fix: captain json parsing (#13708)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Shivam Mishra <scm.mymail@gmail.com>

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

@@ -1,5 +1,6 @@
 class Captain::Llm::ContactAttributesService < Llm::BaseAiService
   include Integrations::LlmInstrumentation
+
   def initialize(assistant, conversation)
     super()
     @assistant = assistant
@@ -52,7 +53,7 @@ class Captain::Llm::ContactAttributesService < Llm::BaseAiService
   def parse_response(content)
     return [] if content.nil?
 
-    JSON.parse(content.strip).fetch('attributes', [])
+    JSON.parse(sanitize_json_response(content)).fetch('attributes', [])
   rescue JSON::ParserError => e
     Rails.logger.error "Error in parsing GPT processed response: #{e.message}"
     []

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

@@ -1,5 +1,6 @@
 class Captain::Llm::ContactNotesService < Llm::BaseAiService
   include Integrations::LlmInstrumentation
+
   def initialize(assistant, conversation)
     super()
     @assistant = assistant
@@ -55,7 +56,7 @@ class Captain::Llm::ContactNotesService < Llm::BaseAiService
   def parse_response(response)
     return [] if response.nil?
 
-    JSON.parse(response.strip).fetch('notes', [])
+    JSON.parse(sanitize_json_response(response)).fetch('notes', [])
   rescue JSON::ParserError => e
     Rails.logger.error "Error in parsing GPT processed response: #{e.message}"
     []

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

@@ -1,5 +1,6 @@
 class Captain::Llm::ConversationFaqService < Llm::BaseAiService
   include Integrations::LlmInstrumentation
+
   DISTANCE_THRESHOLD = 0.3
 
   def initialize(assistant, conversation)
@@ -118,7 +119,7 @@ class Captain::Llm::ConversationFaqService < Llm::BaseAiService
   def parse_response(response)
     return [] if response.nil?
 
-    JSON.parse(response.strip).fetch('faqs', [])
+    JSON.parse(sanitize_json_response(response)).fetch('faqs', [])
   rescue JSON::ParserError => e
     Rails.logger.error "Error in parsing GPT processed response: #{e.message}"
     []

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

@@ -47,7 +47,7 @@ class Captain::Llm::FaqGeneratorService < Llm::BaseAiService
   def parse_response(content)
     return [] if content.nil?
 
-    JSON.parse(content.strip).fetch('faqs', [])
+    JSON.parse(sanitize_json_response(content)).fetch('faqs', [])
   rescue JSON::ParserError => e
     Rails.logger.error "Error in parsing GPT processed response: #{e.message}"
     []

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

@@ -163,7 +163,7 @@ class Captain::Llm::PaginatedFaqGeneratorService < Llm::LegacyBaseOpenAiService
     content = response.dig('choices', 0, 'message', 'content')
     return [] if content.nil?
 
-    JSON.parse(content.strip).fetch('faqs', [])
+    JSON.parse(sanitize_json_response(content)).fetch('faqs', [])
   rescue JSON::ParserError => e
     Rails.logger.error "Error parsing response: #{e.message}"
     []
@@ -173,7 +173,7 @@ class Captain::Llm::PaginatedFaqGeneratorService < Llm::LegacyBaseOpenAiService
     content = response.dig('choices', 0, 'message', 'content')
     return { 'faqs' => [], 'has_content' => false } if content.nil?
 
-    JSON.parse(content.strip)
+    JSON.parse(sanitize_json_response(content))
   rescue JSON::ParserError => e
     Rails.logger.error "Error parsing chunk response: #{e.message}"
     { 'faqs' => [], 'has_content' => false }

enterprise/app/services/llm/base_ai_service.rb

@@ -20,6 +20,14 @@ class Llm::BaseAiService
 
   private
 
+  # Strips markdown code fences (```json ... ``` or ``` ... ```) that some
+  # LLM providers/gateways wrap around JSON responses despite response_format hints.
+  def sanitize_json_response(response)
+    return response if response.nil?
+
+    response.strip.sub(/\A```(?:\w*)\s*\n?/, '').sub(/\n?\s*```\s*\z/, '').strip
+  end
+
   def setup_model
     config_value = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_MODEL')&.value
     @model = (config_value.presence || DEFAULT_MODEL)

enterprise/app/services/llm/legacy_base_open_ai_service.rb

@@ -24,6 +24,14 @@ class Llm::LegacyBaseOpenAiService
 
   private
 
+  # Strips markdown code fences (```json ... ``` or ``` ... ```) that some
+  # LLM providers/gateways wrap around JSON responses despite response_format hints.
+  def sanitize_json_response(response)
+    return response if response.nil?
+
+    response.strip.sub(/\A```(?:\w*)\s*\n?/, '').sub(/\n?\s*```\s*\z/, '').strip
+  end
+
   def uri_base
     endpoint = InstallationConfig.find_by(name: 'CAPTAIN_OPEN_AI_ENDPOINT')&.value
     endpoint.presence || 'https://api.openai.com/'

spec/enterprise/services/llm/base_ai_service_spec.rb

@@ -0,0 +1,35 @@
+require 'rails_helper'
+
+RSpec.describe Llm::BaseAiService do
+  subject(:service) { described_class.new }
+
+  before do
+    create(:installation_config, name: 'CAPTAIN_OPEN_AI_API_KEY', value: 'test-key')
+  end
+
+  describe '#sanitize_json_response' do
+    it 'strips ```json fences' do
+      input = "```json\n{\"key\": \"value\"}\n```"
+      expect(service.send(:sanitize_json_response, input)).to eq('{"key": "value"}')
+    end
+
+    it 'strips bare ``` fences' do
+      input = "```\n{\"key\": \"value\"}\n```"
+      expect(service.send(:sanitize_json_response, input)).to eq('{"key": "value"}')
+    end
+
+    it 'passes through plain JSON unchanged' do
+      input = '{"key": "value"}'
+      expect(service.send(:sanitize_json_response, input)).to eq('{"key": "value"}')
+    end
+
+    it 'returns nil for nil input' do
+      expect(service.send(:sanitize_json_response, nil)).to be_nil
+    end
+
+    it 'strips surrounding whitespace' do
+      input = "  \n{\"key\": \"value\"}\n  "
+      expect(service.send(:sanitize_json_response, input)).to eq('{"key": "value"}')
+    end
+  end
+end