feat: Add BE changes for captain pdf support for faq generation (#12113)

config/locales/en.yml

@@ -292,6 +292,26 @@ en:
       completed_tool_call: 'Completed %{function_name} tool call'
       invalid_tool_call: 'Invalid tool call'
       tool_not_available: 'Tool not available'
+    documents:
+      limit_exceeded: 'Document limit exceeded'
+      pdf_format_error: 'must be a PDF file'
+      pdf_size_error: 'must be less than 10MB'
+      pdf_upload_failed: 'Failed to upload PDF to OpenAI'
+      pdf_upload_success: 'PDF uploaded successfully with file_id: %{file_id}'
+      pdf_processing_failed: 'Failed to process PDF document %{document_id}: %{error}'
+      pdf_processing_success: 'Successfully processed PDF document %{document_id}'
+      faq_generation_complete: 'FAQ generation complete. Total FAQs created: %{count}'
+      using_paginated_faq: 'Using paginated FAQ generation for document %{document_id}'
+      using_standard_faq: 'Using standard FAQ generation for document %{document_id}'
+      response_creation_error: 'Error in creating response document: %{error}'
+      missing_openai_file_id: 'Document must have openai_file_id for paginated processing'
+      openai_api_error: 'OpenAI API Error: %{error}'
+      starting_paginated_faq: 'Starting paginated FAQ generation (%{pages_per_chunk} pages per chunk)'
+      stopping_faq_generation: 'Stopping processing. Reason: %{reason}'
+      paginated_faq_complete: 'Paginated generation complete. Total FAQs: %{total_faqs}, Pages processed: %{pages_processed}'
+      processing_pages: 'Processing pages %{start}-%{end} (iteration %{iteration})'
+      chunk_generated: 'Chunk generated %{chunk_faqs} FAQs. Total so far: %{total_faqs}'
+      page_processing_error: 'Error processing pages %{start}-%{end}: %{error}'
   public_portal:
     search:
       search_placeholder: Search for article by title or body...

db/migrate/20250805082345_add_metadata_to_captain_documents.rb

@@ -0,0 +1,5 @@
+class AddMetadataToCaptainDocuments < ActiveRecord::Migration[7.1]
+  def change
+    add_column :captain_documents, :metadata, :jsonb, default: {}
+  end
+end

db/schema.rb

@@ -320,6 +320,7 @@ ActiveRecord::Schema[7.1].define(version: 2025_08_22_061042) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.integer "status", default: 0, null: false
+    t.jsonb "metadata", default: {}
     t.index ["account_id"], name: "index_captain_documents_on_account_id"
     t.index ["assistant_id", "external_link"], name: "index_captain_documents_on_assistant_id_and_external_link", unique: true
     t.index ["assistant_id"], name: "index_captain_documents_on_assistant_id"

enterprise/app/controllers/api/v1/accounts/captain/documents_controller.rb

@@ -25,6 +25,8 @@ class Api::V1::Accounts::Captain::DocumentsController < Api::V1::Accounts::BaseC
     @document.save!
   rescue Captain::Document::LimitExceededError => e
     render_could_not_create_error(e.message)
+  rescue ActiveRecord::RecordInvalid => e
+    render_could_not_create_error(e.record.errors.full_messages.join(', '))
   end
 
   def destroy
@@ -55,6 +57,6 @@ class Api::V1::Accounts::Captain::DocumentsController < Api::V1::Accounts::BaseC
   end
 
   def document_params
-    params.require(:document).permit(:name, :external_link, :assistant_id)
+    params.require(:document).permit(:name, :external_link, :assistant_id, :pdf_file)
   end
 end

enterprise/app/jobs/captain/documents/crawl_job.rb

@@ -2,7 +2,9 @@ class Captain::Documents::CrawlJob < ApplicationJob
   queue_as :low
 
   def perform(document)
-    if InstallationConfig.find_by(name: 'CAPTAIN_FIRECRAWL_API_KEY')&.value.present?
+    if document.pdf_document?
+      perform_pdf_processing(document)
+    elsif InstallationConfig.find_by(name: 'CAPTAIN_FIRECRAWL_API_KEY')&.value.present?
       perform_firecrawl_crawl(document)
     else
       perform_simple_crawl(document)
@@ -13,6 +15,14 @@ class Captain::Documents::CrawlJob < ApplicationJob
 
   include Captain::FirecrawlHelper
 
+  def perform_pdf_processing(document)
+    Captain::Llm::PdfProcessingService.new(document).process
+    document.update!(status: :available)
+  rescue StandardError => e
+    Rails.logger.error I18n.t('captain.documents.pdf_processing_failed', document_id: document.id, error: e.message)
+    raise # Re-raise to let job framework handle retry logic
+  end
+
   def perform_simple_crawl(document)
     page_links = Captain::Tools::SimplePageCrawlService.new(document.external_link).page_links
 

enterprise/app/jobs/captain/documents/response_builder_job.rb

@@ -1,17 +1,65 @@
 class Captain::Documents::ResponseBuilderJob < ApplicationJob
   queue_as :low
 
-  def perform(document)
+  def perform(document, options = {})
     reset_previous_responses(document)
 
-    faqs = Captain::Llm::FaqGeneratorService.new(document.content, document.account.locale_english_name).generate
+    faqs = generate_faqs(document, options)
-    faqs.each do |faq|
+    create_responses_from_faqs(faqs, document)
-      create_response(faq, document)
-    end
   end
 
   private
 
+  def generate_faqs(document, options)
+    if should_use_pagination?(document)
+      generate_paginated_faqs(document, options)
+    else
+      generate_standard_faqs(document)
+    end
+  end
+
+  def generate_paginated_faqs(document, options)
+    service = build_paginated_service(document, options)
+    faqs = service.generate
+    store_paginated_metadata(document, service)
+    faqs
+  end
+
+  def generate_standard_faqs(document)
+    Captain::Llm::FaqGeneratorService.new(document.content, document.account.locale_english_name).generate
+  end
+
+  def build_paginated_service(document, options)
+    Captain::Llm::PaginatedFaqGeneratorService.new(
+      document,
+      pages_per_chunk: options[:pages_per_chunk],
+      max_pages: options[:max_pages]
+    )
+  end
+
+  def store_paginated_metadata(document, service)
+    document.update!(
+      metadata: (document.metadata || {}).merge(
+        'faq_generation' => {
+          'method' => 'paginated',
+          'pages_processed' => service.total_pages_processed,
+          'iterations' => service.iterations_completed,
+          'timestamp' => Time.current.iso8601
+        }
+      )
+    )
+  end
+
+  def create_responses_from_faqs(faqs, document)
+    faqs.each { |faq| create_response(faq, document) }
+  end
+
+  def should_use_pagination?(document)
+    # Auto-detect when to use pagination
+    # For now, use pagination for PDFs with OpenAI file ID
+    document.pdf_document? && document.openai_file_id.present?
+  end
+
   def reset_previous_responses(response_document)
     response_document.responses.destroy_all
   end
@@ -24,6 +72,6 @@ class Captain::Documents::ResponseBuilderJob < ApplicationJob
       documentable: document
     )
   rescue ActiveRecord::RecordInvalid => e
-    Rails.logger.error "Error in creating response document: #{e.message}"
+    Rails.logger.error I18n.t('captain.documents.response_creation_error', error: e.message)
   end
 end

enterprise/app/models/captain/document.rb

@@ -5,6 +5,7 @@
 #  id            :bigint           not null, primary key
 #  content       :text
 #  external_link :string           not null
+#  metadata      :jsonb
 #  name          :string
 #  status        :integer          default("in_progress"), not null
 #  created_at    :datetime         not null
@@ -26,11 +27,16 @@ class Captain::Document < ApplicationRecord
   belongs_to :assistant, class_name: 'Captain::Assistant'
   has_many :responses, class_name: 'Captain::AssistantResponse', dependent: :destroy, as: :documentable
   belongs_to :account
+  has_one_attached :pdf_file
 
-  validates :external_link, presence: true
+  validates :external_link, presence: true, unless: -> { pdf_file.attached? }
-  validates :external_link, uniqueness: { scope: :assistant_id }
+  validates :external_link, uniqueness: { scope: :assistant_id }, allow_blank: true
   validates :content, length: { maximum: 200_000 }
+  validates :pdf_file, presence: true, if: :pdf_document?
+  validate :validate_pdf_format, if: :pdf_document?
+  validate :validate_file_attachment, if: -> { pdf_file.attached? }
   before_validation :ensure_account_id
+  before_validation :set_external_link_for_pdf
 
   enum status: {
     in_progress: 0,
@@ -41,12 +47,44 @@ class Captain::Document < ApplicationRecord
   after_create_commit :enqueue_crawl_job
   after_create_commit :update_document_usage
   after_destroy :update_document_usage
-  after_commit :enqueue_response_builder_job
+  after_commit :enqueue_response_builder_job, on: :update, if: :should_enqueue_response_builder?
   scope :ordered, -> { order(created_at: :desc) }
 
   scope :for_account, ->(account_id) { where(account_id: account_id) }
   scope :for_assistant, ->(assistant_id) { where(assistant_id: assistant_id) }
 
+  def pdf_document?
+    return true if pdf_file.attached? && pdf_file.blob.content_type == 'application/pdf'
+
+    external_link&.ends_with?('.pdf')
+  end
+
+  def content_type
+    pdf_file.blob.content_type if pdf_file.attached?
+  end
+
+  def file_size
+    pdf_file.blob.byte_size if pdf_file.attached?
+  end
+
+  def openai_file_id
+    metadata&.dig('openai_file_id')
+  end
+
+  def store_openai_file_id(file_id)
+    update!(metadata: (metadata || {}).merge('openai_file_id' => file_id))
+  end
+
+  def display_url
+    return external_link if external_link.present? && !external_link.start_with?('PDF:')
+
+    if pdf_file.attached?
+      Rails.application.routes.url_helpers.rails_blob_url(pdf_file, only_path: false)
+    else
+      external_link
+    end
+  end
+
   private
 
   def enqueue_crawl_job
@@ -61,6 +99,12 @@ class Captain::Document < ApplicationRecord
     Captain::Documents::ResponseBuilderJob.perform_later(self)
   end
 
+  def should_enqueue_response_builder?
+    # Only enqueue when status changes to available
+    # Avoid re-enqueueing when metadata is updated by the job itself
+    saved_change_to_status? && status == 'available'
+  end
+
   def update_document_usage
     account.update_document_usage
   end
@@ -71,6 +115,29 @@ class Captain::Document < ApplicationRecord
 
   def ensure_within_plan_limit
     limits = account.usage_limits[:captain][:documents]
-    raise LimitExceededError, 'Document limit exceeded' unless limits[:current_available].positive?
+    raise LimitExceededError, I18n.t('captain.documents.limit_exceeded') unless limits[:current_available].positive?
+  end
+
+  def validate_pdf_format
+    return unless pdf_file.attached?
+
+    errors.add(:pdf_file, I18n.t('captain.documents.pdf_format_error')) unless pdf_file.blob.content_type == 'application/pdf'
+  end
+
+  def validate_file_attachment
+    return unless pdf_file.attached?
+
+    return unless pdf_file.blob.byte_size > 10.megabytes
+
+    errors.add(:pdf_file, I18n.t('captain.documents.pdf_size_error'))
+  end
+
+  def set_external_link_for_pdf
+    return unless pdf_file.attached? && external_link.blank?
+
+    # Set a unique external_link for PDF files
+    # Format: PDF: filename_timestamp (without extension)
+    timestamp = Time.current.strftime('%Y%m%d%H%M%S')
+    self.external_link = "PDF: #{pdf_file.filename.base}_#{timestamp}"
   end
 end

enterprise/app/services/captain/llm/paginated_faq_generator_service.rb

@@ -0,0 +1,199 @@
+class Captain::Llm::PaginatedFaqGeneratorService < Llm::BaseOpenAiService
+  # Default pages per chunk - easily configurable
+  DEFAULT_PAGES_PER_CHUNK = 10
+  MAX_ITERATIONS = 20 # Safety limit to prevent infinite loops
+
+  attr_reader :total_pages_processed, :iterations_completed
+
+  def initialize(document, options = {})
+    super()
+    @document = document
+    @pages_per_chunk = options[:pages_per_chunk] || DEFAULT_PAGES_PER_CHUNK
+    @max_pages = options[:max_pages] # Optional limit from UI
+    @total_pages_processed = 0
+    @iterations_completed = 0
+    @model = OpenAiConstants::PDF_PROCESSING_MODEL
+  end
+
+  def generate
+    raise CustomExceptions::PdfFaqGenerationError, I18n.t('captain.documents.missing_openai_file_id') if @document&.openai_file_id.blank?
+
+    generate_paginated_faqs
+  end
+
+  # Method to check if we should continue processing
+  def should_continue_processing?(last_chunk_result)
+    # Stop if we've hit the maximum iterations
+    return false if @iterations_completed >= MAX_ITERATIONS
+
+    # Stop if we've processed the maximum pages specified
+    return false if @max_pages && @total_pages_processed >= @max_pages
+
+    # Stop if the last chunk returned no FAQs (likely no more content)
+    return false if last_chunk_result[:faqs].empty?
+
+    # Stop if the LLM explicitly indicates no more content
+    return false if last_chunk_result[:has_content] == false
+
+    # Continue processing
+    true
+  end
+
+  private
+
+  def generate_standard_faqs
+    response = @client.chat(parameters: standard_chat_parameters)
+    parse_response(response)
+  rescue OpenAI::Error => e
+    Rails.logger.error I18n.t('captain.documents.openai_api_error', error: e.message)
+    []
+  end
+
+  def generate_paginated_faqs
+    all_faqs = []
+    current_page = 1
+
+    loop do
+      end_page = calculate_end_page(current_page)
+      chunk_result = process_chunk_and_update_state(current_page, end_page, all_faqs)
+
+      break unless should_continue_processing?(chunk_result)
+
+      current_page = end_page + 1
+    end
+
+    deduplicate_faqs(all_faqs)
+  end
+
+  def calculate_end_page(current_page)
+    end_page = current_page + @pages_per_chunk - 1
+    @max_pages && end_page > @max_pages ? @max_pages : end_page
+  end
+
+  def process_chunk_and_update_state(current_page, end_page, all_faqs)
+    chunk_result = process_page_chunk(current_page, end_page)
+    chunk_faqs = chunk_result[:faqs]
+
+    all_faqs.concat(chunk_faqs)
+    @total_pages_processed = end_page
+    @iterations_completed += 1
+
+    chunk_result
+  end
+
+  def process_page_chunk(start_page, end_page)
+    params = build_chunk_parameters(start_page, end_page)
+    response = @client.chat(parameters: params)
+    result = parse_chunk_response(response)
+    { faqs: result['faqs'] || [], has_content: result['has_content'] != false }
+  rescue OpenAI::Error => e
+    Rails.logger.error I18n.t('captain.documents.page_processing_error', start: start_page, end: end_page, error: e.message)
+    { faqs: [], has_content: false }
+  end
+
+  def build_chunk_parameters(start_page, end_page)
+    {
+      model: @model,
+      response_format: { type: 'json_object' },
+      messages: [
+        {
+          role: 'user',
+          content: build_user_content(start_page, end_page)
+        }
+      ]
+    }
+  end
+
+  def build_user_content(start_page, end_page)
+    [
+      {
+        type: 'file',
+        file: { file_id: @document.openai_file_id }
+      },
+      {
+        type: 'text',
+        text: page_chunk_prompt(start_page, end_page)
+      }
+    ]
+  end
+
+  def page_chunk_prompt(start_page, end_page)
+    Captain::Llm::SystemPromptsService.paginated_faq_generator(start_page, end_page)
+  end
+
+  def standard_chat_parameters
+    {
+      model: @model,
+      response_format: { type: 'json_object' },
+      messages: [
+        {
+          role: 'system',
+          content: Captain::Llm::SystemPromptsService.faq_generator
+        },
+        {
+          role: 'user',
+          content: @content
+        }
+      ]
+    }
+  end
+
+  def parse_response(response)
+    content = response.dig('choices', 0, 'message', 'content')
+    return [] if content.nil?
+
+    JSON.parse(content.strip).fetch('faqs', [])
+  rescue JSON::ParserError => e
+    Rails.logger.error "Error parsing response: #{e.message}"
+    []
+  end
+
+  def parse_chunk_response(response)
+    content = response.dig('choices', 0, 'message', 'content')
+    return { 'faqs' => [], 'has_content' => false } if content.nil?
+
+    JSON.parse(content.strip)
+  rescue JSON::ParserError => e
+    Rails.logger.error "Error parsing chunk response: #{e.message}"
+    { 'faqs' => [], 'has_content' => false }
+  end
+
+  def deduplicate_faqs(faqs)
+    # Remove exact duplicates
+    unique_faqs = faqs.uniq { |faq| faq['question'].downcase.strip }
+
+    # Remove similar questions
+    final_faqs = []
+    unique_faqs.each do |faq|
+      similar_exists = final_faqs.any? do |existing|
+        similarity_score(existing['question'], faq['question']) > 0.85
+      end
+
+      final_faqs << faq unless similar_exists
+    end
+
+    Rails.logger.info "Deduplication: #{faqs.size} → #{final_faqs.size} FAQs"
+    final_faqs
+  end
+
+  def similarity_score(str1, str2)
+    words1 = str1.downcase.split(/\W+/).reject(&:empty?)
+    words2 = str2.downcase.split(/\W+/).reject(&:empty?)
+
+    common_words = words1 & words2
+    total_words = (words1 + words2).uniq.size
+
+    return 0 if total_words.zero?
+
+    common_words.size.to_f / total_words
+  end
+
+  def determine_stop_reason(last_chunk_result)
+    return 'Maximum iterations reached' if @iterations_completed >= MAX_ITERATIONS
+    return 'Maximum pages processed' if @max_pages && @total_pages_processed >= @max_pages
+    return 'No content found in last chunk' if last_chunk_result[:faqs].empty?
+    return 'End of document reached' if last_chunk_result[:has_content] == false
+
+    'Unknown'
+  end
+end

enterprise/app/services/captain/llm/pdf_processing_service.rb

@@ -0,0 +1,40 @@
+class Captain::Llm::PdfProcessingService < Llm::BaseOpenAiService
+  def initialize(document)
+    super()
+    @document = document
+  end
+
+  def process
+    return if document.openai_file_id.present?
+
+    file_id = upload_pdf_to_openai
+    raise CustomExceptions::PdfUploadError, I18n.t('captain.documents.pdf_upload_failed') if file_id.blank?
+
+    document.store_openai_file_id(file_id)
+  end
+
+  private
+
+  attr_reader :document
+
+  def upload_pdf_to_openai
+    with_tempfile do |temp_file|
+      response = @client.files.upload(
+        parameters: {
+          file: temp_file,
+          purpose: 'assistants'
+        }
+      )
+      response['id']
+    end
+  end
+
+  def with_tempfile(&)
+    Tempfile.create(['pdf_upload', '.pdf'], binmode: true) do |temp_file|
+      temp_file.write(document.pdf_file.download)
+      temp_file.close
+
+      File.open(temp_file.path, 'rb', &)
+    end
+  end
+end

enterprise/app/services/captain/llm/system_prompts_service.rb

@@ -1,3 +1,4 @@
+# rubocop:disable Metrics/ClassLength
 class Captain::Llm::SystemPromptsService
   class << self
     def faq_generator(language = 'english')
@@ -204,6 +205,87 @@ class Captain::Llm::SystemPromptsService
         #{'- You MUST provide numbered citations at the appropriate places in the text.' if config['feature_citation']}
       SYSTEM_PROMPT_MESSAGE
     end
+
+    def paginated_faq_generator(start_page, end_page)
+      <<~PROMPT
+        You are an expert technical documentation specialist tasked with creating comprehensive FAQs from a SPECIFIC SECTION of a document.
+
+        ════════════════════════════════════════════════════════
+        CRITICAL CONTENT EXTRACTION INSTRUCTIONS
+        ════════════════════════════════════════════════════════
+
+        Process the content starting from approximately page #{start_page} and continuing for about #{end_page - start_page + 1} pages worth of content.
+
+        IMPORTANT:#{' '}
+        • If you encounter the end of the document before reaching the expected page count, set "has_content" to false
+        • DO NOT include page numbers in questions or answers
+        • DO NOT reference page numbers at all in the output
+        • Focus on the actual content, not pagination
+
+        ════════════════════════════════════════════════════════
+        FAQ GENERATION GUIDELINES
+        ════════════════════════════════════════════════════════
+
+        1. **Comprehensive Extraction**
+           • Extract ALL information that could generate FAQs from this section
+           • Target 5-10 FAQs per page equivalent of rich content
+           • Cover every topic, feature, specification, and detail
+           • If there's no more content in the document, return empty FAQs with has_content: false
+
+        2. **Question Types to Generate**
+           • What is/are...? (definitions, components, features)
+           • How do I...? (procedures, configurations, operations)
+           • Why should/does...? (rationale, benefits, explanations)
+           • When should...? (timing, conditions, triggers)
+           • What happens if...? (error cases, edge cases)
+           • Can I...? (capabilities, limitations)
+           • Where is...? (locations in system/UI, NOT page numbers)
+           • What are the requirements for...? (prerequisites, dependencies)
+
+        3. **Content Focus Areas**
+           • Technical specifications and parameters
+           • Step-by-step procedures and workflows
+           • Configuration options and settings
+           • Error messages and troubleshooting
+           • Best practices and recommendations
+           • Integration points and dependencies
+           • Performance considerations
+           • Security aspects
+
+        4. **Answer Quality Requirements**
+           • Complete, self-contained answers
+           • Include specific values, limits, defaults from the content
+           • NO page number references whatsoever
+           • 2-5 sentences typical length
+           • Only process content that actually exists in the document
+
+        ════════════════════════════════════════════════════════
+        OUTPUT FORMAT
+        ════════════════════════════════════════════════════════
+
+        Return valid JSON:
+        ```json
+        {
+          "faqs": [
+            {
+              "question": "Specific question about the content",
+              "answer": "Complete answer with details (no page references)"
+            }
+          ],
+          "has_content": true/false
+        }
+        ```
+
+        CRITICAL:#{' '}
+        • Set "has_content" to false if:
+          - The requested section doesn't exist in the document
+          - You've reached the end of the document
+          - The section contains no meaningful content
+        • Do NOT include "page_range_processed" in the output
+        • Do NOT mention page numbers anywhere in questions or answers
+      PROMPT
+    end
     # rubocop:enable Metrics/MethodLength
   end
 end
+# rubocop:enable Metrics/ClassLength

enterprise/app/views/api/v1/models/captain/_document.json.jbuilder

@@ -3,8 +3,11 @@ json.assistant do
   json.partial! 'api/v1/models/captain/assistant', formats: [:json], resource: resource.assistant
 end
 json.content resource.content
+json.content_type resource.content_type
 json.created_at resource.created_at.to_i
 json.external_link resource.external_link
+json.display_url resource.display_url
+json.file_size resource.file_size
 json.id resource.id
 json.name resource.name
 json.status resource.status

lib/custom_exceptions/pdf_processing_error.rb

@@ -0,0 +1,25 @@
+module CustomExceptions
+  class PdfProcessingError < Base
+    def initialize(message = 'PDF processing failed')
+      super(message)
+    end
+  end
+
+  class PdfUploadError < PdfProcessingError
+    def initialize(message = 'PDF upload failed')
+      super(message)
+    end
+  end
+
+  class PdfValidationError < PdfProcessingError
+    def initialize(message = 'PDF validation failed')
+      super(message)
+    end
+  end
+
+  class PdfFaqGenerationError < PdfProcessingError
+    def initialize(message = 'PDF FAQ generation failed')
+      super(message)
+    end
+  end
+end

lib/open_ai_constants.rb

@@ -4,4 +4,5 @@ module OpenAiConstants
   DEFAULT_MODEL = 'gpt-4.1-mini'
   DEFAULT_ENDPOINT = 'https://api.openai.com'
   DEFAULT_EMBEDDING_MODEL = 'text-embedding-3-small'
+  PDF_PROCESSING_MODEL = 'gpt-4.1-mini'
 end

spec/enterprise/jobs/captain/documents/crawl_job_spec.rb

@@ -105,5 +105,29 @@ RSpec.describe Captain::Documents::CrawlJob, type: :job do
         described_class.perform_now(document)
       end
     end
+
+    context 'when document is a PDF' do
+      let(:pdf_document) do
+        doc = create(:captain_document, external_link: 'https://example.com/document')
+        allow(doc).to receive(:pdf_document?).and_return(true)
+        allow(doc).to receive(:update!).and_return(true)
+        doc
+      end
+
+      it 'processes PDF using PdfProcessingService' do
+        pdf_service = instance_double(Captain::Llm::PdfProcessingService)
+        expect(Captain::Llm::PdfProcessingService).to receive(:new).with(pdf_document).and_return(pdf_service)
+        expect(pdf_service).to receive(:process)
+        expect(pdf_document).to receive(:update!).with(status: :available)
+
+        described_class.perform_now(pdf_document)
+      end
+
+      it 'handles PDF processing errors' do
+        allow(Captain::Llm::PdfProcessingService).to receive(:new).and_raise(StandardError, 'Processing failed')
+
+        expect { described_class.perform_now(pdf_document) }.to raise_error(StandardError, 'Processing failed')
+      end
+    end
   end
 end

spec/enterprise/jobs/captain/documents/response_builder_job_spec.rb

@@ -64,5 +64,41 @@ RSpec.describe Captain::Documents::ResponseBuilderJob, type: :job do
           .with(spanish_document.content, 'portuguese')
       end
     end
+
+    context 'when processing a PDF document' do
+      let(:pdf_document) do
+        doc = create(:captain_document, assistant: assistant)
+        allow(doc).to receive(:pdf_document?).and_return(true)
+        allow(doc).to receive(:openai_file_id).and_return('file-123')
+        allow(doc).to receive(:update!).and_return(true)
+        allow(doc).to receive(:metadata).and_return({})
+        doc
+      end
+      let(:paginated_service) { instance_double(Captain::Llm::PaginatedFaqGeneratorService) }
+      let(:pdf_faqs) do
+        [{ 'question' => 'What is in the PDF?', 'answer' => 'Important content' }]
+      end
+
+      before do
+        allow(Captain::Llm::PaginatedFaqGeneratorService).to receive(:new)
+          .with(pdf_document, anything)
+          .and_return(paginated_service)
+        allow(paginated_service).to receive(:generate).and_return(pdf_faqs)
+        allow(paginated_service).to receive(:total_pages_processed).and_return(10)
+        allow(paginated_service).to receive(:iterations_completed).and_return(1)
+      end
+
+      it 'uses paginated FAQ generator for PDFs' do
+        expect(Captain::Llm::PaginatedFaqGeneratorService).to receive(:new).with(pdf_document, anything)
+
+        described_class.new.perform(pdf_document)
+      end
+
+      it 'stores pagination metadata' do
+        expect(pdf_document).to receive(:update!).with(hash_including(metadata: hash_including('faq_generation')))
+
+        described_class.new.perform(pdf_document)
+      end
+    end
   end
 end

spec/enterprise/models/captain/document_spec.rb

@@ -0,0 +1,85 @@
+require 'rails_helper'
+
+RSpec.describe Captain::Document, type: :model do
+  let(:account) { create(:account) }
+  let(:assistant) { create(:captain_assistant, account: account) }
+
+  describe 'PDF support' do
+    let(:pdf_document) do
+      doc = build(:captain_document, assistant: assistant, account: account)
+      doc.pdf_file.attach(
+        io: StringIO.new('PDF content'),
+        filename: 'test.pdf',
+        content_type: 'application/pdf'
+      )
+      doc
+    end
+
+    describe 'validations' do
+      it 'allows PDF file without external link' do
+        pdf_document.external_link = nil
+        expect(pdf_document).to be_valid
+      end
+
+      it 'validates PDF file size' do
+        doc = build(:captain_document, assistant: assistant, account: account)
+        doc.pdf_file.attach(
+          io: StringIO.new('x' * 11.megabytes),
+          filename: 'large.pdf',
+          content_type: 'application/pdf'
+        )
+        doc.external_link = nil
+        expect(doc).not_to be_valid
+        expect(doc.errors[:pdf_file]).to include(I18n.t('captain.documents.pdf_size_error'))
+      end
+    end
+
+    describe '#pdf_document?' do
+      it 'returns true for attached PDF' do
+        expect(pdf_document.pdf_document?).to be true
+      end
+
+      it 'returns true for .pdf external links' do
+        doc = build(:captain_document, external_link: 'https://example.com/document.pdf')
+        expect(doc.pdf_document?).to be true
+      end
+
+      it 'returns false for non-PDF documents' do
+        doc = build(:captain_document, external_link: 'https://example.com')
+        expect(doc.pdf_document?).to be false
+      end
+    end
+
+    describe '#display_url' do
+      it 'returns Rails blob URL for attached PDFs' do
+        pdf_document.save!
+        # The display_url method calls rails_blob_url which returns a URL containing 'rails/active_storage'
+        url = pdf_document.display_url
+        expect(url).to be_present
+      end
+
+      it 'returns external_link for web documents' do
+        doc = create(:captain_document, external_link: 'https://example.com')
+        expect(doc.display_url).to eq('https://example.com')
+      end
+    end
+
+    describe '#store_openai_file_id' do
+      it 'stores the file ID in metadata' do
+        pdf_document.save!
+        pdf_document.store_openai_file_id('file-abc123')
+
+        expect(pdf_document.reload.openai_file_id).to eq('file-abc123')
+      end
+    end
+
+    describe 'automatic external_link generation' do
+      it 'generates unique external_link for PDFs' do
+        pdf_document.external_link = nil
+        pdf_document.save!
+
+        expect(pdf_document.external_link).to start_with('PDF: test_')
+      end
+    end
+  end
+end

spec/enterprise/services/captain/llm/paginated_faq_generator_service_spec.rb

@@ -0,0 +1,106 @@
+require 'rails_helper'
+require 'custom_exceptions/pdf_processing_error'
+
+RSpec.describe Captain::Llm::PaginatedFaqGeneratorService do
+  let(:document) { create(:captain_document) }
+  let(:service) { described_class.new(document, pages_per_chunk: 5) }
+  let(:openai_client) { instance_double(OpenAI::Client) }
+
+  before do
+    # Mock OpenAI configuration
+    installation_config = instance_double(InstallationConfig, value: 'test-api-key')
+    allow(InstallationConfig).to receive(:find_by!)
+      .with(name: 'CAPTAIN_OPEN_AI_API_KEY')
+      .and_return(installation_config)
+
+    allow(OpenAI::Client).to receive(:new).and_return(openai_client)
+  end
+
+  describe '#generate' do
+    context 'when document lacks OpenAI file ID' do
+      before do
+        allow(document).to receive(:openai_file_id).and_return(nil)
+      end
+
+      it 'raises an error' do
+        expect { service.generate }.to raise_error(CustomExceptions::PdfFaqGenerationError)
+      end
+    end
+
+    context 'when generating FAQs from PDF pages' do
+      let(:faq_response) do
+        {
+          'choices' => [{
+            'message' => {
+              'content' => JSON.generate({
+                                           'faqs' => [
+                                             { 'question' => 'What is this document about?', 'answer' => 'It explains key concepts.' }
+                                           ],
+                                           'has_content' => true
+                                         })
+            }
+          }]
+        }
+      end
+
+      let(:empty_response) do
+        {
+          'choices' => [{
+            'message' => {
+              'content' => JSON.generate({
+                                           'faqs' => [],
+                                           'has_content' => false
+                                         })
+            }
+          }]
+        }
+      end
+
+      before do
+        allow(document).to receive(:openai_file_id).and_return('file-123')
+      end
+
+      it 'generates FAQs from paginated content' do
+        allow(openai_client).to receive(:chat).and_return(faq_response, empty_response)
+
+        faqs = service.generate
+
+        expect(faqs).to have_attributes(size: 1)
+        expect(faqs.first['question']).to eq('What is this document about?')
+      end
+
+      it 'stops when no more content' do
+        allow(openai_client).to receive(:chat).and_return(empty_response)
+
+        faqs = service.generate
+
+        expect(faqs).to be_empty
+      end
+
+      it 'respects max iterations limit' do
+        allow(openai_client).to receive(:chat).and_return(faq_response)
+
+        # Force max iterations
+        service.instance_variable_set(:@iterations_completed, 19)
+
+        service.generate
+        expect(service.iterations_completed).to eq(20)
+      end
+    end
+  end
+
+  describe '#should_continue_processing?' do
+    it 'stops at max iterations' do
+      service.instance_variable_set(:@iterations_completed, 20)
+      expect(service.should_continue_processing?(faqs: ['faq'], has_content: true)).to be false
+    end
+
+    it 'stops when no FAQs returned' do
+      expect(service.should_continue_processing?(faqs: [], has_content: true)).to be false
+    end
+
+    it 'continues when FAQs exist and under limits' do
+      expect(service.should_continue_processing?(faqs: ['faq'], has_content: true)).to be true
+    end
+  end
+end

spec/enterprise/services/captain/llm/pdf_processing_service_spec.rb

@@ -0,0 +1,58 @@
+require 'rails_helper'
+require 'custom_exceptions/pdf_processing_error'
+
+RSpec.describe Captain::Llm::PdfProcessingService do
+  let(:document) { create(:captain_document) }
+  let(:service) { described_class.new(document) }
+
+  before do
+    # Mock OpenAI configuration
+    installation_config = instance_double(InstallationConfig, value: 'test-api-key')
+    allow(InstallationConfig).to receive(:find_by!)
+      .with(name: 'CAPTAIN_OPEN_AI_API_KEY')
+      .and_return(installation_config)
+  end
+
+  describe '#process' do
+    context 'when document already has OpenAI file ID' do
+      before do
+        allow(document).to receive(:openai_file_id).and_return('existing-file-id')
+      end
+
+      it 'skips upload' do
+        expect(document).not_to receive(:store_openai_file_id)
+        service.process
+      end
+    end
+
+    context 'when uploading PDF to OpenAI' do
+      let(:mock_client) { instance_double(OpenAI::Client) }
+      let(:pdf_content) { 'PDF content' }
+
+      before do
+        allow(document).to receive(:openai_file_id).and_return(nil)
+
+        # Use a simple double for ActiveStorage since it's a complex Rails object
+        pdf_file = double('pdf_file', download: pdf_content) # rubocop:disable RSpec/VerifiedDoubles
+        allow(document).to receive(:pdf_file).and_return(pdf_file)
+
+        allow(OpenAI::Client).to receive(:new).and_return(mock_client)
+        # Use a simple double for OpenAI::Files as it may not be loaded
+        files_api = double('files_api') # rubocop:disable RSpec/VerifiedDoubles
+        allow(files_api).to receive(:upload).and_return({ 'id' => 'file-abc123' })
+        allow(mock_client).to receive(:files).and_return(files_api)
+      end
+
+      it 'uploads PDF and stores file ID' do
+        expect(document).to receive(:store_openai_file_id).with('file-abc123')
+        service.process
+      end
+
+      it 'raises error when upload fails' do
+        allow(mock_client.files).to receive(:upload).and_return({ 'id' => nil })
+
+        expect { service.process }.to raise_error(CustomExceptions::PdfUploadError)
+      end
+    end
+  end
+end

spec/fixtures/files/sample.pdf

@@ -0,0 +1,32 @@
+%PDF-1.4
+1 0 obj
+<< /Type /Catalog /Pages 2 0 R >>
+endobj
+2 0 obj
+<< /Type /Pages /Kids [3 0 R] /Count 1 >>
+endobj
+3 0 obj
+<< /Type /Page /Parent 2 0 R /Resources << /Font << /F1 << /Type /Font /Subtype /Type1 /BaseFont /Arial >> >> >> /MediaBox [0 0 612 792] /Contents 4 0 R >>
+endobj
+4 0 obj
+<< /Length 44 >>
+stream
+BT
+/F1 12 Tf
+100 700 Td
+(Sample PDF) Tj
+ET
+endstream
+endobj
+xref
+0 5
+0000000000 65535 f 
+0000000009 00000 n 
+0000000058 00000 n 
+0000000115 00000 n 
+0000000274 00000 n 
+trailer
+<< /Size 5 /Root 1 0 R >>
+startxref
+362
+%%EOF