fix(captain): log specific error handoff reason

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

@@ -179,7 +179,9 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
 
   def handle_error(error)
     log_error(error)
-    @response ||= { 'action_source' => 'error', 'action_reason' => 'response_builder_error' }
+    @response ||= {}
+    @response['action_source'] ||= 'error'
+    @response['action_reason'] ||= error_action_reason(error)
     process_v1_handoff if conversation_pending?
     true
   end
@@ -188,6 +190,10 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
     ChatwootExceptionTracker.new(error, account: account).capture_exception
   end
 
+  def error_action_reason(error)
+    error.class.name.underscore.tr('/', '_')
+  end
+
   def captain_v2_enabled?
     account.feature_enabled?('captain_integration_v2')
   end

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

@@ -398,9 +398,11 @@ RSpec.describe Captain::Conversation::ResponseBuilderJob, type: :job 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')
+        allow(Rails.logger).to receive(:info).and_call_original
 
         described_class.perform_now(conversation, assistant)
         expect(conversation.reload.status).to eq('open')
+        expect(Rails.logger).to have_received(:info).with(include('source=error reason=faraday_bad_request_error'))
       end
 
       it 'succeeds when no error occurs' do