FIX: properly truncate !command prompts (#227)

* FIX: properly truncate !command prompts

### What is going on here?

Previous to this change where a command was issued by the LLM it
could hallucinate a continuation eg:

```
This is what tags are

!tags

some nonsense here
```

This change introduces safeguards so `some nonsense here` does not
creep in to the prompt history, poisoning the llm results

This in effect grounds the llm a lot better and results in the llm
forgetting less about results.

The change only impacts Claude at the moment, but will also improve
stuff for llama 2 in future.

Also, this makes it significantly easier to test the bot framework
without an llm cause we avoid a whole bunch of complex stubbing

* blank is not a valid bot response, do not inject into prompt

lib/modules/ai_bot/bot.rb

@@ -47,6 +47,24 @@ module DiscourseAi
         def to_a
           @functions
         end
+
+        def truncate(partial_reply)
+          lines = []
+          found_command = false
+          partial_reply
+            .split("\n")
+            .each do |line|
+              if line.match?(/^!/)
+                found_command = true
+                lines << line
+              elsif found_command && line.match(/^\s*[^!]+/)
+                break
+              else
+                lines << line
+              end
+            end
+          lines.join("\n")
+        end
       end
 
       attr_reader :bot_user
@@ -142,7 +160,6 @@ module DiscourseAi
             bot_reply_post.update!(raw: reply, cooked: PrettyText.cook(reply)) if bot_reply_post
           end
 
-          next if reply.length < SiteSetting.min_personal_message_post_length
           # Minor hack to skip the delay during tests.
           next if (Time.now - start < 0.5) && !Rails.env.test?
 
@@ -157,7 +174,7 @@ module DiscourseAi
                 bot_user,
                 topic_id: post.topic_id,
                 raw: reply,
-                skip_validations: false,
+                skip_validations: true,
               )
           end
 
@@ -181,7 +198,14 @@ module DiscourseAi
           bot_reply_post.post_custom_prompt ||= post.build_post_custom_prompt(custom_prompt: [])
           prompt = post.post_custom_prompt.custom_prompt || []
 
-          prompt << [partial_reply, bot_user.username]
+          truncated_reply = partial_reply
+
+          if functions.found? && functions.cancel_completion?
+            # we need to truncate the partial_reply
+            truncated_reply = functions.truncate(partial_reply)
+          end
+
+          prompt << [truncated_reply, bot_user.username] if truncated_reply.present?
 
           post.post_custom_prompt.update!(custom_prompt: prompt)
         end
@@ -321,10 +345,10 @@ module DiscourseAi
 
       def populate_functions(partial:, reply:, functions:, done:)
         if !done
+          functions.found! if reply.match?(/^!/i)
           if functions.found?
             functions.cancel_completion! if reply.split("\n")[-1].match?(/^\s*[^!]+/)
           end
-          functions.found! if reply.match?(/^!/i)
         else
           reply
             .scan(/^!.*$/i)

lib/shared/inference/function_list.rb

@@ -27,6 +27,8 @@ module ::DiscourseAi
             function = @functions.find { |f| f.name == name }
             next if function.blank?
 
+            parsed_arguments = {}
+            if arguments
               arguments = arguments[0..-2] if arguments.end_with?(")")
 
               temp_string = +""
@@ -45,7 +47,6 @@ module ::DiscourseAi
 
               arguments = temp_string.split(",").map { |s| s.gsub(replace, ",").strip }
 
-            parsed_arguments = {}
               arguments.each do |argument|
                 key, value = argument.split(":", 2)
                 # remove stuff that is bypasses spec
@@ -60,6 +61,7 @@ module ::DiscourseAi
 
                 parsed_arguments[key.strip.to_sym] = value.strip
               end
+            end
 
             # ensure parsed_arguments has all required arguments
             all_good = true

spec/lib/modules/ai_bot/bot_spec.rb

@@ -2,7 +2,82 @@
 
 require_relative "../../../support/openai_completions_inference_stubs"
 
-RSpec.describe DiscourseAi::AiBot::Bot do
+class FakeBot < DiscourseAi::AiBot::Bot
+  class Tokenizer
+    def tokenize(text)
+      text.split(" ")
+    end
+  end
+
+  def tokenizer
+    Tokenizer.new
+  end
+
+  def prompt_limit
+    10_000
+  end
+
+  def build_message(poster_username, content, system: false, function: nil)
+    role = poster_username == bot_user.username ? "Assistant" : "Human"
+
+    "#{role}: #{content}"
+  end
+
+  def submit_prompt(prompt, prefer_low_cost: false)
+    rows = @responses.shift
+    rows.each { |data| yield data, lambda {} }
+  end
+
+  def get_delta(partial, context)
+    partial
+  end
+
+  def add_response(response)
+    @responses ||= []
+    @responses << response
+  end
+end
+
+describe FakeBot do
+  fab!(:bot_user) { User.find(DiscourseAi::AiBot::EntryPoint::GPT4_ID) }
+  fab!(:post) { Fabricate(:post, raw: "hello world") }
+
+  it "can handle command truncation for long messages" do
+    bot = FakeBot.new(bot_user)
+
+    bot.add_response(["hello this is a big test I am testing 123\n", "!tags\nabc"])
+    bot.add_response(["this is the reply"])
+
+    bot.reply_to(post)
+
+    reply = post.topic.posts.order(:post_number).last
+
+    expect(reply.raw).not_to include("abc")
+    expect(reply.post_custom_prompt.custom_prompt.to_s).not_to include("abc")
+    expect(reply.post_custom_prompt.custom_prompt.length).to eq(3)
+    expect(reply.post_custom_prompt.custom_prompt[0][0]).to eq(
+      "hello this is a big test I am testing 123\n!tags",
+    )
+  end
+
+  it "can handle command truncation for short bot messages" do
+    bot = FakeBot.new(bot_user)
+
+    bot.add_response(["hello\n", "!tags\nabc"])
+    bot.add_response(["this is the reply"])
+
+    bot.reply_to(post)
+
+    reply = post.topic.posts.order(:post_number).last
+
+    expect(reply.raw).not_to include("abc")
+    expect(reply.post_custom_prompt.custom_prompt.to_s).not_to include("abc")
+    expect(reply.post_custom_prompt.custom_prompt.length).to eq(3)
+    expect(reply.post_custom_prompt.custom_prompt[0][0]).to eq("hello\n!tags")
+  end
+end
+
+describe DiscourseAi::AiBot::Bot do
   fab!(:bot_user) { User.find(DiscourseAi::AiBot::EntryPoint::GPT4_ID) }
   fab!(:bot) { described_class.as(bot_user) }