track models that don't support functions

- raise error when adding functions and not supported

lib/chains/llm_chain.ex

@@ -117,6 +117,13 @@ defmodule LangChain.Chains.LLMChain do
   Add more functions to an LLMChain.
   """
   @spec add_functions(t(), Function.t() | [Function.t()]) :: t() | no_return()
+  def add_functions(
+        %LLMChain{llm: %{supports_functions: false}} = _chain,
+        _functions
+      ) do
+    raise LangChainError, "The LLM does not support functions."
+  end
+
   def add_functions(%LLMChain{} = chain, %Function{} = function) do
     add_functions(chain, [function])
   end

lib/chat_models/chat_bumble_model.ex → lib/chat_models/chat_bumblebee.ex

@@ -1,4 +1,4 @@
-defmodule LangChain.ChatModels.ChatBumbleModel do
+defmodule LangChain.ChatModels.ChatBumblebee do
   @moduledoc """
   Represents a chat model hosted and accessed through Bumblebee.
 
@@ -46,7 +46,7 @@ defmodule LangChain.ChatModels.ChatBumbleModel do
     field :stream, :boolean, default: true
   end
 
-  @type t :: %ChatBumbleModel{}
+  @type t :: %ChatBumblebee{}
 
   @type call_response :: {:ok, Message.t() | [Message.t()]} | {:error, String.t()}
   @type callback_data ::
@@ -72,18 +72,18 @@ defmodule LangChain.ChatModels.ChatBumbleModel do
   @text_end_tag "</s>"
 
   @doc """
-  Setup a ChatBumbleModel client configuration.
+  Setup a ChatBumblebee client configuration.
   """
   @spec new(attrs :: map()) :: {:ok, t} | {:error, Ecto.Changeset.t()}
   def new(%{} = attrs \\ %{}) do
-    %ChatBumbleModel{}
+    %ChatBumblebee{}
     |> cast(attrs, @create_fields)
     |> common_validation()
     |> apply_action(:insert)
   end
 
   @doc """
-  Setup a ChatBumbleModel client configuration and return it or raise an error if invalid.
+  Setup a ChatBumblebee client configuration and return it or raise an error if invalid.
   """
   @spec new!(attrs :: map()) :: t() | no_return()
   def new!(attrs \\ %{}) do
@@ -113,7 +113,7 @@ defmodule LangChain.ChatModels.ChatBumbleModel do
         ) :: call_response()
   def call(model, prompt, functions \\ [], callback_fn \\ nil)
 
-  def call(%ChatBumbleModel{} = model, prompt, functions, callback_fn) when is_binary(prompt) do
+  def call(%ChatBumblebee{} = model, prompt, functions, callback_fn) when is_binary(prompt) do
     messages = [
       Message.new_system!(),
       Message.new_user!(prompt)
@@ -122,7 +122,7 @@ defmodule LangChain.ChatModels.ChatBumbleModel do
     call(model, messages, functions, callback_fn)
   end
 
-  def call(%ChatBumbleModel{} = model, messages, functions, callback_fn)
+  def call(%ChatBumblebee{} = model, messages, functions, callback_fn)
       when is_list(messages) do
     if override_api_return?() do
       Logger.warning("Found override API response. Will not make live API call.")
@@ -176,7 +176,7 @@ defmodule LangChain.ChatModels.ChatBumbleModel do
   @spec do_serving_request(t(), [Message.t()], [Function.t()], callback_fn()) ::
           list() | struct() | {:error, String.t()}
   def do_serving_request(
-        %ChatBumbleModel{stream: false} = model,
+        %ChatBumblebee{stream: false} = model,
         messages,
         _functions,
         callback_fn
@@ -210,7 +210,7 @@ defmodule LangChain.ChatModels.ChatBumbleModel do
   end
 
   def do_serving_request(
-        %ChatBumbleModel{stream: true} = model,
+        %ChatBumblebee{stream: true} = model,
         messages,
         _functions,
         callback_fn
@@ -289,14 +289,14 @@ defmodule LangChain.ChatModels.ChatBumbleModel do
           data :: callback_data(),
           nil | callback_fn()
         ) :: :ok
-  defp fire_callback(%ChatBumbleModel{stream: true}, _data, nil) do
+  defp fire_callback(%ChatBumblebee{stream: true}, _data, nil) do
     Logger.warning("Streaming call requested but no callback function was given.")
     :ok
   end
 
-  defp fire_callback(%ChatBumbleModel{stream: false}, _data, nil), do: :ok
+  defp fire_callback(%ChatBumblebee{stream: false}, _data, nil), do: :ok
 
-  defp fire_callback(%ChatBumbleModel{}, data, callback_fn) when is_function(callback_fn) do
+  defp fire_callback(%ChatBumblebee{}, data, callback_fn) when is_function(callback_fn) do
     # OPTIONAL: Execute callback function
     callback_fn.(data)
     :ok

lib/chat_models/chat_open_ai.ex

@@ -52,6 +52,9 @@ defmodule LangChain.ChatModels.ChatOpenAI do
     field :n, :integer, default: 1
     field :json_response, :boolean, default: false
     field :stream, :boolean, default: false
+
+    # For compatibility between models, reflect that functions are supported
+    field :supports_functions, :boolean, default: true
   end
 
   @type t :: %ChatOpenAI{}

test/chains/llm_chain_test.exs

@@ -8,6 +8,7 @@ defmodule LangChain.Chains.LLMChainTest do
   alias LangChain.Function
   alias LangChain.Message
   alias LangChain.MessageDelta
+  alias LangChain.ChatModels.ChatBumblebee
 
   setup do
     {:ok, chat} = ChatOpenAI.new(%{temperature: 0})
@@ -71,6 +72,13 @@ defmodule LangChain.Chains.LLMChainTest do
       assert updated_chain2.functions == [function, howdy_fn]
       assert updated_chain2.function_map == %{"hello_world" => function, "howdy" => howdy_fn}
     end
+
+    test "raises an exception when the model does not support functions" do
+      chain = LLMChain.new!(%{llm: %ChatBumblebee{supports_functions: false}})
+      assert_raise LangChain.LangChainError, "The LLM does not support functions.", fn ->
+        LLMChain.add_functions(chain, Function.new!(%{name: "test"}))
+      end
+    end
   end
 
   describe "cancelled_delta/1" do