AI Message with No Content but Tool Calls Gets Removed

[AustinJiangH]

An AIMessage with no text content but only tool calls will be trimmed out.

AIMessage(
        content="",
        additional_kwargs={},
        response_metadata={
            "id": "msg_vrtx_23232323232323",
            "model": "claude-3-5-sonnet-v2-20241022",
            "stop_reason": "tool_use",
            "stop_sequence": None,
            "usage": {
                "cache_creation_input_tokens": 0,
                "cache_read_input_tokens": 0,
                "input_tokens": 111,
                "output_tokens": 111,
            },
        },
        name="tool_call_node",
        id="run-xxxxxxx",
        tool_calls=[
            {
                "name": "mocked_tool",
                "args": {
                    "arg_1": "value_1",
                    "arg_2": ["value2"],
                },
                "id": "toolu_vrtx_23232323233232323",
                "type": "tool_call",
            }
        ],
        usage_metadata={
            "input_tokens": 111,
            "output_tokens": 111,
            "total_tokens": 222,
            "cache_creation_input_tokens": 0,
            "cache_read_input_tokens": 0,
        },
    )

The error is in this function.

langchain-google/libs/vertexai/langchain_google_vertexai/_anthropic_utils.py

Lines 116 to 131 in 7027058

	def _format_message_anthropic(
	message: Union[HumanMessage, AIMessage, SystemMessage], project: Optional[str]
	):
	"""Format a message for Anthropic API.
	Args:
	message: The message to format. Can be HumanMessage, AIMessage, or SystemMessage.
	Returns:
	A dictionary with the formatted message, or None if the message is empty.
	""" # noqa: E501
	content: List[Dict[str, Any]] = []
	if isinstance(message.content, str):
	if not message.content.strip():
	return None