update signature in core

libs/core/langchain_core/language_models/base.py

@@ -364,13 +364,22 @@ class BaseLanguageModel(
         """
         return len(self.get_token_ids(text))
 
-    def get_num_tokens_from_messages(self, messages: list[BaseMessage]) -> int:
+    def get_num_tokens_from_messages(
+        self,
+        messages: list[BaseMessage],
+        tools: Optional[Sequence] = None,
+    ) -> int:
         """Get the number of tokens in the messages.
 
         Useful for checking if an input fits in a model's context window.
 
+        **Note**: the base implementation of get_num_tokens_from_messages ignores
+        tool schemas.
+
         Args:
             messages: The message inputs to tokenize.
+            tools: If provided, sequence of dict, BaseModel, function, or BaseTools
+                to be converted to tool schemas.
 
         Returns:
             The sum of the number of tokens across the messages.

libs/core/tests/unit_tests/messages/test_utils.py

@@ -1,5 +1,8 @@
 import base64
 import json
+import typing
+from collections.abc import Sequence
+from typing import Any, Callable, Optional, Union
 
 import pytest
 
@@ -19,6 +22,7 @@ from langchain_core.messages.utils import (
     merge_message_runs,
     trim_messages,
 )
+from langchain_core.tools import BaseTool
 
 
 @pytest.mark.parametrize("msg_cls", [HumanMessage, AIMessage, SystemMessage])
@@ -431,7 +435,15 @@ def dummy_token_counter(messages: list[BaseMessage]) -> int:
 
 
 class FakeTokenCountingModel(FakeChatModel):
-    def get_num_tokens_from_messages(self, messages: list[BaseMessage]) -> int:
+    def get_num_tokens_from_messages(
+        self,
+        messages: list[BaseMessage],
+        tools: Optional[
+            Sequence[
+                Union[typing.Dict[str, Any], type, Callable, BaseTool]  # noqa: UP006
+            ]
+        ] = None,
+    ) -> int:
         return dummy_token_counter(messages)