TYPE, null: false
+    field :id, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :name, GraphQL::STRING_TYPE, null: false
-    field :path, GraphQL::STRING_TYPE, null: false
-    field :full_name, GraphQL::STRING_TYPE, null: false
-    field :full_path, GraphQL::ID_TYPE, null: false
+    field :name, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :path, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :full_name, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :full_path, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :description, GraphQL::STRING_TYPE, null: true
+    field :description, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
     markdown_field :description_html, null: true
-    field :visibility, GraphQL::STRING_TYPE, null: true
-    field :lfs_enabled, GraphQL::BOOLEAN_TYPE, null: true, method: :lfs_enabled?
-    field :request_access_enabled, GraphQL::BOOLEAN_TYPE, null: true
+    field :visibility, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :lfs_enabled, GraphQL::BOOLEAN_TYPE, null: true, method: :lfs_enabled? # rubocop:disable Graphql/Descriptions
+    field :request_access_enabled, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
     field :root_storage_statistics, Types::RootStorageStatisticsType,
           null: true,
           description: 'The aggregated storage statistics. Only available for root namespaces',
           resolve: -> (obj, _args, _ctx) { Gitlab::Graphql::Loaders::BatchRootStorageStatisticsLoader.new(obj.id).find }
 
-    field :projects,
+    field :projects, # rubocop:disable Graphql/Descriptions
           Types::ProjectType.connection_type,
           null: false,
           resolver: ::Resolvers::NamespaceProjectsResolver

app/graphql/types/notes/diff_position_type.rb

@@ -7,7 +7,7 @@ module Types
     class DiffPositionType < BaseObject
       graphql_name 'DiffPosition'
 
-      field :diff_refs, Types::DiffRefsType, null: false
+      field :diff_refs, Types::DiffRefsType, null: false # rubocop:disable Graphql/Descriptions
 
       field :file_path, GraphQL::STRING_TYPE, null: false,
             description: "The path of the file that was changed"
@@ -15,7 +15,7 @@ module Types
             description: "The path of the file on the start sha."
       field :new_path, GraphQL::STRING_TYPE, null: true,
             description: "The path of the file on the head sha."
-      field :position_type, Types::Notes::PositionTypeEnum, null: false
+      field :position_type, Types::Notes::PositionTypeEnum, null: false # rubocop:disable Graphql/Descriptions
 
       # Fields for text positions
       field :old_line, GraphQL::INT_TYPE, null: true,

app/graphql/types/notes/discussion_type.rb

@@ -7,9 +7,9 @@ module Types
 
       authorize :read_note
 
-      field :id, GraphQL::ID_TYPE, null: false
+      field :id, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
       field :reply_id, GraphQL::ID_TYPE, null: false, description: 'The ID used to reply to this discussion'
-      field :created_at, Types::TimeType, null: false
+      field :created_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
       field :notes, Types::Notes::NoteType.connection_type, null: false, description: "All notes in the discussion"
 
       # The gem we use to generate Global IDs is hard-coded to work with

app/graphql/types/notes/note_type.rb

@@ -9,7 +9,7 @@ module Types
 
       expose_permissions Types::PermissionTypes::Note
 
-      field :id, GraphQL::ID_TYPE, null: false
+      field :id, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
       field :project, Types::ProjectType,
             null: true,
@@ -37,10 +37,10 @@ module Types
 
       markdown_field :body_html, null: true, method: :note
 
-      field :created_at, Types::TimeType, null: false
-      field :updated_at, Types::TimeType, null: false
+      field :created_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
+      field :updated_at, Types::TimeType, null: false # rubocop:disable Graphql/Descriptions
       field :discussion, Types::Notes::DiscussionType, null: true, description: "The discussion this note is a part of"
-      field :resolvable, GraphQL::BOOLEAN_TYPE, null: false, method: :resolvable?
+      field :resolvable, GraphQL::BOOLEAN_TYPE, null: false, method: :resolvable? # rubocop:disable Graphql/Descriptions
       field :resolved_at, Types::TimeType, null: true, description: "The time the discussion was resolved"
       field :position, Types::Notes::DiffPositionType, null: true, description: "The position of this note on a diff"
     end

app/graphql/types/permission_types/base_permission_type.rb

@@ -28,7 +28,7 @@ module Types
           description: "Whether or not a user can perform `#{name}` on this resource",
           null: false)
 
-        field(**kword_args)
+        field(**kword_args) # rubocop:disable Graphql/Descriptions
       end
 
       def self.resolving_keywords?(arguments)

app/graphql/types/project_statistics_type.rb

@@ -6,13 +6,13 @@ module Types
 
     authorize :read_statistics
 
-    field :commit_count, GraphQL::INT_TYPE, null: false
+    field :commit_count, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :storage_size, GraphQL::INT_TYPE, null: false
-    field :repository_size, GraphQL::INT_TYPE, null: false
-    field :lfs_objects_size, GraphQL::INT_TYPE, null: false
-    field :build_artifacts_size, GraphQL::INT_TYPE, null: false
-    field :packages_size, GraphQL::INT_TYPE, null: false
-    field :wiki_size, GraphQL::INT_TYPE, null: true
+    field :storage_size, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :repository_size, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :lfs_objects_size, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :build_artifacts_size, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :packages_size, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :wiki_size, GraphQL::INT_TYPE, null: true # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/project_type.rb

@@ -8,95 +8,95 @@ module Types
 
     expose_permissions Types::PermissionTypes::Project
 
-    field :id, GraphQL::ID_TYPE, null: false
+    field :id, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :full_path, GraphQL::ID_TYPE, null: false
-    field :path, GraphQL::STRING_TYPE, null: false
+    field :full_path, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :path, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :name_with_namespace, GraphQL::STRING_TYPE, null: false
-    field :name, GraphQL::STRING_TYPE, null: false
+    field :name_with_namespace, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :name, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
 
-    field :description, GraphQL::STRING_TYPE, null: true
+    field :description, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
     markdown_field :description_html, null: true
 
-    field :tag_list, GraphQL::STRING_TYPE, null: true
+    field :tag_list, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :ssh_url_to_repo, GraphQL::STRING_TYPE, null: true
-    field :http_url_to_repo, GraphQL::STRING_TYPE, null: true
-    field :web_url, GraphQL::STRING_TYPE, null: true
+    field :ssh_url_to_repo, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :http_url_to_repo, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :web_url, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :star_count, GraphQL::INT_TYPE, null: false
-    field :forks_count, GraphQL::INT_TYPE, null: false, calls_gitaly: true # 4 times
+    field :star_count, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :forks_count, GraphQL::INT_TYPE, null: false, calls_gitaly: true # 4 times # rubocop:disable Graphql/Descriptions
 
-    field :created_at, Types::TimeType, null: true
-    field :last_activity_at, Types::TimeType, null: true
+    field :created_at, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
+    field :last_activity_at, Types::TimeType, null: true # rubocop:disable Graphql/Descriptions
 
-    field :archived, GraphQL::BOOLEAN_TYPE, null: true
+    field :archived, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :visibility, GraphQL::STRING_TYPE, null: true
+    field :visibility, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :container_registry_enabled, GraphQL::BOOLEAN_TYPE, null: true
-    field :shared_runners_enabled, GraphQL::BOOLEAN_TYPE, null: true
-    field :lfs_enabled, GraphQL::BOOLEAN_TYPE, null: true
-    field :merge_requests_ff_only_enabled, GraphQL::BOOLEAN_TYPE, null: true
+    field :container_registry_enabled, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :shared_runners_enabled, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :lfs_enabled, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :merge_requests_ff_only_enabled, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :avatar_url, GraphQL::STRING_TYPE, null: true, calls_gitaly: true, resolve: -> (project, args, ctx) do
+    field :avatar_url, GraphQL::STRING_TYPE, null: true, calls_gitaly: true, resolve: -> (project, args, ctx) do # rubocop:disable Graphql/Descriptions
       project.avatar_url(only_path: false)
     end
 
     %i[issues merge_requests wiki snippets].each do |feature|
-      field "#{feature}_enabled", GraphQL::BOOLEAN_TYPE, null: true, resolve: -> (project, args, ctx) do
+      field "#{feature}_enabled", GraphQL::BOOLEAN_TYPE, null: true, resolve: -> (project, args, ctx) do # rubocop:disable Graphql/Descriptions
         project.feature_available?(feature, ctx[:current_user])
       end
     end
 
-    field :jobs_enabled, GraphQL::BOOLEAN_TYPE, null: true, resolve: -> (project, args, ctx) do
+    field :jobs_enabled, GraphQL::BOOLEAN_TYPE, null: true, resolve: -> (project, args, ctx) do # rubocop:disable Graphql/Descriptions
       project.feature_available?(:builds, ctx[:current_user])
     end
 
-    field :public_jobs, GraphQL::BOOLEAN_TYPE, method: :public_builds, null: true
+    field :public_jobs, GraphQL::BOOLEAN_TYPE, method: :public_builds, null: true # rubocop:disable Graphql/Descriptions
 
-    field :open_issues_count, GraphQL::INT_TYPE, null: true, resolve: -> (project, args, ctx) do
+    field :open_issues_count, GraphQL::INT_TYPE, null: true, resolve: -> (project, args, ctx) do # rubocop:disable Graphql/Descriptions
       project.open_issues_count if project.feature_available?(:issues, ctx[:current_user])
     end
 
-    field :import_status, GraphQL::STRING_TYPE, null: true
+    field :import_status, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :only_allow_merge_if_pipeline_succeeds, GraphQL::BOOLEAN_TYPE, null: true
-    field :request_access_enabled, GraphQL::BOOLEAN_TYPE, null: true
-    field :only_allow_merge_if_all_discussions_are_resolved, GraphQL::BOOLEAN_TYPE, null: true
-    field :printing_merge_request_link_enabled, GraphQL::BOOLEAN_TYPE, null: true
+    field :only_allow_merge_if_pipeline_succeeds, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :request_access_enabled, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :only_allow_merge_if_all_discussions_are_resolved, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
+    field :printing_merge_request_link_enabled, GraphQL::BOOLEAN_TYPE, null: true # rubocop:disable Graphql/Descriptions
 
-    field :namespace, Types::NamespaceType, null: true
-    field :group, Types::GroupType, null: true
+    field :namespace, Types::NamespaceType, null: true # rubocop:disable Graphql/Descriptions
+    field :group, Types::GroupType, null: true # rubocop:disable Graphql/Descriptions
 
-    field :statistics, Types::ProjectStatisticsType,
+    field :statistics, Types::ProjectStatisticsType, # rubocop:disable Graphql/Descriptions
           null: true,
           resolve: -> (obj, _args, _ctx) { Gitlab::Graphql::Loaders::BatchProjectStatisticsLoader.new(obj.id).find }
 
-    field :repository, Types::RepositoryType, null: true
+    field :repository, Types::RepositoryType, null: true # rubocop:disable Graphql/Descriptions
 
-    field :merge_requests,
+    field :merge_requests, # rubocop:disable Graphql/Descriptions
           Types::MergeRequestType.connection_type,
           null: true,
           resolver: Resolvers::MergeRequestsResolver
 
-    field :merge_request,
+    field :merge_request, # rubocop:disable Graphql/Descriptions
           Types::MergeRequestType,
           null: true,
           resolver: Resolvers::MergeRequestsResolver.single
 
-    field :issues,
+    field :issues, # rubocop:disable Graphql/Descriptions
           Types::IssueType.connection_type,
           null: true,
           resolver: Resolvers::IssuesResolver
 
-    field :issue,
+    field :issue, # rubocop:disable Graphql/Descriptions
           Types::IssueType,
           null: true,
           resolver: Resolvers::IssuesResolver.single
 
-    field :pipelines,
+    field :pipelines, # rubocop:disable Graphql/Descriptions
           Types::Ci::PipelineType.connection_type,
           null: true,
           resolver: Resolvers::ProjectPipelinesResolver

app/graphql/types/query_type.rb

@@ -24,6 +24,6 @@ module Types
           resolver: Resolvers::MetadataResolver,
           description: 'Metadata about GitLab'
 
-    field :echo, GraphQL::STRING_TYPE, null: false, resolver: Resolvers::EchoResolver
+    field :echo, GraphQL::STRING_TYPE, null: false, resolver: Resolvers::EchoResolver # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/repository_type.rb

@@ -6,9 +6,9 @@ module Types
 
     authorize :download_code
 
-    field :root_ref, GraphQL::STRING_TYPE, null: true, calls_gitaly: true
-    field :empty, GraphQL::BOOLEAN_TYPE, null: false, method: :empty?, calls_gitaly: true
-    field :exists, GraphQL::BOOLEAN_TYPE, null: false, method: :exists?
-    field :tree, Types::Tree::TreeType, null: true, resolver: Resolvers::TreeResolver, calls_gitaly: true
+    field :root_ref, GraphQL::STRING_TYPE, null: true, calls_gitaly: true # rubocop:disable Graphql/Descriptions
+    field :empty, GraphQL::BOOLEAN_TYPE, null: false, method: :empty?, calls_gitaly: true # rubocop:disable Graphql/Descriptions
+    field :exists, GraphQL::BOOLEAN_TYPE, null: false, method: :exists? # rubocop:disable Graphql/Descriptions
+    field :tree, Types::Tree::TreeType, null: true, resolver: Resolvers::TreeResolver, calls_gitaly: true # rubocop:disable Graphql/Descriptions
   end
 end

app/graphql/types/task_completion_status.rb

@@ -8,8 +8,8 @@ module Types
     graphql_name 'TaskCompletionStatus'
     description 'Completion status of tasks'
 
-    field :count, GraphQL::INT_TYPE, null: false
-    field :completed_count, GraphQL::INT_TYPE, null: false
+    field :count, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :completed_count, GraphQL::INT_TYPE, null: false # rubocop:disable Graphql/Descriptions
   end
   # rubocop: enable Graphql/AuthorizeTypes
 end

app/graphql/types/tree/blob_type.rb

@@ -10,8 +10,8 @@ module Types
 
       graphql_name 'Blob'
 
-      field :web_url, GraphQL::STRING_TYPE, null: true
-      field :lfs_oid, GraphQL::STRING_TYPE, null: true, resolve: -> (blob, args, ctx) do
+      field :web_url, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+      field :lfs_oid, GraphQL::STRING_TYPE, null: true, resolve: -> (blob, args, ctx) do # rubocop:disable Graphql/Descriptions
         Gitlab::Graphql::Loaders::BatchLfsOidLoader.new(blob.repository, blob.id).find
       end
       # rubocop: enable Graphql/AuthorizeTypes

app/graphql/types/tree/entry_type.rb

@@ -4,11 +4,11 @@ module Types
     module EntryType
       include Types::BaseInterface
 
-      field :id, GraphQL::ID_TYPE, null: false
-      field :name, GraphQL::STRING_TYPE, null: false
-      field :type, Tree::TypeEnum, null: false
-      field :path, GraphQL::STRING_TYPE, null: false
-      field :flat_path, GraphQL::STRING_TYPE, null: false
+      field :id, GraphQL::ID_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :name, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :type, Tree::TypeEnum, null: false # rubocop:disable Graphql/Descriptions
+      field :path, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+      field :flat_path, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
     end
   end
 end

app/graphql/types/tree/submodule_type.rb

@@ -8,8 +8,8 @@ module Types
 
       graphql_name 'Submodule'
 
-      field :web_url, type: GraphQL::STRING_TYPE, null: true
-      field :tree_url, type: GraphQL::STRING_TYPE, null: true
+      field :web_url, type: GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
+      field :tree_url, type: GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
     end
     # rubocop: enable Graphql/AuthorizeTypes
   end

app/graphql/types/tree/tree_entry_type.rb

@@ -11,7 +11,7 @@ module Types
       graphql_name 'TreeEntry'
       description 'Represents a directory'
 
-      field :web_url, GraphQL::STRING_TYPE, null: true
+      field :web_url, GraphQL::STRING_TYPE, null: true # rubocop:disable Graphql/Descriptions
     end
     # rubocop: enable Graphql/AuthorizeTypes
   end

app/graphql/types/tree/tree_type.rb

@@ -7,19 +7,21 @@ module Types
       graphql_name 'Tree'
 
       # Complexity 10 as it triggers a Gitaly call on each render
-      field :last_commit, Types::CommitType, null: true, complexity: 10, calls_gitaly: true, resolve: -> (tree, args, ctx) do
+      field :last_commit, Types::CommitType, null: true, complexity: 10, calls_gitaly: true, resolve: -> (tree, args, ctx) do # rubocop:disable Graphql/Descriptions
         tree.repository.last_commit_for_path(tree.sha, tree.path)
       end
 
-      field :trees, Types::Tree::TreeEntryType.connection_type, null: false, resolve: -> (obj, args, ctx) do
+      field :trees, Types::Tree::TreeEntryType.connection_type, null: false, resolve: -> (obj, args, ctx) do # rubocop:disable Graphql/Descriptions
         Gitlab::Graphql::Representation::TreeEntry.decorate(obj.trees, obj.repository)
       end
 
+      # rubocop:disable Graphql/Descriptions
       field :submodules, Types::Tree::SubmoduleType.connection_type, null: false, calls_gitaly: true, resolve: -> (obj, args, ctx) do
         Gitlab::Graphql::Representation::SubmoduleTreeEntry.decorate(obj.submodules, obj)
       end
+      # rubocop:enable Graphql/Descriptions
 
-      field :blobs, Types::Tree::BlobType.connection_type, null: false, calls_gitaly: true, resolve: -> (obj, args, ctx) do
+      field :blobs, Types::Tree::BlobType.connection_type, null: false, calls_gitaly: true, resolve: -> (obj, args, ctx) do # rubocop:disable Graphql/Descriptions
         Gitlab::Graphql::Representation::TreeEntry.decorate(obj.blobs, obj.repository)
       end
       # rubocop: enable Graphql/AuthorizeTypes

app/graphql/types/user_type.rb

@@ -8,9 +8,9 @@ module Types
 
     present_using UserPresenter
 
-    field :name, GraphQL::STRING_TYPE, null: false
-    field :username, GraphQL::STRING_TYPE, null: false
-    field :avatar_url, GraphQL::STRING_TYPE, null: false
-    field :web_url, GraphQL::STRING_TYPE, null: false
+    field :name, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :username, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :avatar_url, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
+    field :web_url, GraphQL::STRING_TYPE, null: false # rubocop:disable Graphql/Descriptions
   end
 end

rubocop/cop/graphql/authorize_types.rb

@@ -7,12 +7,12 @@ module RuboCop
         MSG = 'Add an `authorize :ability` call to the type: '\
               'https://docs.gitlab.com/ee/development/api_graphql_styleguide.html#type-authorization'
 
-        TYPES_DIR = 'app/graphql/types'
-
         # We want to exclude our own basetypes and scalars
         WHITELISTED_TYPES = %w[BaseEnum BaseScalar BasePermissionType MutationType
                                QueryType GraphQL::Schema BaseUnion].freeze
 
+        TYPES_DIR = 'app/graphql/types'
+
         def_node_search :authorize?, <<~PATTERN
           (send nil? :authorize ...)
         PATTERN
@@ -44,7 +44,7 @@ module RuboCop
         end
 
         def superclass_constant(class_node)
-          # First one is the class name itself, second is it's superclass
+          # First one is the class name itself, second is its superclass
           _class_constant, *others = class_node.descendants
 
           others.find { |node| node.const_type? && node&.const_name != 'Types' }

rubocop/cop/graphql/descriptions.rb

+# frozen_string_literal: true
+
+# This cop checks for missing GraphQL field descriptions.
+#
+# @example
+#
+#   # bad
+#   class AwfulClass
+#     field :some_field, GraphQL::STRING_TYPE
+#   end
+#
+#   class TerribleClass
+#     argument :some_argument, GraphQL::STRING_TYPE
+#   end
+#
+#   # good
+#   class GreatClass
+#     argument :some_field,
+#       GraphQL::STRING_TYPE,
+#       description: "Well described - a superb description"
+#
+#     field :some_field,
+#       GraphQL::STRING_TYPE,
+#       description: "A thorough and compelling description"
+#   end
+
+module RuboCop
+  module Cop
+    module Graphql
+      class Descriptions < RuboCop::Cop::Cop
+        MSG = 'Please add a `description` property.'
+
+        # ability_field and permission_field set a default description.
+        def_node_matcher :fields, <<~PATTERN
+          (send nil? :field $...)
+        PATTERN
+
+        def_node_matcher :arguments, <<~PATTERN
+          (send nil? :argument $...)
+        PATTERN
+
+        def_node_matcher :has_description?, <<~PATTERN
+          (hash <(pair (sym :description) _) ...>)
+        PATTERN
+
+        def on_send(node)
+          matches = fields(node) || arguments(node)
+
+          return if matches.nil?
+
+          add_offense(node, location: :expression) unless has_description?(matches.last)
+        end
+      end
+    end
+  end
+end

rubocop/graphql_helpers.rb

+# frozen_string_literal: true
+
+module RuboCop
+  module GraphqlHelpers
+    TYPES_DIR = 'app/graphql/types'
+
+    def in_type?(node)
+      path = node.location.expression.source_buffer.name
+
+      path.include?(TYPES_DIR)
+    end
+  end
+end

rubocop/rubocop.rb

@@ -49,3 +49,4 @@ require_relative 'cop/code_reuse/active_record'
 require_relative 'cop/group_public_or_visible_to_user'
 require_relative 'cop/inject_enterprise_edition_module'
 require_relative 'cop/graphql/authorize_types'
+require_relative 'cop/graphql/descriptions'

spec/rubocop/cop/graphql/descriptions_spec.rb

+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../../rubocop/cop/graphql/descriptions'
+
+describe RuboCop::Cop::Graphql::Descriptions do
+  include RuboCop::RSpec::ExpectOffense
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  context 'fields' do
+    it 'adds an offense when there is no field description' do
+      inspect_source(<<~TYPE)
+        module Types
+          class FakeType < BaseObject
+            field :a_thing,
+              GraphQL::STRING_TYPE,
+              null: false
+          end
+        end
+      TYPE
+
+      expect(cop.offenses.size).to eq 1
+    end
+
+    it 'does not add an offense for fields with a description' do
+      expect_no_offenses(<<~TYPE.strip)
+        module Types
+          class FakeType < BaseObject
+            graphql_name 'FakeTypeName'
+
+            argument :a_thing,
+              GraphQL::STRING_TYPE,
+              null: false,
+              description: 'A descriptive description'
+          end
+        end
+      TYPE
+    end
+  end
+
+  context 'arguments' do
+    it 'adds an offense when there is no argument description' do
+      inspect_source(<<~TYPE)
+        module Types
+          class FakeType < BaseObject
+            argument :a_thing,
+              GraphQL::STRING_TYPE,
+              null: false
+          end
+        end
+      TYPE
+
+      expect(cop.offenses.size).to eq 1
+    end
+
+    it 'does not add an offense for arguments with a description' do
+      expect_no_offenses(<<~TYPE.strip)
+        module Types
+          class FakeType < BaseObject
+            graphql_name 'FakeTypeName'
+
+            argument :a_thing,
+              GraphQL::STRING_TYPE,
+              null: false,
+              description: 'Behold! A description'
+          end
+        end
+      TYPE
+    end
+  end
+end