FEATURE: Truncate AI Captions to a reasonable max size (#907)

lib/ai_helper/assistant.rb

@@ -3,6 +3,8 @@
 module DiscourseAi
   module AiHelper
     class Assistant
+      IMAGE_CAPTION_MAX_WORDS = 50
+
       def self.prompt_cache
         @prompt_cache ||= ::DiscourseAi::MultisiteHash.new("prompt_cache")
       end
@@ -164,7 +166,7 @@ module DiscourseAi
             feature_name: "image_caption",
           )
 
-        raw_caption.delete("|").squish
+        raw_caption.delete("|").squish.truncate_words(IMAGE_CAPTION_MAX_WORDS)
       end
 
       private

spec/requests/ai_helper/assistant_controller_spec.rb

@@ -163,6 +163,13 @@ RSpec.describe DiscourseAi::AiHelper::AssistantController do
         end
       end
 
+      it "truncates the caption from the LLM" do
+        request_caption({ image_url: image_url, image_url_type: "long_url" }, caption * 10) do |r|
+          expect(r.status).to eq(200)
+          expect(r.parsed_body["caption"].size).to be < caption.size * 10
+        end
+      end
+
       context "when the image_url is a short_url" do
         let(:image_url) { upload.short_url }