diff --git a/enterprise/app/controllers/api/v1/accounts/captain/assistants_controller.rb b/enterprise/app/controllers/api/v1/accounts/captain/assistants_controller.rb
index e5a055836..ec8e8e653 100644
--- a/enterprise/app/controllers/api/v1/accounts/captain/assistants_controller.rb
+++ b/enterprise/app/controllers/api/v1/accounts/captain/assistants_controller.rb
@@ -25,8 +25,8 @@ class Api::V1::Accounts::Captain::AssistantsController < Api::V1::Accounts::Base
 
   def playground
     response = Captain::Llm::AssistantChatService.new(assistant: @assistant).generate_response(
-      params[:message_content],
-      message_history
+      additional_message: params[:message_content],
+      message_history: message_history
     )
 
     render json: response
diff --git a/enterprise/app/jobs/captain/conversation/response_builder_job.rb b/enterprise/app/jobs/captain/conversation/response_builder_job.rb
index f341a6e98..b207bd2a4 100644
--- a/enterprise/app/jobs/captain/conversation/response_builder_job.rb
+++ b/enterprise/app/jobs/captain/conversation/response_builder_job.rb
@@ -1,6 +1,7 @@
 class Captain::Conversation::ResponseBuilderJob < ApplicationJob
   MAX_MESSAGE_LENGTH = 10_000
-  retry_on ActiveStorage::FileNotFoundError, attempts: 3
+  retry_on ActiveStorage::FileNotFoundError, attempts: 3, wait: 2.seconds
+  retry_on Faraday::BadRequestError, attempts: 3, wait: 2.seconds
 
   def perform(conversation, assistant)
     @conversation = conversation
@@ -13,7 +14,7 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
       generate_and_process_response
     end
   rescue StandardError => e
-    raise e if e.is_a?(ActiveStorage::FileNotFoundError)
+    raise e if e.is_a?(ActiveStorage::FileNotFoundError) || e.is_a?(Faraday::BadRequestError)
 
     handle_error(e)
   ensure
@@ -26,8 +27,7 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
 
   def generate_and_process_response
     @response = Captain::Llm::AssistantChatService.new(assistant: @assistant).generate_response(
-      @conversation.messages.incoming.last.content,
-      collect_previous_messages
+      message_history: collect_previous_messages
     )
 
     return process_action('handoff') if handoff_requested?
@@ -43,39 +43,19 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
       .where(message_type: [:incoming, :outgoing])
       .where(private: false)
       .map do |message|
-        {
-          content: message_content(message),
-          role: determine_role(message)
-        }
-      end
-  end
-
-  def message_content(message)
-    return message.content if message.content.present?
-    return 'User has shared a message without content' unless message.attachments.any?
-
-    audio_transcriptions = extract_audio_transcriptions(message.attachments)
-    return audio_transcriptions if audio_transcriptions.present?
-
-    'User has shared an attachment'
-  end
-
-  def extract_audio_transcriptions(attachments)
-    audio_attachments = attachments.where(file_type: :audio)
-    return '' if audio_attachments.blank?
-
-    transcriptions = ''
-    audio_attachments.each do |attachment|
-      result = Messages::AudioTranscriptionService.new(attachment).perform
-      transcriptions += result[:transcriptions] if result[:success]
+      {
+        content: prepare_multimodal_message_content(message),
+        role: determine_role(message)
+      }
     end
-    transcriptions
   end
 
   def determine_role(message)
-    return 'system' if message.content.blank?
+    message.message_type == 'incoming' ? 'user' : 'assistant'
+  end
 
-    message.message_type == 'incoming' ? 'user' : 'system'
+  def prepare_multimodal_message_content(message)
+    Captain::OpenAiMessageBuilderService.new(message: message).generate_content
   end
 
   def handoff_requested?
diff --git a/enterprise/app/services/captain/llm/assistant_chat_service.rb b/enterprise/app/services/captain/llm/assistant_chat_service.rb
index 569931d44..ca8fafaa0 100644
--- a/enterprise/app/services/captain/llm/assistant_chat_service.rb
+++ b/enterprise/app/services/captain/llm/assistant_chat_service.rb
@@ -12,9 +12,16 @@ class Captain::Llm::AssistantChatService < Llm::BaseOpenAiService
     register_tools
   end
 
-  def generate_response(input, previous_messages = [], role = 'user')
-    @messages += previous_messages
-    @messages << { role: role, content: input } if input.present?
+  # additional_message: A single message (String) from the user that should be appended to the chat.
+  #                    It can be an empty String or nil when you only want to supply historical messages.
+  # message_history:   An Array of already formatted messages that provide the previous context.
+  # role:              The role for the additional_message (defaults to `user`).
+  #
+  # NOTE: Parameters are provided as keyword arguments to improve clarity and avoid relying on
+  # positional ordering.
+  def generate_response(additional_message: nil, message_history: [], role: 'user')
+    @messages += message_history
+    @messages << { role: role, content: additional_message } if additional_message.present?
     request_chat_completion
   end
 
diff --git a/enterprise/app/services/captain/open_ai_message_builder_service.rb b/enterprise/app/services/captain/open_ai_message_builder_service.rb
new file mode 100644
index 000000000..43d2851c9
--- /dev/null
+++ b/enterprise/app/services/captain/open_ai_message_builder_service.rb
@@ -0,0 +1,60 @@
+class Captain::OpenAiMessageBuilderService
+  pattr_initialize [:message!]
+
+  def generate_content
+    parts = []
+    parts << text_part(@message.content) if @message.content.present?
+    parts.concat(attachment_parts(@message.attachments)) if @message.attachments.any?
+
+    return 'Message without content' if parts.blank?
+    return parts.first[:text] if parts.one? && parts.first[:type] == 'text'
+
+    parts
+  end
+
+  private
+
+  def text_part(text)
+    { type: 'text', text: text }
+  end
+
+  def image_part(image_url)
+    { type: 'image_url', image_url: { url: image_url } }
+  end
+
+  def attachment_parts(attachments)
+    image_attachments = attachments.where(file_type: :image)
+    image_content = image_parts(image_attachments)
+
+    transcription = extract_audio_transcriptions(attachments)
+    transcription_part = text_part(transcription) if transcription.present?
+
+    attachment_part = text_part('User has shared an attachment') if attachments.where.not(file_type: %i[image audio]).exists?
+
+    [image_content, transcription_part, attachment_part].flatten.compact
+  end
+
+  def image_parts(image_attachments)
+    image_attachments.each_with_object([]) do |attachment, parts|
+      url = get_attachment_url(attachment)
+      parts << image_part(url) if url.present?
+    end
+  end
+
+  def get_attachment_url(attachment)
+    return attachment.download_url if attachment.download_url.present?
+    return attachment.external_url if attachment.external_url.present?
+
+    attachment.file.attached? ? attachment.file_url : nil
+  end
+
+  def extract_audio_transcriptions(attachments)
+    audio_attachments = attachments.where(file_type: :audio)
+    return '' if audio_attachments.blank?
+
+    audio_attachments.map do |attachment|
+      result = Messages::AudioTranscriptionService.new(attachment).perform
+      result[:success] ? result[:transcriptions] : ''
+    end.join
+  end
+end
\ No newline at end of file
diff --git a/enterprise/app/services/enterprise/message_templates/hook_execution_service.rb b/enterprise/app/services/enterprise/message_templates/hook_execution_service.rb
index 92ccba553..ac1c3a95d 100644
--- a/enterprise/app/services/enterprise/message_templates/hook_execution_service.rb
+++ b/enterprise/app/services/enterprise/message_templates/hook_execution_service.rb
@@ -1,13 +1,34 @@
 module Enterprise::MessageTemplates::HookExecutionService
+  MAX_ATTACHMENT_WAIT_SECONDS = 4
+
   def trigger_templates
     super
     return unless should_process_captain_response?
     return perform_handoff unless inbox.captain_active?
 
-    Captain::Conversation::ResponseBuilderJob.perform_later(
-      conversation,
-      conversation.inbox.captain_assistant
-    )
+    schedule_captain_response
+  end
+
+  private
+
+  def schedule_captain_response
+    job_args = [conversation, conversation.inbox.captain_assistant]
+
+    if message.attachments.blank?
+      Captain::Conversation::ResponseBuilderJob.perform_later(*job_args)
+    else
+      wait_time = calculate_attachment_wait_time
+      Captain::Conversation::ResponseBuilderJob.set(wait: wait_time).perform_later(*job_args)
+    end
+  end
+
+  def calculate_attachment_wait_time
+    attachment_count = message.attachments.size
+    base_wait = 1.second
+
+    # Wait longer for more attachments or larger files
+    additional_wait = [attachment_count * 1, MAX_ATTACHMENT_WAIT_SECONDS].min.seconds
+    base_wait + additional_wait
   end
 
   def should_process_captain_response?
diff --git a/spec/enterprise/controllers/api/v1/accounts/captain/assistants_controller_spec.rb b/spec/enterprise/controllers/api/v1/accounts/captain/assistants_controller_spec.rb
index 1f6d83d80..80be6f30f 100644
--- a/spec/enterprise/controllers/api/v1/accounts/captain/assistants_controller_spec.rb
+++ b/spec/enterprise/controllers/api/v1/accounts/captain/assistants_controller_spec.rb
@@ -211,8 +211,8 @@ RSpec.describe 'Api::V1::Accounts::Captain::Assistants', type: :request do
 
         expect(response).to have_http_status(:success)
         expect(chat_service).to have_received(:generate_response).with(
-          valid_params[:message_content],
-          valid_params[:message_history]
+          additional_message: valid_params[:message_content],
+          message_history: valid_params[:message_history]
         )
         expect(json_response[:content]).to eq('Assistant response')
       end
@@ -232,8 +232,8 @@ RSpec.describe 'Api::V1::Accounts::Captain::Assistants', type: :request do
 
         expect(response).to have_http_status(:success)
         expect(chat_service).to have_received(:generate_response).with(
-          params_without_history[:message_content],
-          []
+          additional_message: params_without_history[:message_content],
+          message_history: []
         )
       end
     end
diff --git a/spec/enterprise/jobs/captain/conversation/response_builder_job_spec.rb b/spec/enterprise/jobs/captain/conversation/response_builder_job_spec.rb
index 1e4a6e824..c21205d52 100644
--- a/spec/enterprise/jobs/captain/conversation/response_builder_job_spec.rb
+++ b/spec/enterprise/jobs/captain/conversation/response_builder_job_spec.rb
@@ -30,5 +30,142 @@ RSpec.describe Captain::Conversation::ResponseBuilderJob, type: :job do
       account.reload
       expect(account.usage_limits[:captain][:responses][:consumed]).to eq(1)
     end
+
+    context 'when message contains an image' do
+      let(:message_with_image) { create(:message, conversation: conversation, message_type: :incoming, content: 'Can you help with this error?') }
+      let(:image_attachment) { message_with_image.attachments.create!(account: account, file_type: :image, external_url: 'https://example.com/error.jpg') }
+
+      before do
+        image_attachment
+      end
+
+      it 'includes image URL directly in the message content for OpenAI vision analysis' do
+        # Expect the generate_response to receive multimodal content with image URL
+        expect(mock_llm_chat_service).to receive(:generate_response) do |**kwargs|
+          history = kwargs[:message_history]
+          last_entry = history.last
+          expect(last_entry[:content]).to be_an(Array)
+          expect(last_entry[:content].any? { |part| part[:type] == 'text' && part[:text] == 'Can you help with this error?' }).to be true
+          expect(last_entry[:content].any? do |part|
+            part[:type] == 'image_url' && part[:image_url][:url] == 'https://example.com/error.jpg'
+          end).to be true
+          { 'response' => 'I can see the error in your image. It appears to be a database connection issue.' }
+        end
+
+        described_class.perform_now(conversation, assistant)
+      end
+    end
+  end
+
+  describe 'retry mechanisms for image processing' do
+    let(:conversation) { create(:conversation, inbox: inbox, account: account) }
+    let(:mock_llm_chat_service) { instance_double(Captain::Llm::AssistantChatService) }
+    let(:mock_message_builder) { instance_double(Captain::OpenAiMessageBuilderService) }
+
+    before do
+      create(:message, conversation: conversation, content: 'Hello with image', message_type: :incoming)
+      allow(Captain::Llm::AssistantChatService).to receive(:new).and_return(mock_llm_chat_service)
+      allow(Captain::OpenAiMessageBuilderService).to receive(:new).with(message: anything).and_return(mock_message_builder)
+      allow(mock_message_builder).to receive(:generate_content).and_return('Hello with image')
+      allow(mock_llm_chat_service).to receive(:generate_response).and_return({ 'response' => 'Test response' })
+    end
+
+    context 'when ActiveStorage::FileNotFoundError occurs' do
+      it 'handles file errors and triggers handoff' do
+        allow(mock_message_builder).to receive(:generate_content)
+          .and_raise(ActiveStorage::FileNotFoundError, 'Image file not found')
+
+        # For retryable errors, the job should handle them and proceed with handoff
+        described_class.perform_now(conversation, assistant)
+
+        # Verify handoff occurred due to repeated failures
+        expect(conversation.reload.status).to eq('open')
+      end
+
+      it 'succeeds when no error occurs' do
+        # Don't raise any error, should succeed normally
+        allow(mock_message_builder).to receive(:generate_content)
+          .and_return('Image content processed successfully')
+
+        described_class.perform_now(conversation, assistant)
+
+        expect(conversation.messages.outgoing.count).to eq(1)
+        expect(conversation.messages.outgoing.last.content).to eq('Test response')
+      end
+    end
+
+    context 'when Faraday::BadRequestError occurs' do
+      it 'handles API errors and triggers handoff' do
+        allow(mock_llm_chat_service).to receive(:generate_response)
+          .and_raise(Faraday::BadRequestError, 'Bad request to image service')
+
+        described_class.perform_now(conversation, assistant)
+        expect(conversation.reload.status).to eq('open')
+      end
+
+      it 'succeeds when no error occurs' do
+        # Don't raise any error, should succeed normally
+        allow(mock_llm_chat_service).to receive(:generate_response)
+          .and_return({ 'response' => 'Response after retry' })
+
+        described_class.perform_now(conversation, assistant)
+
+        expect(conversation.messages.outgoing.last.content).to eq('Response after retry')
+      end
+    end
+
+    context 'when image processing fails permanently' do
+      before do
+        allow(mock_message_builder).to receive(:generate_content)
+          .and_raise(ActiveStorage::FileNotFoundError, 'Image permanently unavailable')
+      end
+
+      it 'triggers handoff after max retries' do
+        # Since perform_now re-raises retryable errors, simulate the final failure after retries
+        allow(mock_message_builder).to receive(:generate_content)
+          .and_raise(StandardError, 'Max retries exceeded')
+
+        expect(ChatwootExceptionTracker).to receive(:new).and_call_original
+
+        described_class.perform_now(conversation, assistant)
+
+        expect(conversation.reload.status).to eq('open')
+      end
+    end
+
+    context 'when non-retryable error occurs' do
+      let(:standard_error) { StandardError.new('Generic error') }
+
+      before do
+        allow(mock_llm_chat_service).to receive(:generate_response).and_raise(standard_error)
+      end
+
+      it 'handles error and triggers handoff' do
+        expect(ChatwootExceptionTracker).to receive(:new)
+          .with(standard_error, account: account)
+          .and_call_original
+
+        described_class.perform_now(conversation, assistant)
+
+        expect(conversation.reload.status).to eq('open')
+      end
+
+      it 'ensures Current.executed_by is reset' do
+        expect(Current).to receive(:executed_by=).with(assistant)
+        expect(Current).to receive(:executed_by=).with(nil)
+
+        described_class.perform_now(conversation, assistant)
+      end
+    end
+  end
+
+  describe 'job configuration' do
+    it 'has retry_on configuration for retryable errors' do
+      expect(described_class).to respond_to(:retry_on)
+    end
+
+    it 'defines MAX_MESSAGE_LENGTH constant' do
+      expect(described_class::MAX_MESSAGE_LENGTH).to eq(10_000)
+    end
   end
 end
diff --git a/spec/enterprise/services/captain/open_ai_message_builder_service_spec.rb b/spec/enterprise/services/captain/open_ai_message_builder_service_spec.rb
new file mode 100644
index 000000000..76e91ae7a
--- /dev/null
+++ b/spec/enterprise/services/captain/open_ai_message_builder_service_spec.rb
@@ -0,0 +1,310 @@
+require 'rails_helper'
+
+RSpec.describe Captain::OpenAiMessageBuilderService do
+  subject(:service) { described_class.new(message: message) }
+
+  let(:message) { create(:message, content: 'Hello world') }
+
+  describe '#generate_content' do
+    context 'when message has only text content' do
+      it 'returns the text content directly' do
+        expect(service.generate_content).to eq('Hello world')
+      end
+    end
+
+    context 'when message has no content and no attachments' do
+      let(:message) { create(:message, content: nil) }
+
+      it 'returns default message' do
+        expect(service.generate_content).to eq('Message without content')
+      end
+    end
+
+    context 'when message has text content and attachments' do
+      before do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :image, external_url: 'https://example.com/image.jpg')
+        attachment.save!
+      end
+
+      it 'returns an array of content parts' do
+        result = service.generate_content
+        expect(result).to be_an(Array)
+        expect(result).to include({ type: 'text', text: 'Hello world' })
+        expect(result).to include({ type: 'image_url', image_url: { url: 'https://example.com/image.jpg' } })
+      end
+    end
+
+    context 'when message has only non-text attachments' do
+      let(:message) { create(:message, content: nil) }
+
+      before do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :image, external_url: 'https://example.com/image.jpg')
+        attachment.save!
+      end
+
+      it 'returns an array of content parts without text' do
+        result = service.generate_content
+        expect(result).to be_an(Array)
+        expect(result).to include({ type: 'image_url', image_url: { url: 'https://example.com/image.jpg' } })
+        expect(result).not_to include(hash_including(type: 'text', text: 'Hello world'))
+      end
+    end
+  end
+
+  describe '#attachment_parts' do
+    let(:message) { create(:message, content: nil) }
+    let(:attachments) { message.attachments }
+
+    context 'with image attachments' do
+      before do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :image, external_url: 'https://example.com/image.jpg')
+        attachment.save!
+      end
+
+      it 'includes image parts' do
+        result = service.send(:attachment_parts, attachments)
+        expect(result).to include({ type: 'image_url', image_url: { url: 'https://example.com/image.jpg' } })
+      end
+    end
+
+    context 'with audio attachments' do
+      let(:audio_attachment) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :audio)
+        attachment.save!
+        attachment
+      end
+
+      before do
+        allow(Messages::AudioTranscriptionService).to receive(:new).with(audio_attachment).and_return(
+          instance_double(Messages::AudioTranscriptionService, perform: { success: true, transcriptions: 'Audio transcription text' })
+        )
+      end
+
+      it 'includes transcription text part' do
+        audio_attachment # trigger creation
+        result = service.send(:attachment_parts, attachments)
+        expect(result).to include({ type: 'text', text: 'Audio transcription text' })
+      end
+    end
+
+    context 'with other file types' do
+      before do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :file)
+        attachment.save!
+      end
+
+      it 'includes generic attachment message' do
+        result = service.send(:attachment_parts, attachments)
+        expect(result).to include({ type: 'text', text: 'User has shared an attachment' })
+      end
+    end
+
+    context 'with mixed attachment types' do
+      let(:image_attachment) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :image, external_url: 'https://example.com/image.jpg')
+        attachment.save!
+        attachment
+      end
+
+      let(:audio_attachment) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :audio)
+        attachment.save!
+        attachment
+      end
+
+      let(:document_attachment) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :file)
+        attachment.save!
+        attachment
+      end
+
+      before do
+        allow(Messages::AudioTranscriptionService).to receive(:new).with(audio_attachment).and_return(
+          instance_double(Messages::AudioTranscriptionService, perform: { success: true, transcriptions: 'Audio text' })
+        )
+      end
+
+      it 'includes all relevant parts' do
+        image_attachment    # trigger creation
+        audio_attachment    # trigger creation
+        document_attachment # trigger creation
+
+        result = service.send(:attachment_parts, attachments)
+        expect(result).to include({ type: 'image_url', image_url: { url: 'https://example.com/image.jpg' } })
+        expect(result).to include({ type: 'text', text: 'Audio text' })
+        expect(result).to include({ type: 'text', text: 'User has shared an attachment' })
+      end
+    end
+  end
+
+  describe '#image_parts' do
+    let(:message) { create(:message, content: nil) }
+
+    context 'with valid image attachments' do
+      let(:image1) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :image, external_url: 'https://example.com/image1.jpg')
+        attachment.save!
+        attachment
+      end
+
+      let(:image2) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :image, external_url: 'https://example.com/image2.jpg')
+        attachment.save!
+        attachment
+      end
+
+      it 'returns image parts for all valid images' do
+        image1 # trigger creation
+        image2 # trigger creation
+
+        image_attachments = message.attachments.where(file_type: :image)
+        result = service.send(:image_parts, image_attachments)
+
+        expect(result).to include({ type: 'image_url', image_url: { url: 'https://example.com/image1.jpg' } })
+        expect(result).to include({ type: 'image_url', image_url: { url: 'https://example.com/image2.jpg' } })
+      end
+    end
+
+    context 'with image attachments without URLs' do
+      let(:image_attachment) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :image, external_url: nil)
+        attachment.save!
+        attachment
+      end
+
+      before do
+        allow(image_attachment).to receive(:file).and_return(instance_double(ActiveStorage::Attached::One, attached?: false))
+      end
+
+      it 'skips images without valid URLs' do
+        image_attachment # trigger creation
+
+        image_attachments = message.attachments.where(file_type: :image)
+        result = service.send(:image_parts, image_attachments)
+
+        expect(result).to be_empty
+      end
+    end
+  end
+
+  describe '#get_attachment_url' do
+    let(:attachment) do
+      attachment = message.attachments.build(account_id: message.account_id, file_type: :image)
+      attachment.save!
+      attachment
+    end
+
+    context 'when attachment has external_url' do
+      before { attachment.update(external_url: 'https://example.com/image.jpg') }
+
+      it 'returns external_url' do
+        expect(service.send(:get_attachment_url, attachment)).to eq('https://example.com/image.jpg')
+      end
+    end
+
+    context 'when attachment has attached file' do
+      before do
+        attachment.update(external_url: nil)
+        allow(attachment).to receive(:file).and_return(instance_double(ActiveStorage::Attached::One, attached?: true))
+        allow(attachment).to receive(:file_url).and_return('https://local.com/file.jpg')
+        allow(attachment).to receive(:download_url).and_return('')
+      end
+
+      it 'returns file_url' do
+        expect(service.send(:get_attachment_url, attachment)).to eq('https://local.com/file.jpg')
+      end
+    end
+
+    context 'when attachment has no URL or file' do
+      before do
+        attachment.update(external_url: nil)
+        allow(attachment).to receive(:file).and_return(instance_double(ActiveStorage::Attached::One, attached?: false))
+      end
+
+      it 'returns nil' do
+        expect(service.send(:get_attachment_url, attachment)).to be_nil
+      end
+    end
+  end
+
+  describe '#extract_audio_transcriptions' do
+    let(:message) { create(:message, content: nil) }
+
+    context 'with no audio attachments' do
+      it 'returns empty string' do
+        result = service.send(:extract_audio_transcriptions, message.attachments)
+        expect(result).to eq('')
+      end
+    end
+
+    context 'with successful audio transcriptions' do
+      let(:audio1) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :audio)
+        attachment.save!
+        attachment
+      end
+
+      let(:audio2) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :audio)
+        attachment.save!
+        attachment
+      end
+
+      before do
+        allow(Messages::AudioTranscriptionService).to receive(:new).with(audio1).and_return(
+          instance_double(Messages::AudioTranscriptionService, perform: { success: true, transcriptions: 'First audio text. ' })
+        )
+        allow(Messages::AudioTranscriptionService).to receive(:new).with(audio2).and_return(
+          instance_double(Messages::AudioTranscriptionService, perform: { success: true, transcriptions: 'Second audio text.' })
+        )
+      end
+
+      it 'concatenates all successful transcriptions' do
+        audio1 # trigger creation
+        audio2 # trigger creation
+
+        attachments = message.attachments
+        result = service.send(:extract_audio_transcriptions, attachments)
+        expect(result).to eq('First audio text. Second audio text.')
+      end
+    end
+
+    context 'with failed audio transcriptions' do
+      let(:audio_attachment) do
+        attachment = message.attachments.build(account_id: message.account_id, file_type: :audio)
+        attachment.save!
+        attachment
+      end
+
+      before do
+        allow(Messages::AudioTranscriptionService).to receive(:new).with(audio_attachment).and_return(
+          instance_double(Messages::AudioTranscriptionService, perform: { success: false, transcriptions: nil })
+        )
+      end
+
+      it 'returns empty string for failed transcriptions' do
+        audio_attachment # trigger creation
+
+        attachments = message.attachments
+        result = service.send(:extract_audio_transcriptions, attachments)
+        expect(result).to eq('')
+      end
+    end
+  end
+
+  describe 'private helper methods' do
+    describe '#text_part' do
+      it 'returns correct text part format' do
+        result = service.send(:text_part, 'Hello world')
+        expect(result).to eq({ type: 'text', text: 'Hello world' })
+      end
+    end
+
+    describe '#image_part' do
+      it 'returns correct image part format' do
+        result = service.send(:image_part, 'https://example.com/image.jpg')
+        expect(result).to eq({ type: 'image_url', image_url: { url: 'https://example.com/image.jpg' } })
+      end
+    end
+  end
+end