diff --git a/app/controllers/messages_controller.rb b/app/controllers/messages_controller.rb
index e505bd54d..b16573ebd 100644
--- a/app/controllers/messages_controller.rb
+++ b/app/controllers/messages_controller.rb
@@ -24,7 +24,7 @@ def index
     @streaming_message = Message.where(
       content_text: [nil, ""],
       cancelled_at: nil
-    ).find_by(id: redis.get("conversation-#{@conversation.id}-latest-assistant_message-id"))
+    ).find_by(id: @conversation.last_assistant_message_id)
   end
 
   def show
@@ -43,7 +43,7 @@ def create
 
     if @message.save
       after_create_assistant_reply = @message.conversation.latest_message_for_version(@message.version)
-      GetNextAIMessageJob.perform_later(after_create_assistant_reply.id, @assistant.id)
+      GetNextAIMessageJob.perform_later(current_user.id, after_create_assistant_reply.id, @assistant.id)
       redirect_to conversation_messages_path(@message.conversation, version: @message.version)
     else
       # what's the right flow for a failed message create? it's not this, but hacking it so tests pass until we have a plan
@@ -110,8 +110,4 @@ def message_params
     end
     modified_params
   end
-
-  def redis
-    RedisConnection.client
-  end
 end
diff --git a/app/jobs/get_next_ai_message_job.rb b/app/jobs/get_next_ai_message_job.rb
index 7a163a7b3..dfa817f44 100644
--- a/app/jobs/get_next_ai_message_job.rb
+++ b/app/jobs/get_next_ai_message_job.rb
@@ -12,12 +12,13 @@ def ai_backend
     end
   end
 
-  def perform(message_id, assistant_id, attempt = 1)
-    puts "\n### GetNextAIMessageJob.perform(#{message_id}, #{assistant_id}, #{attempt})" unless Rails.env.test?
+  def perform(user_id, message_id, assistant_id, attempt = 1)
+    puts "\n### GetNextAIMessageJob.perform(#{user_id}, #{message_id}, #{assistant_id}, #{attempt})" unless Rails.env.test?
 
-    @message      = Message.find_by(id: message_id)
+    @user         = User.find(user_id)
+    @message      = Message.find(message_id)
     @conversation = @message.conversation
-    @assistant    = Assistant.find_by(id: assistant_id)
+    @assistant    = Assistant.find(assistant_id)
     @prev_message = @conversation.messages.assistant.for_conversation_version(@message.version).find_by(index: @message.index-1)
 
     return false          if generation_was_cancelled? || message_is_populated?
@@ -153,19 +154,15 @@ def generation_was_cancelled?
 
   def message_cancelled?
     @message.cancelled? ||
-      (@cancel_counter > 1 && @message.id == redis.get("message-cancelled-id")&.to_i)
+      (@cancel_counter > 1 && @message.id == @user.reload.last_cancelled_message_id)
   end
 
   def newer_messages_in_conversation?
     @message != @conversation.latest_message_for_version(@message.version) ||
-      (@cancel_counter > 1 && @message.id != redis.get("conversation-#{@conversation.id}-latest-assistant_message-id")&.to_i)
+      (@cancel_counter > 1 && @message.id != @conversation.reload.last_assistant_message_id)
   end
 
   def message_is_populated?
     @message.content_text.present?
   end
-
-  def redis
-    RedisConnection.client
-  end
 end
diff --git a/app/models/conversation.rb b/app/models/conversation.rb
index 36fd81239..33849c2c7 100644
--- a/app/models/conversation.rb
+++ b/app/models/conversation.rb
@@ -7,6 +7,7 @@ class Conversation < ApplicationRecord
   has_many :messages, dependent: :destroy
   has_many :runs, dependent: :destroy
   has_many :steps, dependent: :destroy
+  belongs_to :last_assistant_message, class_name: "Message", optional: true
 
   after_touch :set_title_async, if: -> { title.blank? && messages.count >= 2 }
 
diff --git a/app/models/message.rb b/app/models/message.rb
index a8463c39b..1a2b3e349 100644
--- a/app/models/message.rb
+++ b/app/models/message.rb
@@ -5,6 +5,7 @@ class Message < ApplicationRecord
   belongs_to :conversation
   belongs_to :content_document, class_name: "Document", optional: true
   belongs_to :run, optional: true
+  has_one :latest_assistant_message_for, class_name: "Conversation", foreign_key: :last_assistant_message_id, dependent: :nullify
 
   enum role: %w[user assistant].index_by(&:to_sym)
 
@@ -20,7 +21,7 @@ class Message < ApplicationRecord
   validate  :validate_assistant,     if: -> { assistant.present? && Current.user }
 
   after_create :start_assistant_reply, if: :user?
-  after_create :set_latest_assistant_message, if: :assistant?
+  after_create :set_last_assistant_message, if: :assistant?
   after_save :update_assistant_on_conversation, if: -> { assistant.present? && conversation.present? }
 
   scope :ordered, -> { latest_version_for_conversation }
@@ -49,8 +50,8 @@ def start_assistant_reply
     )
   end
 
-  def set_latest_assistant_message
-    redis.set("conversation-#{conversation_id}-latest-assistant_message-id", id)
+  def set_last_assistant_message
+    conversation.update!(last_assistant_message: self)
   end
 
   def update_assistant_on_conversation
diff --git a/app/models/message/cancellable.rb b/app/models/message/cancellable.rb
index b0ae8bb30..c8d139004 100644
--- a/app/models/message/cancellable.rb
+++ b/app/models/message/cancellable.rb
@@ -2,16 +2,14 @@ module Message::Cancellable
   extend ActiveSupport::Concern
 
   included do
-    after_save :save_cancelled_id_to_redis, if: :saved_change_to_cancelled_at?
+    has_one :cancelled_by, class_name: "User", foreign_key: :last_cancelled_message_id, dependent: :nullify
+
+    after_save :set_cancelled_by, if: :saved_change_to_cancelled_at?
   end
 
   private
 
-  def save_cancelled_id_to_redis
-    redis.set("message-cancelled-id", id)
-  end
-
-  def redis
-    RedisConnection.client
+  def set_cancelled_by
+    Current.user&.update!(last_cancelled_message: self)
   end
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index f45957a1d..22b7d21f7 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -11,6 +11,7 @@ class User < ApplicationRecord
 
   has_many :assistants, dependent: :destroy
   has_many :conversations, dependent: :destroy
+  belongs_to :last_cancelled_message, class_name: "Message", optional: true
 
   serialize :preferences, coder: JsonSerializer
 
diff --git a/db/migrate/20240504212248_add_last_message_id_cancelled_to_users.rb b/db/migrate/20240504212248_add_last_message_id_cancelled_to_users.rb
new file mode 100644
index 000000000..a57ea65e2
--- /dev/null
+++ b/db/migrate/20240504212248_add_last_message_id_cancelled_to_users.rb
@@ -0,0 +1,5 @@
+class AddLastMessageIdCancelledToUsers < ActiveRecord::Migration[7.1]
+  def change
+    add_reference :users, :last_cancelled_message, null: true, foreign_key: { to_table: :messages }
+  end
+end
diff --git a/db/migrate/20240504212345_add_last_assistant_message_id_to_conversations.rb b/db/migrate/20240504212345_add_last_assistant_message_id_to_conversations.rb
new file mode 100644
index 000000000..981ce6f2f
--- /dev/null
+++ b/db/migrate/20240504212345_add_last_assistant_message_id_to_conversations.rb
@@ -0,0 +1,5 @@
+class AddLastAssistantMessageIdToConversations < ActiveRecord::Migration[7.1]
+  def change
+    add_reference :conversations, :last_assistant_message, null: true, foreign_key: { to_table: :messages }
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index e4c4ddf1f..37bdacfeb 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.1].define(version: 2024_05_01_215824) do
+ActiveRecord::Schema[7.1].define(version: 2024_05_04_212345) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -75,7 +75,9 @@
     t.string "title"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.bigint "last_assistant_message_id"
     t.index ["assistant_id"], name: "index_conversations_on_assistant_id"
+    t.index ["last_assistant_message_id"], name: "index_conversations_on_last_assistant_message_id"
     t.index ["updated_at"], name: "index_conversations_on_updated_at"
     t.index ["user_id"], name: "index_conversations_on_user_id"
   end
@@ -292,6 +294,8 @@
     t.string "openai_key"
     t.string "anthropic_key"
     t.jsonb "preferences"
+    t.bigint "last_cancelled_message_id"
+    t.index ["last_cancelled_message_id"], name: "index_users_on_last_cancelled_message_id"
   end
 
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
@@ -299,6 +303,7 @@
   add_foreign_key "assistants", "users"
   add_foreign_key "chats", "users"
   add_foreign_key "conversations", "assistants"
+  add_foreign_key "conversations", "messages", column: "last_assistant_message_id"
   add_foreign_key "conversations", "users"
   add_foreign_key "documents", "assistants"
   add_foreign_key "documents", "messages"
@@ -319,4 +324,5 @@
   add_foreign_key "steps", "assistants"
   add_foreign_key "steps", "conversations"
   add_foreign_key "steps", "runs"
+  add_foreign_key "users", "messages", column: "last_cancelled_message_id"
 end
diff --git a/test/fixtures/conversations.yml b/test/fixtures/conversations.yml
index 8e886a12c..4a7e50dbc 100644
--- a/test/fixtures/conversations.yml
+++ b/test/fixtures/conversations.yml
@@ -2,36 +2,43 @@ greeting:
   user: keith
   assistant: samantha
   title: Meeting Samantha
+  last_assistant_message: im_a_bot
 
 attachment:
   user: keith
   assistant: samantha
   title: Testing one attachment
+  last_assistant_message: not_human
 
 attachments:
   user: keith
   assistant: samantha
   title: Testing attachments
+  last_assistant_message: yes_cat_and_dog
 
 javascript:
   user: keith
   assistant: keith_gpt4
   title: Javascript popstate
+  last_assistant_message: popstate_event
 
 ruby_version:
   user: keith
   assistant: samantha
   title: Ruby version
+  last_assistant_message: latest_ruby_version
 
 hello_claude:
   user: keith
   assistant: keith_claude3
   title: Meeting Claude
+  last_assistant_message: claude_age_replying
 
 debugging:
   user: rob
   assistant: rob_gpt4
   title: Verifying Ruby syntax
+  last_assistant_message: filter_map_example
 
 #  0.1
 #  1.1
@@ -47,6 +54,7 @@ versioned:
   user: keith
   assistant: samantha
   title: Versioned conversation
+  last_assistant_message: message5_v2
 
 #  0.1
 #  1.1
@@ -60,3 +68,4 @@ versioned2:
   user: keith
   assistant: samantha
   title: Versioned v2 conversation
+  last_assistant_message: msg2_v5
diff --git a/test/fixtures/messages.yml b/test/fixtures/messages.yml
index 4560a115b..7ddf74564 100644
--- a/test/fixtures/messages.yml
+++ b/test/fixtures/messages.yml
@@ -68,6 +68,7 @@ dont_know_day:
   content_document:
   run: what_day_response
   created_at: 2023-12-30 1:05:00
+  cancelled_at: 2023-12-30 1:05:03
   index: 5
   version: 1
 
diff --git a/test/fixtures/users.yml b/test/fixtures/users.yml
index 85e489b22..e1220ec0a 100644
--- a/test/fixtures/users.yml
+++ b/test/fixtures/users.yml
@@ -5,6 +5,7 @@ keith:
   registered_at: 2023-12-19 08:40:05
   openai_key: abc123
   anthropic_key: def789
+  last_cancelled_message: dont_know_day
   preferences: {}
 
 rob:
diff --git a/test/jobs/get_next_ai_message_job_anthropic_test.rb b/test/jobs/get_next_ai_message_job_anthropic_test.rb
index a4f0a17a0..d1dd5bd64 100644
--- a/test/jobs/get_next_ai_message_job_anthropic_test.rb
+++ b/test/jobs/get_next_ai_message_job_anthropic_test.rb
@@ -3,6 +3,7 @@
 class GetNextAIMessageJobAnthropicTest < ActiveJob::TestCase
   setup do
     @conversation = conversations(:hello_claude)
+    @user = @conversation.user
     @conversation.messages.create! role: :user, content_text: "Still there?", assistant: @conversation.assistant
     @message = @conversation.latest_message_for_version(:latest)
     @test_client = TestClients::Anthropic.new(access_token: 'abc')
@@ -10,7 +11,7 @@ class GetNextAIMessageJobAnthropicTest < ActiveJob::TestCase
 
   test "populates the latest message from the assistant" do
     assert_no_difference "@conversation.messages.reload.length" do
-      assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+      assert GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
     end
 
     message_text = @test_client.messages
@@ -18,34 +19,34 @@ class GetNextAIMessageJobAnthropicTest < ActiveJob::TestCase
   end
 
   test "returns early if the message id was invalid" do
-    refute GetNextAIMessageJob.perform_now(0, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, 0, @conversation.assistant.id)
   end
 
   test "returns early if the assistant id was invalid" do
-    refute GetNextAIMessageJob.perform_now(@message.id, 0)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, 0)
   end
 
   test "returns early if the message was already generated" do
     @message.update!(content_text: "Hello")
-    refute GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
   end
 
   test "returns early if the user has replied after this" do
     @conversation.messages.create! role: :user, content_text: "Ignore that, new question:", assistant: @conversation.assistant
-    refute GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
   end
 
   test "when anthropic key is blank, a nice error message is displayed" do
     user = conversations(:greeting).user
     user.update!(anthropic_key: "")
 
-    assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    assert GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
     assert_includes @conversation.latest_message_for_version(:latest).content_text, "need to enter a valid API key for Anthropic"
   end
 
   test "when API response key is, a nice error message is displayed" do
     TestClients::Anthropic.stub :text, "" do
-      assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+      assert GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
       assert_includes @conversation.latest_message_for_version(:latest).content_text, "a blank response"
     end
   end
diff --git a/test/jobs/get_next_ai_message_job_openai_test.rb b/test/jobs/get_next_ai_message_job_openai_test.rb
index 2a8268014..7e1ac093c 100644
--- a/test/jobs/get_next_ai_message_job_openai_test.rb
+++ b/test/jobs/get_next_ai_message_job_openai_test.rb
@@ -3,6 +3,7 @@
 class GetNextAIMessageJobOpenaiTest < ActiveJob::TestCase
   setup do
     @conversation = conversations(:greeting)
+    @user = @conversation.user
     @conversation.messages.create! role: :user, content_text: "Still there?", assistant: @conversation.assistant
     @message = @conversation.latest_message_for_version(:latest)
     @test_client = TestClients::OpenAI.new(access_token: 'abc')
@@ -10,7 +11,7 @@ class GetNextAIMessageJobOpenaiTest < ActiveJob::TestCase
 
   test "populates the latest message from the assistant" do
     assert_no_difference "@conversation.messages.reload.length" do
-      assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+      assert GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
     end
 
     message_text = @test_client.chat
@@ -18,34 +19,34 @@ class GetNextAIMessageJobOpenaiTest < ActiveJob::TestCase
   end
 
   test "returns early if the message id was invalid" do
-    refute GetNextAIMessageJob.perform_now(0, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, 0, @conversation.assistant.id)
   end
 
   test "returns early if the assistant id was invalid" do
-    refute GetNextAIMessageJob.perform_now(@message.id, 0)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, 0)
   end
 
   test "returns early if the message was already generated" do
     @message.update!(content_text: "Hello")
-    refute GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
   end
 
   test "returns early if the user has replied after this" do
     @conversation.messages.create! role: :user, content_text: "Ignore that, new question:", assistant: @conversation.assistant
-    refute GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
   end
 
   test "when openai key is blank, a nice error message is displayed" do
     user = @conversation.user
     user.update!(openai_key: "")
 
-    assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    assert GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
     assert_includes @conversation.latest_message_for_version(:latest).content_text, "need to enter a valid API key for OpenAI"
   end
 
   test "when API response key is, a nice error message is displayed" do
     TestClients::OpenAI.stub :text, "" do
-      assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+      assert GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
       assert_includes @conversation.latest_message_for_version(:latest).content_text, "a blank response"
     end
   end
diff --git a/test/jobs/get_next_ai_message_job_test.rb b/test/jobs/get_next_ai_message_job_test.rb
index c16c8269e..c62db49ba 100644
--- a/test/jobs/get_next_ai_message_job_test.rb
+++ b/test/jobs/get_next_ai_message_job_test.rb
@@ -3,6 +3,7 @@
 class GetNextAIMessageJobOpenaiTest < ActiveJob::TestCase
   setup do
     @conversation = conversations(:greeting)
+    @user = @conversation.user
     @conversation.messages.create! role: :user, content_text: "Are you still there?", assistant: @conversation.assistant
     @message = @conversation.latest_message_for_version(:latest)
     @test_client = TestClients::OpenAI.new(access_token: 'abc')
@@ -11,37 +12,32 @@ class GetNextAIMessageJobOpenaiTest < ActiveJob::TestCase
   test "if a new message is created BEFORE job starts, it does not process" do
     @conversation.messages.create! role: :user, content_text: "You there?", assistant: @conversation.assistant
 
-    refute GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
     assert @message.content_text.blank?
     assert_nil @message.cancelled_at
   end
 
-  test "if a new message is created AFTER job starts, it stops streaming - this tests the redis state" do
-    m = @conversation.messages.create! role: :user, content_text: "And now?", assistant: @conversation.assistant
-    @conversation.messages.where("id >= ?", m.id).delete_all # we are reverting the database change but the redis change persists
-
-    assert_changes "@message.content_text", from: nil, to: @test_client.chat do
-      assert_changes "@message.reload.cancelled_at", from: nil do
-        assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
-      end
-    end
-  end
-
   test "if the cancel streaming button is clicked BEFORE job starts, it does not process" do
     @message.cancelled!
 
-    refute GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+    refute GetNextAIMessageJob.perform_now(@user.id, @message.id, @conversation.assistant.id)
     assert @message.content_text.blank?
     assert_not_nil @message.cancelled_at
   end
 
-  test "if the cancel streaming button is clicked AFTER job starts, it does not process - this tests the redis state" do
-    @message.cancelled! # this changes database column AND alters a redis state
-    @message.update!(cancelled_at: nil) # this undoes the column change but the redis state persists
-
-    assert_changes "@message.content_text", from: nil, to: @test_client.chat do
-      assert_changes "@message.reload.cancelled_at", from: nil do
-        assert GetNextAIMessageJob.perform_now(@message.id, @conversation.assistant.id)
+  test "if message_cancelled? starts returning true for any reason AFTER job starts, it cancels the message" do
+    # When the job first starts, it short circuits if the message is already cancelled so we are NOT going to
+    # set the message to be cancelled Instead, we are going to stub out the message_cancelled? checker so it
+    # returns true the first time it's used but false thereafter. This simulates message.cancelled! being
+    # toggled after the job has started.
+    false_on_first_run = 0
+    job = GetNextAIMessageJob.new
+    job.stub(:message_cancelled?, -> { false_on_first_run += 1; false_on_first_run != 1 }) do
+
+      assert_changes "@message.content_text", from: nil, to: @test_client.chat do
+        assert_changes "@message.reload.cancelled_at", from: nil do
+          assert job.perform(@user.id, @message.id, @conversation.assistant.id)
+        end
       end
     end
   end
diff --git a/test/models/conversation_test.rb b/test/models/conversation_test.rb
index e6b78ab51..58aecf32f 100644
--- a/test/models/conversation_test.rb
+++ b/test/models/conversation_test.rb
@@ -21,6 +21,12 @@ class ConversationTest < ActiveSupport::TestCase
     assert_instance_of Step, conversations(:greeting).steps.first
   end
 
+  test "has associated last_assistant_message but can also be nil" do
+    c = Conversation.create!(user: users(:keith), assistant: assistants(:samantha))
+    assert_nil c.last_assistant_message
+    assert_instance_of Message, conversations(:greeting).last_assistant_message
+  end
+
   test "simple create works" do
     assert_nothing_raised do
       Conversation.create!(
@@ -65,7 +71,7 @@ class ConversationTest < ActiveSupport::TestCase
         latest_message = conversation.latest_message_for_version(:latest)
         assert latest_message.assistant?
 
-        GetNextAIMessageJob.perform_now(latest_message.id, assistants(:samantha).id)
+        GetNextAIMessageJob.perform_now(users(:keith).id, latest_message.id, assistants(:samantha).id)
 
         assert_equal "Hear me", conversation.reload.title
 
diff --git a/test/models/message/cancellable_test.rb b/test/models/message/cancellable_test.rb
index 46bd03c76..b9693a309 100644
--- a/test/models/message/cancellable_test.rb
+++ b/test/models/message/cancellable_test.rb
@@ -4,28 +4,24 @@ class Message::CancellableTest < ActiveSupport::TestCase
   setup do
     @conversation = conversations(:greeting)
     @previous_id = @conversation.latest_message_for_version(:latest).id
-
-    redis.set("conversation-#{@conversation.id}-latest-assistant_message-id", @previous_id)
   end
 
-  teardown do
-    redis.set("conversation-#{@conversation.id}-latest-assistant_message-id", @previous_id) # cleanup
+  test "cancelled_by" do
+    assert_equal users(:keith), messages(:dont_know_day).cancelled_by
   end
 
   test "when a message is cancelled the redis key gets set" do
-    redis.set("message-cancelled-id", nil)
+    Current.user = users(:keith)
 
     assert_changes "messages(:im_a_bot).cancelled_at", from: nil do
-      assert_changes "redis.get('message-cancelled-id')&.to_i", to: messages(:im_a_bot).id do
+      assert_changes "users(:keith).last_cancelled_message", to: messages(:im_a_bot) do
         messages(:im_a_bot).cancelled!
       end
     end
-
-    redis.set("message-cancelled-id", nil)
   end
 
   test "creating a new message on a conversation updates the redis key for that conversation" do
-    assert_changes "redis.get('conversation-#{@conversation.id}-latest-assistant_message-id')&.to_i", from: @previous_id do
+    assert_changes "@conversation.last_assistant_message_id", from: @previous_id do
       assert_difference "@conversation.messages.count", 2 do
         @conversation.messages.create!(
           assistant: @conversation.assistant,
@@ -34,12 +30,6 @@ class Message::CancellableTest < ActiveSupport::TestCase
       end
     end
     id = @conversation.latest_message_for_version(:latest).reload.id
-    assert_equal id, redis.get("conversation-#{@conversation.id}-latest-assistant_message-id")&.to_i
-  end
-
-  private
-
-  def redis
-    RedisConnection.client
+    assert_equal id, @conversation.last_assistant_message_id
   end
 end
diff --git a/test/models/message_test.rb b/test/models/message_test.rb
index 01a18415b..ef516e42f 100644
--- a/test/models/message_test.rb
+++ b/test/models/message_test.rb
@@ -25,6 +25,11 @@ class MessageTest < ActiveSupport::TestCase
     assert_instance_of User, messages(:yes_i_do).user
   end
 
+  test "has associated latest_assistant_message_for but can be nil" do
+    assert_nil messages(:dont_know_day).latest_assistant_message_for
+    assert_instance_of Conversation, messages(:im_a_bot).latest_assistant_message_for
+  end
+
   test "create without setting Current or conversation raises" do
     assert_raises ActiveRecord::RecordInvalid do
       Message.create!(content_text: "Hello")
@@ -138,4 +143,27 @@ class MessageTest < ActiveSupport::TestCase
     conversations(:greeting).messages.create!(assistant: new_assistant, content_text: "Hello")
     assert_equal new_assistant, conversations(:greeting).reload.assistant
   end
+
+  test "messages are destroyed when a conversation is destroyed" do
+    msg1 = messages(:popstate)
+    msg2 = messages(:popstate_event)
+
+    assert_difference "Message.count", -2 do
+      msg1.conversation.destroy
+    end
+
+    assert_equal 0, Message.where(id: [msg1.id, msg2.id]).count
+  end
+
+  test "message which is referenced by conversation can be destroyed" do
+    assert_equal messages(:popstate_event), conversations(:javascript).last_assistant_message
+    messages(:popstate_event).destroy
+    assert_nil conversations(:javascript).reload.last_assistant_message
+  end
+
+  test "message which is referenced by user can be destroyed" do
+    assert_equal messages(:dont_know_day), users(:keith).last_cancelled_message
+    messages(:dont_know_day).destroy
+    assert_nil users(:keith).reload.last_cancelled_message
+  end
 end
diff --git a/test/models/user_test.rb b/test/models/user_test.rb
index 13d5fb71c..a09b74627 100644
--- a/test/models/user_test.rb
+++ b/test/models/user_test.rb
@@ -5,6 +5,11 @@ class UserTest < ActiveSupport::TestCase
     assert_instance_of Person, users(:keith).person
   end
 
+  test "has a last_cancelled_message but can be nil" do
+    assert_equal messages(:dont_know_day), users(:keith).last_cancelled_message
+    assert_nil users(:rob).last_cancelled_message
+  end
+
   test "should not validate a new user without password" do
     user = User.new
     person = Person.new(email: "example@gmail.com", personable: user)
diff --git a/test/system/conversations/messages/version_test.rb b/test/system/conversations/messages/version_test.rb
index 7d8a7227f..d61671c14 100644
--- a/test/system/conversations/messages/version_test.rb
+++ b/test/system/conversations/messages/version_test.rb
@@ -7,7 +7,7 @@ class ConversationMessagesVersionTest < ApplicationSystemTestCase
   end
 
   test "previous icon shows tooltip and next is disabled" do
-    conversations(:versioned).messages.where(version: 2).where("index > 2").delete_all
+    conversations(:versioned).messages.where(version: 2).where("index > 2").destroy_all
     visit_and_scroll_wait conversation_messages_path(conversations(:versioned), version: 2)
 
     msg = hover_last_message