diff --git a/plugins/chat/app/services/chat/add_users_to_channel.rb b/plugins/chat/app/services/chat/add_users_to_channel.rb
index 6c0325b3bce..585f44dd372 100644
--- a/plugins/chat/app/services/chat/add_users_to_channel.rb
+++ b/plugins/chat/app/services/chat/add_users_to_channel.rb
@@ -47,6 +47,10 @@ module Chat
 
     private
 
+    def fetch_channel(contract:)
+      ::Chat::Channel.includes(:chatable).find_by(id: contract.channel_id)
+    end
+
     def can_add_users_to_channel(guardian:, channel:)
       (guardian.user.admin? || channel.joined_by?(guardian.user)) &&
         channel.direct_message_channel? && channel.chatable.group
@@ -60,10 +64,6 @@ module Chat
       )
     end
 
-    def fetch_channel(contract:)
-      ::Chat::Channel.includes(:chatable).find_by(id: contract.channel_id)
-    end
-
     def upsert_memberships(channel:, target_users:)
       always_level = ::Chat::UserChatChannelMembership::NOTIFICATION_LEVELS[:always]
 
diff --git a/plugins/chat/app/services/chat/auto_remove/handle_category_updated.rb b/plugins/chat/app/services/chat/auto_remove/handle_category_updated.rb
index 6da61967c1d..909c6855704 100644
--- a/plugins/chat/app/services/chat/auto_remove/handle_category_updated.rb
+++ b/plugins/chat/app/services/chat/auto_remove/handle_category_updated.rb
@@ -14,13 +14,13 @@ module Chat
     class HandleCategoryUpdated
       include Service::Base
 
+      policy :chat_enabled
       contract do
         attribute :category_id, :integer
 
         validates :category_id, presence: true
       end
       step :assign_defaults
-      policy :chat_enabled
       model :category
       model :category_channel_ids
       model :users
diff --git a/plugins/chat/app/services/chat/auto_remove/handle_destroyed_group.rb b/plugins/chat/app/services/chat/auto_remove/handle_destroyed_group.rb
index 36bada03d11..18e7d6a6dd0 100644
--- a/plugins/chat/app/services/chat/auto_remove/handle_destroyed_group.rb
+++ b/plugins/chat/app/services/chat/auto_remove/handle_destroyed_group.rb
@@ -21,13 +21,13 @@ module Chat
     class HandleDestroyedGroup
       include Service::Base
 
+      policy :chat_enabled
       contract do
-        attribute :destroyed_group_user_ids
+        attribute :destroyed_group_user_ids, :array
 
         validates :destroyed_group_user_ids, presence: true
       end
       step :assign_defaults
-      policy :chat_enabled
       policy :not_everyone_allowed
       model :scoped_users
       step :remove_users_outside_allowed_groups
@@ -48,7 +48,7 @@ module Chat
         !SiteSetting.chat_allowed_groups_map.include?(Group::AUTO_GROUPS[:everyone])
       end
 
-      def fetch_scoped_users(destroyed_group_user_ids:)
+      def fetch_scoped_users(contract:)
         User
           .real
           .activated
@@ -56,7 +56,7 @@ module Chat
           .not_staged
           .includes(:group_users)
           .where("NOT admin AND NOT moderator")
-          .where(id: destroyed_group_user_ids)
+          .where(id: contract.destroyed_group_user_ids)
           .joins(:user_chat_channel_memberships)
           .distinct
       end
diff --git a/plugins/chat/app/services/chat/auto_remove/handle_user_removed_from_group.rb b/plugins/chat/app/services/chat/auto_remove/handle_user_removed_from_group.rb
index 9154ff133c8..5d497d5d850 100644
--- a/plugins/chat/app/services/chat/auto_remove/handle_user_removed_from_group.rb
+++ b/plugins/chat/app/services/chat/auto_remove/handle_user_removed_from_group.rb
@@ -20,13 +20,13 @@ module Chat
     class HandleUserRemovedFromGroup
       include Service::Base
 
+      policy :chat_enabled
       contract do
         attribute :user_id, :integer
 
         validates :user_id, presence: true
       end
       step :assign_defaults
-      policy :chat_enabled
       policy :not_everyone_allowed
       model :user
       policy :user_not_staff
diff --git a/plugins/chat/app/services/chat/flag_message.rb b/plugins/chat/app/services/chat/flag_message.rb
index ad610dddebe..dabb638f1ee 100644
--- a/plugins/chat/app/services/chat/flag_message.rb
+++ b/plugins/chat/app/services/chat/flag_message.rb
@@ -37,7 +37,7 @@ module Chat
 
       validates :message_id, presence: true
       validates :channel_id, presence: true
-      validates :flag_type_id, inclusion: { in: ->(_flag_type) { ::ReviewableScore.types.values } }
+      validates :flag_type_id, inclusion: { in: -> { ::ReviewableScore.types.values } }
     end
     model :message
     policy :can_flag_message_in_channel
diff --git a/plugins/chat/app/services/chat/list_channel_messages.rb b/plugins/chat/app/services/chat/list_channel_messages.rb
index 6632b4e1c3b..6f77b71e306 100644
--- a/plugins/chat/app/services/chat/list_channel_messages.rb
+++ b/plugins/chat/app/services/chat/list_channel_messages.rb
@@ -39,7 +39,6 @@ module Chat
                 },
                 allow_nil: true
     end
-
     model :channel
     policy :can_view_channel
     model :membership, optional: true
diff --git a/plugins/chat/app/services/chat/search_chatable.rb b/plugins/chat/app/services/chat/search_chatable.rb
index 829f9dc9841..dbe2e41e1c0 100644
--- a/plugins/chat/app/services/chat/search_chatable.rb
+++ b/plugins/chat/app/services/chat/search_chatable.rb
@@ -34,7 +34,7 @@ module Chat
     private
 
     def clean_term(contract:)
-      context[:term] = contract.term&.downcase&.strip&.gsub(/^[@#]+/, "")
+      contract.term = contract.term&.downcase&.strip&.gsub(/^[@#]+/, "")
     end
 
     def fetch_memberships(guardian:)
@@ -44,31 +44,31 @@ module Chat
     def fetch_users(guardian:, contract:)
       return unless contract.include_users
       return unless guardian.can_create_direct_message?
-      search_users(context, guardian)
+      search_users(contract, guardian)
     end
 
     def fetch_groups(guardian:, contract:)
       return unless contract.include_groups
       return unless guardian.can_create_direct_message?
-      search_groups(context, guardian)
+      search_groups(contract, guardian)
     end
 
     def fetch_category_channels(guardian:, contract:)
       return unless contract.include_category_channels
       return unless SiteSetting.enable_public_channels
-      search_category_channels(context, guardian)
+      search_category_channels(contract, guardian)
     end
 
     def fetch_direct_message_channels(guardian:, contract:, users:)
       return unless contract.include_direct_message_channels
       return unless guardian.can_create_direct_message?
-      search_direct_message_channels(context, guardian, contract, users)
+      search_direct_message_channels(guardian, contract, users)
     end
 
-    def search_users(context, guardian)
-      user_search = ::UserSearch.new(context.term, limit: SEARCH_RESULT_LIMIT)
+    def search_users(contract, guardian)
+      user_search = ::UserSearch.new(contract.term, limit: SEARCH_RESULT_LIMIT)
 
-      if context.term.blank?
+      if contract.term.blank?
         user_search = user_search.scoped_users
       else
         user_search = user_search.search
@@ -80,45 +80,45 @@ module Chat
       user_search = user_search.real(allowed_bot_user_ids: allowed_bot_user_ids)
       user_search = user_search.includes(:user_option)
 
-      if context.excluded_memberships_channel_id
+      if contract.excluded_memberships_channel_id
         user_search =
           user_search.where(
             "NOT EXISTS (SELECT 1 FROM user_chat_channel_memberships WHERE user_id = users.id AND chat_channel_id = ?)",
-            context.excluded_memberships_channel_id,
+            contract.excluded_memberships_channel_id,
           )
       end
 
       user_search
     end
 
-    def search_groups(context, guardian)
+    def search_groups(contract, guardian)
       Group
         .visible_groups(guardian.user)
         .includes(users: :user_option)
         .where(
           "groups.name ILIKE :term_like OR groups.full_name ILIKE :term_like",
-          term_like: "%#{context.term}%",
+          term_like: "%#{contract.term}%",
         )
         .limit(SEARCH_RESULT_LIMIT)
     end
 
-    def search_category_channels(context, guardian)
+    def search_category_channels(contract, guardian)
       ::Chat::ChannelFetcher.secured_public_channel_search(
         guardian,
         status: :open,
-        filter: context.term,
+        filter: contract.term,
         filter_on_category_name: false,
         match_filter_on_starts_with: false,
         limit: SEARCH_RESULT_LIMIT,
       )
     end
 
-    def search_direct_message_channels(context, guardian, contract, users)
+    def search_direct_message_channels(guardian, contract, users)
       channels =
         ::Chat::ChannelFetcher.secured_direct_message_channels_search(
           guardian.user.id,
           guardian,
-          filter: context.term,
+          filter: contract.term,
           match_filter_on_starts_with: false,
           limit: SEARCH_RESULT_LIMIT,
         ) || []
diff --git a/plugins/chat/app/services/chat/update_channel.rb b/plugins/chat/app/services/chat/update_channel.rb
index 9bb1248d1e2..1898a5eba6d 100644
--- a/plugins/chat/app/services/chat/update_channel.rb
+++ b/plugins/chat/app/services/chat/update_channel.rb
@@ -65,13 +65,11 @@ module Chat
     end
 
     def update_channel(channel:, contract:)
-      channel.assign_attributes(contract.attributes)
-      context[:threading_enabled_changed] = channel.threading_enabled_changed?
-      channel.save!
+      channel.update!(contract.attributes)
     end
 
     def mark_all_threads_as_read_if_needed(channel:)
-      return if !(context.threading_enabled_changed && channel.threading_enabled)
+      return unless channel.threading_enabled_previously_changed?(to: true)
       Jobs.enqueue(Jobs::Chat::MarkAllChannelThreadsRead, channel_id: channel.id)
     end
 
diff --git a/plugins/chat/app/services/chat/update_channel_status.rb b/plugins/chat/app/services/chat/update_channel_status.rb
index 1816599846c..cf3b2892ce5 100644
--- a/plugins/chat/app/services/chat/update_channel_status.rb
+++ b/plugins/chat/app/services/chat/update_channel_status.rb
@@ -17,7 +17,7 @@ module Chat
 
     model :channel, :fetch_channel
     contract do
-      attribute :status
+      attribute :status, :string
 
       validates :status, inclusion: { in: Chat::Channel.editable_statuses.keys }
     end
@@ -30,13 +30,13 @@ module Chat
       Chat::Channel.find_by(id: channel_id)
     end
 
-    def check_channel_permission(guardian:, channel:, status:)
+    def check_channel_permission(guardian:, channel:, contract:)
       guardian.can_preview_chat_channel?(channel) &&
-        guardian.can_change_channel_status?(channel, status.to_sym)
+        guardian.can_change_channel_status?(channel, contract.status.to_sym)
     end
 
-    def change_status(channel:, status:, guardian:)
-      channel.public_send("#{status}!", guardian.user)
+    def change_status(channel:, contract:, guardian:)
+      channel.public_send("#{contract.status}!", guardian.user)
     end
   end
 end
diff --git a/plugins/chat/spec/requests/chat/api/channel_messages_controller_spec.rb b/plugins/chat/spec/requests/chat/api/channel_messages_controller_spec.rb
index 63c12100989..25e6b3846d1 100644
--- a/plugins/chat/spec/requests/chat/api/channel_messages_controller_spec.rb
+++ b/plugins/chat/spec/requests/chat/api/channel_messages_controller_spec.rb
@@ -76,19 +76,19 @@ RSpec.describe Chat::Api::ChannelMessagesController do
 
   describe "#create" do
     context "when force_thread param is given" do
-      it "removes it from params" do
-        sign_in(current_user)
+      let!(:message) { Fabricate(:chat_message, chat_channel: channel) }
 
-        message_1 = Fabricate(:chat_message, chat_channel: channel)
+      before { sign_in(current_user) }
 
+      it "ignores it" do
         expect {
           post "/chat/#{channel.id}.json",
                params: {
-                 in_reply_to_id: message_1.id,
+                 in_reply_to_id: message.id,
                  message: "test",
                  force_thread: true,
                }
-        }.to change { Chat::Thread.where(force: false).count }.by(1)
+        }.not_to change { Chat::Thread.where(force: true).count }
       end
     end
   end
diff --git a/plugins/chat/spec/services/auto_remove/handle_category_updated_spec.rb b/plugins/chat/spec/services/auto_remove/handle_category_updated_spec.rb
index 87ef5c75d92..76700891df5 100644
--- a/plugins/chat/spec/services/auto_remove/handle_category_updated_spec.rb
+++ b/plugins/chat/spec/services/auto_remove/handle_category_updated_spec.rb
@@ -51,9 +51,7 @@ RSpec.describe Chat::AutoRemove::HandleCategoryUpdated do
           updated_category.category_groups.delete_all
         end
 
-        it "sets the service result as successful" do
-          expect(result).to be_a_success
-        end
+        it { is_expected.to run_successfully }
 
         it "does not kick any users since the default permission is Everyone (full)" do
           expect { result }.not_to change {
@@ -90,9 +88,7 @@ RSpec.describe Chat::AutoRemove::HandleCategoryUpdated do
           group_2.add(user_1)
         end
 
-        it "sets the service result as successful" do
-          expect(result).to be_a_success
-        end
+        it { is_expected.to run_successfully }
 
         it "kicks all regular users who are not in any groups with reply + see permissions" do
           expect { result }.to change {
diff --git a/plugins/chat/spec/services/auto_remove/handle_destroyed_group_spec.rb b/plugins/chat/spec/services/auto_remove/handle_destroyed_group_spec.rb
index 3a1d436d9e5..7b84ac10654 100644
--- a/plugins/chat/spec/services/auto_remove/handle_destroyed_group_spec.rb
+++ b/plugins/chat/spec/services/auto_remove/handle_destroyed_group_spec.rb
@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::AutoRemove::HandleDestroyedGroup do
+  describe described_class::Contract, type: :model do
+    it { is_expected.to validate_presence_of(:destroyed_group_user_ids) }
+  end
+
   describe ".call" do
     subject(:result) { described_class.call(params) }
 
@@ -45,9 +49,7 @@ RSpec.describe Chat::AutoRemove::HandleDestroyedGroup do
             channel_1.add(admin_2)
           end
 
-          it "sets the service result as successful" do
-            expect(result).to be_a_success
-          end
+          it { is_expected.to run_successfully }
 
           it "removes the destroyed_group_user_ids from all public channels" do
             expect { result }.to change {
@@ -132,9 +134,7 @@ RSpec.describe Chat::AutoRemove::HandleDestroyedGroup do
             channel_1.add(admin_2)
           end
 
-          it "sets the service result as successful" do
-            expect(result).to be_a_success
-          end
+          it { is_expected.to run_successfully }
 
           it "does not remove any memberships" do
             expect { result }.not_to change { Chat::UserChatChannelMembership.count }
@@ -196,9 +196,7 @@ RSpec.describe Chat::AutoRemove::HandleDestroyedGroup do
             )
           end
 
-          it "sets the service result as successful" do
-            expect(result).to be_a_success
-          end
+          it { is_expected.to run_successfully }
 
           it "removes the destroyed_group_user_ids from the channel" do
             expect { result }.to change {
@@ -237,9 +235,7 @@ RSpec.describe Chat::AutoRemove::HandleDestroyedGroup do
           context "when one of the users is not in any of the groups" do
             before { user_2.change_trust_level!(TrustLevel[3]) }
 
-            it "sets the service result as successful" do
-              expect(result).to be_a_success
-            end
+            it { is_expected.to run_successfully }
 
             it "removes the destroyed_group_user_ids from the channel" do
               expect { result }.to change {
diff --git a/plugins/chat/spec/services/chat/create_direct_message_channel_spec.rb b/plugins/chat/spec/services/chat/create_direct_message_channel_spec.rb
index fa234b6bf4d..7c57b9ea3fa 100644
--- a/plugins/chat/spec/services/chat/create_direct_message_channel_spec.rb
+++ b/plugins/chat/spec/services/chat/create_direct_message_channel_spec.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::CreateDirectMessageChannel do
-  describe Chat::CreateDirectMessageChannel::Contract, type: :model do
+  describe described_class::Contract, type: :model do
     subject(:contract) { described_class.new(params) }
 
     let(:params) { { target_usernames: %w[lechuck elaine] } }
@@ -45,10 +45,6 @@ RSpec.describe Chat::CreateDirectMessageChannel do
     context "when all steps pass" do
       it { is_expected.to run_successfully }
 
-      it "sets the service result as successful" do
-        expect(result).to be_a_success
-      end
-
       it "updates user count" do
         expect(result.channel.user_count).to eq(3) # current user + user_1 + user_2
       end
diff --git a/plugins/chat/spec/services/chat/create_thread_spec.rb b/plugins/chat/spec/services/chat/create_thread_spec.rb
index e2479837901..e76e1f69411 100644
--- a/plugins/chat/spec/services/chat/create_thread_spec.rb
+++ b/plugins/chat/spec/services/chat/create_thread_spec.rb
@@ -1,9 +1,10 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::CreateThread do
-  describe Chat::CreateThread::Contract, type: :model do
+  describe described_class::Contract, type: :model do
     it { is_expected.to validate_presence_of :channel_id }
     it { is_expected.to validate_presence_of :original_message_id }
+    it { is_expected.to validate_length_of(:title).is_at_most(Chat::Thread::MAX_TITLE_LENGTH) }
   end
 
   describe ".call" do
@@ -68,12 +69,6 @@ RSpec.describe Chat::CreateThread do
       it { is_expected.to fail_a_contract }
     end
 
-    context "when title is too long" do
-      let(:title) { "a" * Chat::Thread::MAX_TITLE_LENGTH + "a" }
-
-      it { is_expected.to fail_a_contract }
-    end
-
     context "when original message is not found" do
       fab!(:channel_2) { Fabricate(:chat_channel, threading_enabled: true) }
 
diff --git a/plugins/chat/spec/services/chat/flag_message_spec.rb b/plugins/chat/spec/services/chat/flag_message_spec.rb
index 83b58bebaf1..f382984a2c6 100644
--- a/plugins/chat/spec/services/chat/flag_message_spec.rb
+++ b/plugins/chat/spec/services/chat/flag_message_spec.rb
@@ -2,8 +2,6 @@
 
 RSpec.describe Chat::FlagMessage do
   describe described_class::Contract, type: :model do
-    subject(:contract) { described_class.new }
-
     it { is_expected.to validate_presence_of(:channel_id) }
     it { is_expected.to validate_presence_of(:message_id) }
 
@@ -26,9 +24,6 @@ RSpec.describe Chat::FlagMessage do
     let(:message) { nil }
     let(:is_warning) { nil }
     let(:take_action) { nil }
-
-    before { SiteSetting.direct_message_enabled_groups = Group::AUTO_GROUPS[:everyone] }
-
     let(:params) do
       {
         guardian: guardian,
@@ -41,23 +36,34 @@ RSpec.describe Chat::FlagMessage do
       }
     end
 
+    before { SiteSetting.direct_message_enabled_groups = Group::AUTO_GROUPS[:everyone] }
+
     context "when all steps pass" do
       fab!(:current_user) { Fabricate(:admin) }
 
+      let(:reviewable) { Reviewable.last }
+
       it { is_expected.to run_successfully }
 
       it "flags the message" do
         expect { result }.to change { Reviewable.count }.by(1)
-
-        reviewable = Reviewable.last
-        expect(reviewable.target_type).to eq("ChatMessage")
-        expect(reviewable.created_by_id).to eq(current_user.id)
-        expect(reviewable.target_created_by_id).to eq(message_1.user.id)
-        expect(reviewable.target_id).to eq(message_1.id)
-        expect(reviewable.payload).to eq("message_cooked" => message_1.cooked)
+        expect(reviewable).to have_attributes(
+          target: message_1,
+          created_by: current_user,
+          target_created_by: message_1.user,
+          payload: {
+            "message_cooked" => message_1.cooked,
+          },
+        )
       end
     end
 
+    context "when contract is invalid" do
+      let(:channel_id) { nil }
+
+      it { is_expected.to fail_a_contract }
+    end
+
     context "when channel is not found" do
       before { params[:channel_id] = -999 }
 
diff --git a/plugins/chat/spec/services/chat/invite_users_to_channel_spec.rb b/plugins/chat/spec/services/chat/invite_users_to_channel_spec.rb
index 6e9a8c7e03b..02682d14836 100644
--- a/plugins/chat/spec/services/chat/invite_users_to_channel_spec.rb
+++ b/plugins/chat/spec/services/chat/invite_users_to_channel_spec.rb
@@ -1,88 +1,93 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::InviteUsersToChannel do
-  subject(:result) { described_class.call(params) }
-
   describe described_class::Contract, type: :model do
-    subject(:contract) { described_class.new }
-
     it { is_expected.to validate_presence_of :channel_id }
     it { is_expected.to validate_presence_of :user_ids }
   end
 
-  fab!(:current_user) { Fabricate(:admin) }
-  fab!(:user_1) { Fabricate(:user) }
-  fab!(:user_2) { Fabricate(:user) }
-  fab!(:channel_1) { Fabricate(:chat_channel) }
-  fab!(:group_1) { Fabricate(:group) }
+  describe ".call" do
+    subject(:result) { described_class.call(**params, **dependencies) }
 
-  let(:guardian) { current_user.guardian }
-  let(:user_ids) { [user_1.id, user_2.id] }
-  let(:message_id) { nil }
-  let(:params) do
-    { guardian: guardian, channel_id: channel_1.id, message_id: message_id, user_ids: user_ids }
-  end
+    fab!(:current_user) { Fabricate(:admin) }
+    fab!(:user_1) { Fabricate(:user) }
+    fab!(:user_2) { Fabricate(:user) }
+    fab!(:channel_1) { Fabricate(:chat_channel) }
+    fab!(:group_1) { Fabricate(:group) }
 
-  before do
-    group_1.add(user_1)
-    SiteSetting.chat_allowed_groups = group_1.id
-  end
+    let(:guardian) { current_user.guardian }
+    let(:user_ids) { [user_1.id, user_2.id] }
+    let(:message_id) { nil }
+    let(:params) { { channel_id: channel_1.id, message_id:, user_ids: } }
+    let(:dependencies) { { guardian: } }
 
-  context "when all steps pass" do
-    it { is_expected.to run_successfully }
-
-    it "creates the notifications for allowed users" do
-      result
-
-      notification = user_1.reload.notifications.last
-      expect(notification.notification_type).to eq(::Notification.types[:chat_invitation])
-
-      notification = user_2.reload.notifications.last
-      expect(notification).to be_nil
+    before do
+      group_1.add(user_1)
+      SiteSetting.chat_allowed_groups = group_1.id
     end
 
-    it "doesnt create notifications for suspended users" do
-      user_1.update!(suspended_till: 2.days.from_now, suspended_at: Time.now)
+    context "when all steps pass" do
+      it { is_expected.to run_successfully }
 
-      result
-
-      notification = user_1.reload.notifications.last
-      expect(notification).to be_nil
-    end
-
-    it "doesnt create notifications for users with disabled chat" do
-      user_1.user_option.update!(chat_enabled: false)
-
-      result
-
-      notification = user_1.reload.notifications.last
-      expect(notification).to be_nil
-    end
-
-    context "when message id is provided" do
-      fab!(:message_1) { Fabricate(:chat_message, chat_channel: channel_1) }
-
-      let(:message_id) { message_1.id }
-
-      it "sets the message id on the notification" do
+      it "creates the notifications for allowed users" do
         result
 
-        data = JSON.parse(user_1.reload.notifications.last.data)
-        expect(data["chat_message_id"]).to eq(message_id)
+        notification = user_1.reload.notifications.last
+        expect(notification.notification_type).to eq(::Notification.types[:chat_invitation])
+
+        notification = user_2.reload.notifications.last
+        expect(notification).to be_nil
+      end
+
+      it "doesnt create notifications for suspended users" do
+        user_1.update!(suspended_till: 2.days.from_now, suspended_at: Time.now)
+
+        result
+
+        notification = user_1.reload.notifications.last
+        expect(notification).to be_nil
+      end
+
+      it "doesnt create notifications for users with disabled chat" do
+        user_1.user_option.update!(chat_enabled: false)
+
+        result
+
+        notification = user_1.reload.notifications.last
+        expect(notification).to be_nil
+      end
+
+      context "when message id is provided" do
+        fab!(:message_1) { Fabricate(:chat_message, chat_channel: channel_1) }
+
+        let(:message_id) { message_1.id }
+
+        it "sets the message id on the notification" do
+          result
+
+          data = JSON.parse(user_1.reload.notifications.last.data)
+          expect(data["chat_message_id"]).to eq(message_id)
+        end
       end
     end
-  end
 
-  context "when channel model is not found" do
-    before { params[:channel_id] = -1 }
+    context "when contract is invalid" do
+      let(:user_ids) { nil }
 
-    it { is_expected.to fail_to_find_a_model(:channel) }
-  end
+      it { is_expected.to fail_a_contract }
+    end
 
-  context "when current user can't view channel" do
-    fab!(:current_user) { Fabricate(:user) }
-    fab!(:channel_1) { Fabricate(:private_category_channel) }
+    context "when channel model is not found" do
+      before { params[:channel_id] = -1 }
 
-    it { is_expected.to fail_a_policy(:can_view_channel) }
+      it { is_expected.to fail_to_find_a_model(:channel) }
+    end
+
+    context "when current user can't view channel" do
+      fab!(:current_user) { Fabricate(:user) }
+      fab!(:channel_1) { Fabricate(:private_category_channel) }
+
+      it { is_expected.to fail_a_policy(:can_view_channel) }
+    end
   end
 end
diff --git a/plugins/chat/spec/services/chat/search_chatable_spec.rb b/plugins/chat/spec/services/chat/search_chatable_spec.rb
index 943f4723103..174d395c217 100644
--- a/plugins/chat/spec/services/chat/search_chatable_spec.rb
+++ b/plugins/chat/spec/services/chat/search_chatable_spec.rb
@@ -47,10 +47,10 @@ RSpec.describe Chat::SearchChatable do
 
       it "cleans the term" do
         params[:term] = "#bob"
-        expect(result.term).to eq("bob")
+        expect(result.contract.term).to eq("bob")
 
         params[:term] = "@bob"
-        expect(result.term).to eq("bob")
+        expect(result.contract.term).to eq("bob")
       end
 
       it "fetches user memberships" do
diff --git a/plugins/chat/spec/services/chat/stop_message_streaming_spec.rb b/plugins/chat/spec/services/chat/stop_message_streaming_spec.rb
index e4b6058907b..8e7b21a33fc 100644
--- a/plugins/chat/spec/services/chat/stop_message_streaming_spec.rb
+++ b/plugins/chat/spec/services/chat/stop_message_streaming_spec.rb
@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::StopMessageStreaming do
+  describe described_class::Contract, type: :model do
+    it { is_expected.to validate_presence_of(:message_id) }
+  end
+
   describe ".call" do
     subject(:result) { described_class.call(params) }
 
diff --git a/plugins/chat/spec/services/chat/trash_message_spec.rb b/plugins/chat/spec/services/chat/trash_message_spec.rb
index b7bc327a458..d9dff95ec00 100644
--- a/plugins/chat/spec/services/chat/trash_message_spec.rb
+++ b/plugins/chat/spec/services/chat/trash_message_spec.rb
@@ -1,24 +1,29 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::TrashMessage do
-  fab!(:current_user) { Fabricate(:user) }
-  let!(:guardian) { Guardian.new(current_user) }
-  fab!(:message) { Fabricate(:chat_message, user: current_user) }
+  describe described_class::Contract, type: :model do
+    it { is_expected.to validate_presence_of(:message_id) }
+    it { is_expected.to validate_presence_of(:channel_id) }
+  end
 
   describe ".call" do
-    subject(:result) { described_class.call(params) }
+    subject(:result) { described_class.call(**params, **dependencies) }
+
+    fab!(:current_user) { Fabricate(:user) }
+    fab!(:message) { Fabricate(:chat_message, user: current_user) }
+
+    let(:guardian) { Guardian.new(current_user) }
+    let(:params) { { message_id: message.id, channel_id: } }
+    let(:dependencies) { { guardian: } }
+    let(:channel_id) { message.chat_channel_id }
 
     context "when params are not valid" do
-      let(:params) { { guardian: guardian } }
+      let(:params) { {} }
 
       it { is_expected.to fail_a_contract }
     end
 
     context "when params are valid" do
-      let(:params) do
-        { guardian: guardian, message_id: message.id, channel_id: message.chat_channel_id }
-      end
-
       context "when the user does not have permission to delete" do
         before { message.update!(user: Fabricate(:admin)) }
 
@@ -26,9 +31,7 @@ RSpec.describe Chat::TrashMessage do
       end
 
       context "when the channel does not match the message" do
-        let(:params) do
-          { guardian: guardian, message_id: message.id, channel_id: Fabricate(:chat_channel).id }
-        end
+        let(:channel_id) { -1 }
 
         it { is_expected.to fail_to_find_a_model(:message) }
       end
diff --git a/plugins/chat/spec/services/chat/trash_messages_spec.rb b/plugins/chat/spec/services/chat/trash_messages_spec.rb
index 10ac0e19c9d..c0dae7e7aac 100644
--- a/plugins/chat/spec/services/chat/trash_messages_spec.rb
+++ b/plugins/chat/spec/services/chat/trash_messages_spec.rb
@@ -1,26 +1,30 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::TrashMessages do
-  fab!(:current_user) { Fabricate(:user) }
-  let!(:guardian) { Guardian.new(current_user) }
-  fab!(:chat_channel) { Fabricate(:chat_channel) }
-  fab!(:message1) { Fabricate(:chat_message, user: current_user, chat_channel: chat_channel) }
-  fab!(:message2) { Fabricate(:chat_message, user: current_user, chat_channel: chat_channel) }
+  describe described_class::Contract, type: :model do
+    it { is_expected.to validate_presence_of(:channel_id) }
+    it { is_expected.to allow_values([1], (1..200).to_a).for(:message_ids) }
+    it { is_expected.not_to allow_values([], (1..201).to_a).for(:message_ids) }
+  end
 
   describe ".call" do
-    subject(:result) { described_class.call(params) }
+    subject(:result) { described_class.call(**params, **dependencies) }
+
+    fab!(:current_user) { Fabricate(:user) }
+    fab!(:chat_channel) { Fabricate(:chat_channel) }
+    fab!(:message1) { Fabricate(:chat_message, user: current_user, chat_channel: chat_channel) }
+    fab!(:message2) { Fabricate(:chat_message, user: current_user, chat_channel: chat_channel) }
+    let(:guardian) { Guardian.new(current_user) }
+    let(:params) { { message_ids: [message1.id, message2.id], channel_id: chat_channel.id } }
+    let(:dependencies) { { guardian: } }
 
     context "when params are not valid" do
-      let(:params) { { guardian: guardian } }
+      let(:params) { {} }
 
       it { is_expected.to fail_a_contract }
     end
 
     context "when params are valid" do
-      let(:params) do
-        { guardian: guardian, message_ids: [message1.id, message2.id], channel_id: chat_channel.id }
-      end
-
       context "when the user does not have permission to delete" do
         before { message1.update!(user: Fabricate(:admin)) }
 
@@ -29,11 +33,7 @@ RSpec.describe Chat::TrashMessages do
 
       context "when the channel does not match the message" do
         let(:params) do
-          {
-            guardian: guardian,
-            message_ids: [message1.id, message2.id],
-            channel_id: Fabricate(:chat_channel).id,
-          }
+          { message_ids: [message1.id, message2.id], channel_id: Fabricate(:chat_channel).id }
         end
 
         it { is_expected.to fail_to_find_a_model(:messages) }
diff --git a/plugins/chat/spec/services/chat/update_channel_status_spec.rb b/plugins/chat/spec/services/chat/update_channel_status_spec.rb
index b3ccccec7d6..9df907e8d2f 100644
--- a/plugins/chat/spec/services/chat/update_channel_status_spec.rb
+++ b/plugins/chat/spec/services/chat/update_channel_status_spec.rb
@@ -1,52 +1,57 @@
 # frozen_string_literal: true
 
 RSpec.describe(Chat::UpdateChannelStatus) do
-  subject(:result) do
-    described_class.call(guardian: guardian, channel_id: channel.id, status: status)
+  describe described_class::Contract, type: :model do
+    it do
+      is_expected.to validate_inclusion_of(:status).in_array(Chat::Channel.editable_statuses.keys)
+    end
   end
 
-  fab!(:channel) { Fabricate(:chat_channel) }
-  fab!(:current_user) { Fabricate(:admin) }
+  describe ".call" do
+    subject(:result) { described_class.call(**params, **dependencies) }
 
-  let(:guardian) { Guardian.new(current_user) }
-  let(:status) { "open" }
+    fab!(:channel) { Fabricate(:chat_channel) }
+    fab!(:current_user) { Fabricate(:admin) }
 
-  context "when no channel_id is given" do
-    subject(:result) { described_class.call(guardian: guardian, status: status) }
+    let(:params) { { channel_id:, status: } }
+    let(:dependencies) { { guardian: } }
+    let(:guardian) { Guardian.new(current_user) }
+    let(:status) { "open" }
+    let(:channel_id) { channel.id }
 
-    it { is_expected.to fail_to_find_a_model(:channel) }
-  end
+    context "when no channel_id is given" do
+      let(:channel_id) { nil }
 
-  context "when user is not allowed to change channel status" do
-    fab!(:current_user) { Fabricate(:user) }
+      it { is_expected.to fail_to_find_a_model(:channel) }
+    end
 
-    it { is_expected.to fail_a_policy(:check_channel_permission) }
-  end
+    context "when user is not allowed to change channel status" do
+      let!(:current_user) { Fabricate(:user) }
 
-  context "when status is not allowed" do
-    (Chat::Channel.statuses.keys - Chat::Channel.editable_statuses.keys).each do |na_status|
-      context "when status is '#{na_status}'" do
-        let(:status) { na_status }
+      it { is_expected.to fail_a_policy(:check_channel_permission) }
+    end
 
-        it { is_expected.to fail_a_contract }
+    context "when contract is invalid" do
+      let(:status) { :invalid_status }
+
+      it { is_expected.to fail_a_contract }
+    end
+
+    context "when new status is the same than the existing one" do
+      let(:status) { channel.status }
+
+      it { is_expected.to fail_a_policy(:check_channel_permission) }
+    end
+
+    context "when everything's ok" do
+      let(:status) { "closed" }
+
+      it { is_expected.to run_successfully }
+
+      it "changes the status" do
+        result
+        expect(channel.reload).to be_closed
       end
     end
   end
-
-  context "when new status is the same than the existing one" do
-    let(:status) { channel.status }
-
-    it { is_expected.to fail_a_policy(:check_channel_permission) }
-  end
-
-  context "when status is allowed" do
-    let(:status) { "closed" }
-
-    it { is_expected.to run_successfully }
-
-    it "changes the status" do
-      result
-      expect(channel.reload).to be_closed
-    end
-  end
 end
diff --git a/plugins/chat/spec/services/chat/update_thread_notification_settings_spec.rb b/plugins/chat/spec/services/chat/update_thread_notification_settings_spec.rb
index c026504b399..ff72bfbfa94 100644
--- a/plugins/chat/spec/services/chat/update_thread_notification_settings_spec.rb
+++ b/plugins/chat/spec/services/chat/update_thread_notification_settings_spec.rb
@@ -1,10 +1,13 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::UpdateThreadNotificationSettings do
-  describe Chat::UpdateThreadNotificationSettings::Contract, type: :model do
+  describe described_class::Contract, type: :model do
+    let(:notification_levels) { Chat::UserChatThreadMembership.notification_levels.values }
+
     it { is_expected.to validate_presence_of :channel_id }
     it { is_expected.to validate_presence_of :thread_id }
     it { is_expected.to validate_presence_of :notification_level }
+    it { is_expected.to validate_inclusion_of(:notification_level).in_array(notification_levels) }
   end
 
   describe ".call" do
diff --git a/plugins/chat/spec/services/chat/update_thread_spec.rb b/plugins/chat/spec/services/chat/update_thread_spec.rb
index 5be66c740f2..00f8f48fbbd 100644
--- a/plugins/chat/spec/services/chat/update_thread_spec.rb
+++ b/plugins/chat/spec/services/chat/update_thread_spec.rb
@@ -1,8 +1,9 @@
 # frozen_string_literal: true
 
 RSpec.describe Chat::UpdateThread do
-  describe Chat::UpdateThread::Contract, type: :model do
+  describe described_class::Contract, type: :model do
     it { is_expected.to validate_presence_of :thread_id }
+    it { is_expected.to validate_length_of(:title).is_at_most(Chat::Thread::MAX_TITLE_LENGTH) }
   end
 
   describe ".call" do
@@ -42,12 +43,6 @@ RSpec.describe Chat::UpdateThread do
       it { is_expected.to fail_a_contract }
     end
 
-    context "when title is too long" do
-      let(:title) { "a" * Chat::Thread::MAX_TITLE_LENGTH + "a" }
-
-      it { is_expected.to fail_a_contract }
-    end
-
     context "when thread is not found" do
       before { thread.destroy! }
 
diff --git a/plugins/chat/spec/services/chat/upsert_draft_spec.rb b/plugins/chat/spec/services/chat/upsert_draft_spec.rb
index 5727730c255..4dcc5004bd3 100644
--- a/plugins/chat/spec/services/chat/upsert_draft_spec.rb
+++ b/plugins/chat/spec/services/chat/upsert_draft_spec.rb
@@ -2,8 +2,6 @@
 
 RSpec.describe Chat::UpsertDraft do
   describe described_class::Contract, type: :model do
-    subject(:contract) { described_class.new(data: nil, channel_id: nil, thread_id: nil) }
-
     it { is_expected.to validate_presence_of :channel_id }
   end