AttributeError when tool invoked with 2 arguments

[prajwal-svl]

I am trying to create a tool which reviews the generated ad copy, accepting the ad and the review request from the user. Calling the invoke I get the following error:

AttributeError:` 'str' object has no attribute 'items'

 File "langgraph_agent.py", line 86, in review_ad_copy
    review_status = tool.invoke(ad_copy.content, review_request.content)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "venv/lib/python3.11/site-packages/langchain_core/tools.py", line 426, in invoke
    tool_input, kwargs = _prep_run_args(input, config, **kwargs)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "venv/lib/python3.11/site-packages/langchain_core/tools.py", line 1467, in _prep_run_args
    config = ensure_config(config)
             ^^^^^^^^^^^^^^^^^^^^^
  File "venv/lib/python3.11/site-packages/langchain_core/runnables/config.py", line 187, in ensure_config
    for k, v in config.items()
                ^^^^^^^^^^^^
AttributeError: 'str' object has no attribute 'items'

Here is the node that invokes the tool:

def review_ad_copy(state: GraphState) -> Dict[str, AnyMessage]:
    """
    Node to review the ad copy and ask for feedback.
    """
    review_request: str = state["messages"][-1]
    ad_copy: str = state["messages"][-2]
    tool = available_functions.get('review_ad_copy', None)
    review_status = tool.invoke(ad_copy.content, review_request.content)

    return {"messages": AIMessage(review_status), "current_node": "review_ad_copy"}

Also this is my tool:

@tool
def review_ad_copy(ad_copy: str, review_request: str):
    """
    Generates a new ad copy based on the provided ad copy and review request
    Example call:

    request_next_campaign_info("My product is great", "Please add more details about the product")
    Args:
        ad_copy (str): The ad copy to be reviewed
        review_request (str): The review request
    Returns:
        str: The generate ad copy
    """

    system_message = """
    You are a seasoned marketer tasked with reviewing and changing an ad copy for a marketing campaign.
    You need to generate an ad copy based on the provided ad copy and review request.
    """

    human_message = f"""
        Please perform the following changes and generate a new ad copy.
        
        Current Ad Copy: {ad_copy}
        
        Review Request: {review_request}
    """

    conversation = [
        SystemMessage(content=system_message),
        HumanMessage(content=human_message),
    ]

    response = chatbot(conversation)

    return response.content

What I am doing wrong here? I don't have this issue when the tool accepts a single parameter.
Just starting off, excuse my ignorance

[hinthornw]

Good q:

review_ad_copy.invoke({"ad_copy": ad_copy.content,  "review_request": review_request.content})

[prajwal-svl]

Thanks.
I changed to:

   tool = available_functions.get('review_ad_copy', None)
    review_status = tool.invoke({"ad_copy": ad_copy.content, "review_request": review_request.content})

Although this runs. I get deprecated warning

LangChainDeprecationWarning: The method `BaseChatModel.__call__` was deprecated in langchain-core 0.1.7 and will be removed in 0.3.0. Use invoke instead.
  warn_deprecated(

[vbarda]

this probably because you need to do response = chatbot.invoke(conversation) instead of response = chatbot(conversation)

[prajwal-svl]

I am calling the invoke function right in the above.

I don't follow could you explain?

[hinthornw]

@vbarda is talking about the chatbot call within your tool. You are now calling the tool correctly, but within that you are calling "chatbot(...)" instead of "chatbot.invoke(...)"