Refactor assistant determine tool role method (#823)

* Fix merge conflicts

* Teeny adapter_spec file

* Fixes

* Remove `Langchain::Assistant#clear_thread!` method

* CHANGELOG entry

Author: andreibondarev

CHANGELOG.md

@@ -1,6 +1,8 @@
 ## [Unreleased]
+- [BREAKING] Remove `Langchain::Assistant#clear_thread!` method
 - [BREAKING] `Langchain::Messages::*` namespace had migrated to `Langchain::Assistant::Messages::*`
 - [BREAKING] Modify `Langchain::LLM::AwsBedrock` constructor to pass model options via default_options: {...}
+- Minor improvements to the Langchain::Assistant class
 - Added support for streaming with Anthropic
 - Bump anthropic gem
 - Default Langchain::LLM::Anthropic chat model is "claude-3-5-sonnet-20240620" now

lib/langchain/assistant.rb

@@ -165,10 +165,8 @@ def add_message_and_run!(content: nil, image_url: nil)
     # @param output [String] The output of the tool
     # @return [Array<Langchain::Message>] The messages
     def submit_tool_output(tool_call_id:, output:)
-      tool_role = determine_tool_role
-
       # TODO: Validate that `tool_call_id` is valid by scanning messages and checking if this tool call ID was invoked
-      add_message(role: tool_role, content: output, tool_call_id: tool_call_id)
+      add_message(role: @llm_adapter.tool_role, content: output, tool_call_id: tool_call_id)
     end
 
     # Delete all messages
@@ -179,9 +177,6 @@ def clear_messages!
       @messages = []
     end
 
-    # TODO: Remove in the next major release
-    alias_method :clear_thread!, :clear_messages!
-
     # Set new instructions
     #
     # @param new_instructions [String] New instructions that will be set as a system message
@@ -328,24 +323,6 @@ def execute_tools
       :failed
     end
 
-    # Determine the tool role based on the LLM type
-    #
-    # @return [String] The tool role
-    def determine_tool_role
-      case llm
-      when Langchain::LLM::Anthropic
-        Messages::AnthropicMessage::TOOL_ROLE
-      when Langchain::LLM::GoogleGemini, Langchain::LLM::GoogleVertexAI
-        Messages::GoogleGeminiMessage::TOOL_ROLE
-      when Langchain::LLM::MistralAI
-        Messages::MistralAIMessage::TOOL_ROLE
-      when Langchain::LLM::Ollama
-        Messages::OllamaMessage::TOOL_ROLE
-      when Langchain::LLM::OpenAI
-        Messages::OpenAIMessage::TOOL_ROLE
-      end
-    end
-
     def initialize_instructions
       if llm.is_a?(Langchain::LLM::OpenAI) || llm.is_a?(Langchain::LLM::MistralAI)
         self.instructions = @instructions if @instructions

lib/langchain/assistant/llm/adapters/anthropic.rb

@@ -66,6 +66,10 @@ def available_tool_names(tools)
             build_tools(tools).map { |tool| tool.dig(:name) }
           end
 
+          def tool_role
+            Messages::AnthropicMessage::TOOL_ROLE
+          end
+
           private
 
           def build_tool_choice(choice)

lib/langchain/assistant/llm/adapters/base.rb

@@ -35,6 +35,13 @@ def extract_tool_call_args(tool_call:)
           def build_message(role:, content: nil, image_url: nil, tool_calls: [], tool_call_id: nil)
             raise NotImplementedError, "Subclasses must implement build_message"
           end
+
+          # Role name used to return the tool output
+          #
+          # @return [String] The tool role
+          def tool_role
+            raise NotImplementedError, "Subclasses must implement tool_role"
+          end
         end
       end
     end

lib/langchain/assistant/llm/adapters/google_gemini.rb

@@ -66,6 +66,10 @@ def available_tool_names(tools)
             build_tools(tools).map { |tool| tool.dig(:name) }
           end
 
+          def tool_role
+            Messages::GoogleGeminiMessage::TOOL_ROLE
+          end
+
           private
 
           def build_tool_config(choice)

lib/langchain/assistant/llm/adapters/mistral_ai.rb

@@ -68,6 +68,10 @@ def available_tool_names(tools)
             build_tools(tools).map { |tool| tool.dig(:function, :name) }
           end
 
+          def tool_role
+            Messages::MistralAIMessage::TOOL_ROLE
+          end
+
           private
 
           def build_tool_choice(choice)

lib/langchain/assistant/llm/adapters/ollama.rb

@@ -64,6 +64,10 @@ def allowed_tool_choices
             ["auto", "none"]
           end
 
+          def tool_role
+            Messages::OllamaMessage::TOOL_ROLE
+          end
+
           private
 
           def build_tools(tools)

lib/langchain/assistant/llm/adapters/openai.rb

@@ -68,6 +68,10 @@ def available_tool_names(tools)
             build_tools(tools).map { |tool| tool.dig(:function, :name) }
           end
 
+          def tool_role
+            Messages::OpenAIMessage::TOOL_ROLE
+          end
+
           private
 
           def build_tool_choice(choice)

spec/langchain/assistant/llm/adapter_spec.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+RSpec.describe Langchain::Assistant::LLM::Adapter do
+  let(:llm) { Langchain::LLM::OpenAI.new(api_key: "123") }
+
+  it "initialize a new OpenAI adapter" do
+    expect(described_class.build(llm)).to be_a(Langchain::Assistant::LLM::Adapters::OpenAI)
+  end
+end