feat: ability to send communication emails in plain text

app/api/communication_rules_api.rb

@@ -690,6 +690,7 @@ def sync_set_schedules!(communication_set, raw_schedules)
       requires :type, type: String
       optional :subject, type: String
       optional :body, type: String
+      optional :plain_text, type: Boolean
       optional :email_tutors, type: Boolean
       optional :email_convenors, type: Boolean
       optional :target_grade, type: Integer
@@ -710,6 +711,7 @@ def sync_set_schedules!(communication_set, raw_schedules)
                                                   :type,
                                                   :subject,
                                                   :body,
+                                                  :plain_text,
                                                   :email_tutors,
                                                   :email_convenors,
                                                   :target_grade,
@@ -729,6 +731,7 @@ def sync_set_schedules!(communication_set, raw_schedules)
       optional :type, type: String
       optional :subject, type: String
       optional :body, type: String
+      optional :plain_text, type: Boolean
       optional :email_tutors, type: Boolean
       optional :email_convenors, type: Boolean
       optional :target_grade, type: Integer
@@ -746,7 +749,7 @@ def sync_set_schedules!(communication_set, raw_schedules)
     action = rule.communication_actions.find(params[:id])
     action_params = ActionController::Parameters.new(params)
                                                 .require(:communication_action)
-                                                .permit(:type, :subject, :body, :email_tutors, :email_convenors, :target_grade, :task_definition_id)
+                                                .permit(:type, :subject, :body, :plain_text, :email_tutors, :email_convenors, :target_grade, :task_definition_id)
 
     action.update!(action_params)
     present action, with: Entities::CommunicationActionEntity

app/api/entities/communication_action_entity.rb

@@ -5,6 +5,7 @@ class CommunicationActionEntity < Grape::Entity
     expose :communication_rule_id
     expose :subject
     expose :body
+    expose :plain_text
     expose :email_tutors
     expose :email_convenors
     expose :target_grade

app/mailers/communications_mailer.rb

@@ -1,9 +1,14 @@
 class CommunicationsMailer < ApplicationMailer
-  def communication_email(to:, from:, subject:, body:, recipient:, sender:, unit:, rule:)
+  def communication_email(to:, from:, subject:, body:, recipient:, sender:, plain_text: false)
+    if plain_text
+      @body = body.to_s
+      return mail(to: to, from: from, subject: subject) do |format|
+        format.text { render plain: @body }
+      end
+    end
+
     @recipient = recipient
     @sender = sender
-    @unit = unit
-    @rule = rule
     @body = body.to_s
     @body_paragraphs = @body.split(/\r?\n/).map(&:strip).reject(&:blank?)
 

app/services/communication_transfer.rb

@@ -19,7 +19,7 @@ class InvalidDocument < StandardError; end
     type operator target_grade task_statuses task_status_count task_target_grade
     activity_days spec_con_days submitted_portfolio
   ].freeze
-  ACTION_ATTRIBUTES = %w[type subject body email_tutors email_convenors target_grade].freeze
+  ACTION_ATTRIBUTES = %w[type subject body plain_text email_tutors email_convenors target_grade].freeze
 
   # Abbreviated references. Campuses are shared between units; everything else
   # is unit scoped. Group sets and groups are named rather than abbreviated, so

app/sidekiq/execute_communication_set_job.rb

@@ -164,10 +164,9 @@ def execute_email_student_action(action, projects, unit, rule)
         from: sender,
         subject: subject,
         body: body,
+        plain_text: action.plain_text,
         recipient: recipient,
-        sender: sender_user_for(unit),
-        unit: unit,
-        rule: rule
+        sender: sender_user_for(unit)
       ).deliver_now
 
       {
@@ -205,10 +204,9 @@ def execute_email_staff_action(action, projects, unit, rule)
           from: sender,
           subject: subject,
           body: body,
+          plain_text: action.plain_text,
           recipient: recipient,
-          sender: sender_user_for(unit),
-          unit: unit,
-          rule: rule
+          sender: sender_user_for(unit)
         ).deliver_now
 
         {

db/migrate/20261015040755_add_plain_text_to_communication_actions.rb

@@ -0,0 +1,5 @@
+class AddPlainTextToCommunicationActions < ActiveRecord::Migration[8.0]
+  def change
+    add_column :communication_actions, :plain_text, :boolean, default: false, null: false
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_09_16_003706) do
+ActiveRecord::Schema[8.0].define(version: 2026_10_15_040755) do
   create_table "activity_types", charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "abbreviation", null: false
@@ -101,6 +101,7 @@
     t.bigint "task_definition_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.boolean "plain_text", default: false, null: false
     t.index ["communication_rule_id"], name: "index_communication_actions_on_communication_rule_id"
     t.index ["task_definition_id"], name: "index_communication_actions_on_task_definition_id"
     t.index ["type"], name: "index_communication_actions_on_type"

test/mailers/communications_mailer_test.rb

@@ -0,0 +1,34 @@
+require 'test_helper'
+
+class CommunicationsMailerTest < ActionMailer::TestCase
+  def test_plain_text_email_contains_only_the_entered_body
+    body = "Hello Ada,\n\nPlease review your work."
+    message = communication_email(body: body, plain_text: true)
+
+    assert_match %r{\Atext/plain}, message.content_type
+    assert_nil message.html_part
+    assert_equal body, message.body.decoded.gsub("\r\n", "\n")
+  end
+
+  def test_default_email_keeps_the_notification_layout
+    message = communication_email(body: 'Please review your work.')
+
+    assert message.html_part
+    assert message.text_part
+    assert_includes message.html_part.body.decoded, 'Notification'
+  end
+
+  private
+
+  def communication_email(body:, plain_text: false)
+    CommunicationsMailer.communication_email(
+      to: 'student@example.com',
+      from: 'convenor@example.com',
+      subject: 'Reminder',
+      body: body,
+      recipient: nil,
+      sender: Struct.new(:name).new('Convenor'),
+      plain_text: plain_text
+    )
+  end
+end

test/models/communication_transfer_test.rb

@@ -28,6 +28,17 @@ def test_importing_into_a_unit_with_the_same_task_repoints_the_reference
     assert_predicate imported, :executable?
   end
 
+  def test_plain_text_email_setting_survives_export_and_import
+    @rule.communication_actions.first.update!(plain_text: true)
+    document = CommunicationTransfer.export_set(@set)
+    target_unit = unit_with_task('T1.1')
+
+    imported = CommunicationTransfer.import_set(document, target_unit)
+
+    assert_equal true, document.dig('set', 'rules', 0, 'actions', 0, 'plain_text')
+    assert_predicate imported.communication_rules.first.communication_actions.first, :plain_text?
+  end
+
   def test_importing_without_the_task_keeps_the_rule_but_blocks_the_set
     target_unit = unit_with_task('Different')