Fixed Calling chat.to_llm keeps appending messages to the message array

Closes #145

Author: crmne

lib/ruby_llm/active_record/acts_as.rb

@@ -67,6 +67,7 @@ module ChatMethods
 
       def to_llm
         @chat ||= RubyLLM.chat(model: model_id)
+        @chat.reset_messages!
 
         # Load existing messages into chat
         messages.each do |msg|

lib/ruby_llm/chat.rb

@@ -110,6 +110,10 @@ def add_message(message_or_attributes)
       message
     end
 
+    def reset_messages!
+      @messages.clear
+    end
+
     private
 
     def handle_tool_calls(response, &)

spec/ruby_llm/active_record/acts_as_spec.rb

@@ -99,6 +99,19 @@ def execute(expression:)
     expect(chat.messages.last.output_tokens).to be_positive
   end
 
+  it 'to_llm returns the correct amount of messages' do # rubocop:disable RSpec/MultipleExpectations,RSpec/ExampleLength
+    chat = Chat.create!(model_id: 'gpt-4.1-nano')
+    chat.ask("What's your favorite Ruby feature?")
+
+    expect(chat.messages.count).to eq(2)
+    expect(chat.to_llm.messages.count).to eq(2)
+
+    chat.ask('Again?')
+
+    expect(chat.messages.count).to eq(4)
+    expect(chat.to_llm.messages.count).to eq(4)
+  end
+
   it 'persists tool calls' do # rubocop:disable RSpec/MultipleExpectations
     chat = Chat.create!(model_id: 'gpt-4.1-nano')
     chat.with_tool(Calculator)