FEATURE: Use personas for generating hypothetical posts

config/locales/client.en.yml

@@ -222,6 +222,10 @@ en:
           name: "Search"
           description: "Enhances search experience by providing AI-generated answers to queries"
           discoveries: "Discoveries"
+        embeddings:
+          name: "Embeddings"
+          description: "Powers features like Related Topics and AI Search by generating semantic representations of text"
+          hyde: "HyDE"
         discord:
           name: "Discord integration"
           description: "Adds the ability to search Discord channels"

config/locales/server.en.yml

@@ -394,6 +394,9 @@ en:
         spam_detector:
           name: "Spam detector"
           description: "Default persona powering our Spam detection feature"
+        content_creator:
+          name: "Content creator"
+          description: "Default persona powering HyDE search"
 
       topic_not_found: "Summary unavailable, topic not found!"
       summarizing: "Summarizing topic"

config/settings.yml

@@ -222,34 +222,45 @@ discourse_ai:
     default: false
     client: true
     validator: "DiscourseAi::Configuration::EmbeddingsModuleValidator"
+    area: "ai-features/embeddings"
   ai_embeddings_selected_model:
     type: enum
     default: ""
     allow_any: false
     enum: "DiscourseAi::Configuration::EmbeddingDefsEnumerator"
     validator: "DiscourseAi::Configuration::EmbeddingDefsValidator"
+    area: "ai-features/embeddings"
   ai_embeddings_per_post_enabled:
     default: false
     hidden: true
-  ai_embeddings_generate_for_pms: false
+  ai_embeddings_generate_for_pms: 
+    default: false
+    area: "ai-features/embeddings"
   ai_embeddings_semantic_related_topics_enabled:
     default: false
     client: true
-  ai_embeddings_semantic_related_topics: 5
-  ai_embeddings_semantic_related_include_closed_topics: true
+    area: "ai-features/embeddings"
+  ai_embeddings_semantic_related_topics: 
+    default: 5
+    area: "ai-features/embeddings"
+  ai_embeddings_semantic_related_include_closed_topics: 
+    default: true
+    area: "ai-features/embeddings"
   ai_embeddings_backfill_batch_size:
     default: 250
     hidden: true
   ai_embeddings_semantic_search_enabled:
     default: false
     client: true
     validator: "DiscourseAi::Configuration::LlmDependencyValidator"
+    area: "ai-features/embeddings"
   ai_embeddings_semantic_search_hyde_model:
     default: ""
     type: enum
     allow_any: false
     enum: "DiscourseAi::Configuration::LlmEnumerator"
     validator: "DiscourseAi::Configuration::LlmValidator"
+    area: "ai-features/embeddings"
   ai_embeddings_semantic_search_hyde_model_allowed_seeded_models:
     default: ""
     hidden: true
@@ -259,6 +270,12 @@ discourse_ai:
     default: false
     client: true
     hidden: true
+    area: "ai-features/embeddings"
+  ai_embeddings_semantic_search_hyde_persona:
+    default: "-32"
+    type: enum
+    enum: "DiscourseAi::Configuration::PersonaEnumerator"
+    area: "ai-features/embeddings"
 
   ai_embeddings_discourse_service_api_endpoint:
     default: ""

db/fixtures/personas/603_ai_personas.rb

@@ -36,6 +36,8 @@ def from_setting(setting_name)
       setting_name = "ai_helper_custom_prompts_allowed_groups"
       default_groups = [Group::AUTO_GROUPS[:staff]]
       persona.allowed_group_ids = from_setting(setting_name) || default_groups
+    elsif persona_class == DiscourseAi::Personas::ContentCreator
+      persona.allowed_group_ids = [Group::AUTO_GROUPS[:everyone]]
     else
       persona.allowed_group_ids = [Group::AUTO_GROUPS[:trust_level_0]]
     end

lib/configuration/feature.rb

@@ -144,6 +144,17 @@ def spam_features
           ]
         end
 
+        def embeddings_features
+          feature_cache[:embeddings] ||= [
+            new(
+              "hyde",
+              "ai_embeddings_semantic_search_hyde_persona",
+              DiscourseAi::Configuration::Module::EMBEDDINGS_ID,
+              DiscourseAi::Configuration::Module::EMBEDDINGS,
+            ),
+          ]
+        end
+
         def lookup_bot_persona_ids
           AiPersona
             .where(enabled: true)
@@ -196,6 +207,7 @@ def all
             translation_features,
             bot_features,
             spam_features,
+            embeddings_features,
           ].flatten
         end
 
@@ -241,6 +253,8 @@ def llm_models
               DiscourseAi::AiHelper::Assistant.find_ai_helper_model(name, persona_klass)
             when DiscourseAi::Configuration::Module::TRANSLATION
               DiscourseAi::Translation::BaseTranslator.preferred_llm_model(persona_klass)
+            when DiscourseAi::Configuration::Module::EMBEDDINGS
+              DiscourseAi::Embeddings::SemanticSearch.new(nil).find_ai_hyde_model(persona_klass)
             end
 
           if llm_model.blank? && persona.default_llm_id

lib/configuration/module.rb

@@ -11,8 +11,19 @@ class Module
       TRANSLATION = "translation"
       BOT = "bot"
       SPAM = "spam"
+      EMBEDDINGS = "embeddings"
 
-      NAMES = [SUMMARIZATION, SEARCH, DISCORD, INFERENCE, AI_HELPER, TRANSLATION, BOT, SPAM].freeze
+      NAMES = [
+        SUMMARIZATION,
+        SEARCH,
+        DISCORD,
+        INFERENCE,
+        AI_HELPER,
+        TRANSLATION,
+        BOT,
+        SPAM,
+        EMBEDDINGS,
+      ].freeze
 
       SUMMARIZATION_ID = 1
       SEARCH_ID = 2
@@ -22,6 +33,7 @@ class Module
       TRANSLATION_ID = 6
       BOT_ID = 7
       SPAM_ID = 8
+      EMBEDDINGS_ID = 9
 
       class << self
         def all
@@ -75,6 +87,13 @@ def all
               enabled_by_setting: "ai_spam_detection_enabled",
               features: DiscourseAi::Configuration::Feature.spam_features,
             ),
+            new(
+              EMBEDDINGS_ID,
+              EMBEDDINGS,
+              enabled_by_setting: "ai_embeddings_enabled",
+              features: DiscourseAi::Configuration::Feature.embeddings_features,
+              extra_check: -> { SiteSetting.ai_embeddings_semantic_search_enabled },
+            ),
           ]
         end
 

lib/embeddings/semantic_search.rb

@@ -78,7 +78,9 @@ def search_for_topics(query, page = 1, hyde: true)
           return Post.none
         end
 
-        search_embedding = hyde ? hyde_embedding(search_term) : embedding(search_term)
+        search_embedding = nil
+        search_embedding = hyde_embedding(search_term) if hyde
+        search_embedding = embedding(search_term) if search_embedding.blank?
 
         over_selection_limit = limit * OVER_SELECTION_FACTOR
 
@@ -176,26 +178,51 @@ def quick_search(query)
       end
 
       def hypothetical_post_from(search_term)
-        prompt = DiscourseAi::Completions::Prompt.new(<<~TEXT.strip)
-          You are a content creator for a forum. The forum description is as follows:
-          #{SiteSetting.title}
-          #{SiteSetting.site_description}
+        context =
+          DiscourseAi::Personas::BotContext.new(
+            user: @guardian.user,
+            skip_tool_details: true,
+            feature_name: "semantic_search_hyde",
+            messages: [{ type: :user, content: <<~TEXT.strip }],
+              Using this description, write a forum post about the subject inside the <input></input> XML tags:
+
+              <input>#{search_term}</input>
+            TEXT
+          )
 
-          Put the forum post between <ai></ai> tags.
-        TEXT
+        bot = build_bot(@guardian.user)
+        return nil if bot.nil?
 
-        prompt.push(type: :user, content: <<~TEXT.strip)
-          Using this description, write a forum post about the subject inside the <input></input> XML tags:
+        structured_output = nil
+        raw_response = +""
+        hyde_schema_key = bot.persona.response_format&.first.to_h
 
-          <input>#{search_term}</input>
-        TEXT
+        buffer_blk =
+          Proc.new do |partial, _, type|
+            if type == :structured_output
+              structured_output = partial
+            elsif type.blank?
+              # Assume response is a regular completion.
+              raw_response << partial
+            end
+          end
 
-        llm_response =
-          DiscourseAi::Completions::Llm.proxy(
-            SiteSetting.ai_embeddings_semantic_search_hyde_model,
-          ).generate(prompt, user: @guardian.user, feature_name: "semantic_search_hyde")
+        bot.reply(context, &buffer_blk)
+
+        structured_output&.read_buffered_property(hyde_schema_key["key"]&.to_sym) || raw_response
+      end
+
+      # Priorities are:
+      #   1. Persona's default LLM
+      #   2. `ai_embeddings_semantic_search_hyde_model` setting.
+      def find_ai_hyde_model(persona_klass)
+        model_id =
+          persona_klass.default_llm_id ||
+            SiteSetting.ai_embeddings_semantic_search_hyde_model&.split(":")&.last
 
-        Nokogiri::HTML5.fragment(llm_response).at("ai")&.text.presence || llm_response
+        return if model_id.blank?
+
+        LlmModel.find_by(id: model_id)
       end
 
       private
@@ -209,6 +236,18 @@ def build_hyde_key(digest, hyde_model)
       def build_embedding_key(digest, hyde_model, embedding_model)
         "#{build_hyde_key(digest, hyde_model)}-#{embedding_model}"
       end
+
+      def build_bot(user)
+        persona_id = SiteSetting.ai_embeddings_semantic_search_hyde_persona
+
+        persona_klass = AiPersona.find_by(id: persona_id)&.class_instance
+        return if persona_klass.nil?
+
+        llm_model = find_ai_hyde_model(persona_klass)
+        return if llm_model.nil?
+
+        DiscourseAi::Personas::Bot.as(user, persona: persona_klass.new, model: llm_model)
+      end
     end
   end
 end

lib/personas/bot.rb

@@ -171,7 +171,7 @@ def reply(context, llm_args: {}, &update_blk)
               text = +""
               result.each { |item| text << item if item.is_a?(String) }
             end
-            raw_context << [text, bot_user.username]
+            raw_context << [text, bot_user&.username]
           end
 
           total_completions += 1

lib/personas/content_creator.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Personas
+    class ContentCreator < Persona
+      def self.default_enabled
+        false
+      end
+
+      def system_prompt
+        <<~PROMPT.strip
+          You are a content creator for a forum. The forum title and description is as follows:
+          * Ttitle: {site_title}
+          * Description: {site_description}
+
+          Format your response as a JSON object with a single key named "output", which has the created content.
+          Your output should be in the following format:
+            <output>
+              {"output": "xx"}
+            </output>
+
+          Where "xx" is replaced by the content.
+        PROMPT
+      end
+
+      def response_format
+        [{ "key" => "output", "type" => "string" }]
+      end
+    end
+  end
+end

lib/personas/persona.rb

@@ -69,6 +69,7 @@ def system_personas
             TopicTitleTranslator => -29,
             ShortTextTranslator => -30,
             SpamDetector => -31,
+            ContentCreator => -32,
           }
         end
 

spec/lib/modules/embeddings/semantic_search_spec.rb

@@ -27,7 +27,7 @@ def insert_candidate(candidate)
     end
 
     def trigger_search(query)
-      DiscourseAi::Completions::Llm.with_prepared_responses(["<ai>#{hypothetical_post}</ai>"]) do
+      DiscourseAi::Completions::Llm.with_prepared_responses([hypothetical_post]) do
         subject.search_for_topics(query)
       end
     end
@@ -123,9 +123,9 @@ def trigger_search(query)
         context "while searching as anon" do
           it "returns an empty list" do
             posts =
-              DiscourseAi::Completions::Llm.with_prepared_responses(
-                ["<ai>#{hypothetical_post}</ai>"],
-              ) { described_class.new(Guardian.new(nil)).search_for_topics(query) }
+              DiscourseAi::Completions::Llm.with_prepared_responses([hypothetical_post]) do
+                described_class.new(Guardian.new(nil)).search_for_topics(query)
+              end
 
             expect(posts).to be_empty
           end

spec/lib/personas/tools/search_spec.rb

@@ -125,7 +125,7 @@
         DiscourseAi::Embeddings::Schema.for(Topic).store(post1.topic, hyde_embedding, "digest")
 
         results =
-          DiscourseAi::Completions::Llm.with_prepared_responses(["<ai>#{query}</ai>"]) do
+          DiscourseAi::Completions::Llm.with_prepared_responses([query]) do
             search.invoke(&progress_blk)
           end
 
@@ -144,7 +144,7 @@
 
         # results will be expanded by semantic search, but it will find nothing
         results =
-          DiscourseAi::Completions::Llm.with_prepared_responses(["<ai>#{query}</ai>"]) do
+          DiscourseAi::Completions::Llm.with_prepared_responses([query]) do
             search.invoke(&progress_blk)
           end
 

spec/lib/utils/search_spec.rb

@@ -154,7 +154,7 @@
 
         # Using a completely different search query, should still find via semantic search
         results =
-          DiscourseAi::Completions::Llm.with_prepared_responses(["<ai>#{query}</ai>"]) do
+          DiscourseAi::Completions::Llm.with_prepared_responses([query]) do
             described_class.perform_search(
               search_query: "totally different query",
               current_user: admin,

spec/requests/admin/ai_features_controller_spec.rb

@@ -19,7 +19,7 @@
       get "/admin/plugins/discourse-ai/ai-features.json"
 
       expect(response.status).to eq(200)
-      expect(response.parsed_body["ai_features"].count).to eq(8)
+      expect(response.parsed_body["ai_features"].count).to eq(9)
     end
   end
 

spec/system/admin_ai_features_spec.rb

@@ -28,7 +28,7 @@
     ai_features_page.toggle_unconfigured
 
     # this changes as we add more AI features
-    expect(ai_features_page).to have_listed_modules(7)
+    expect(ai_features_page).to have_listed_modules(8)
   end
 
   it "lists the persona used for the corresponding AI feature" do