An error occurred: BaseTool.__call__() missing 1 required positional argument: 'tool_input'

[0xrushi]

The tool is expecting an argument, but I haven't provided one. Why is that?

from langchain_core.prompts import ChatPromptTemplate
from langchain_ollama.llms import OllamaLLM
from langchain_ollama.chat_models import ChatOllama
from langchain_core.messages import AIMessage, HumanMessage, SystemMessage
from langchain_core.tools import tool
from langgraph.prebuilt import ToolNode
from typing import Literal
from langgraph.graph import StateGraph, MessagesState, START, END


@tool
def get_weather(location: str):
    """Call to get the current weather."""
    if location.lower() in ["sf", "san francisco"]:
        return "It's 60 degrees and foggy."
    else:
        return "It's 90 degrees and sunny."


@tool
def get_coolest_cities():
    """Get a list of coolest cities. No input required."""
    return "nyc, sf"


def create_agent():
    tools = [get_weather, get_coolest_cities]
    tool_node = ToolNode(tools)
    
    system_prompt = """You are a helpful assistant. Use tools when appropriate to get accurate information."""
    
    prompt = ChatPromptTemplate.from_messages([
        ("system", system_prompt),
        ("human", "{input}"),
    ])
    
    model = ChatOllama(model="qwen2.5:14b")
    model_with_tools = model.bind_tools(tools).bind(prompt=prompt)

    def should_continue(state: MessagesState):
        messages = state["messages"]
        last_message = messages[-1]
        if isinstance(last_message, AIMessage) and hasattr(last_message, 'tool_calls') and last_message.tool_calls:
            return "tools"
        return END

    def call_model(state: MessagesState):
        messages = state["messages"]
        # If there's no system message at the start, add it
        if not messages or not isinstance(messages[0], SystemMessage):
            messages = [SystemMessage(content=system_prompt)] + messages
        response = model_with_tools.invoke(messages)
        return {"messages": [response]}

    workflow = StateGraph(MessagesState)
    workflow.add_node("agent", call_model)
    workflow.add_node("tools", tool_node)

    workflow.add_edge(START, "agent")
    workflow.add_conditional_edges("agent", should_continue, ["tools", END])
    workflow.add_edge("tools", "agent")

    return workflow.compile()


def main():
    app = create_agent()
    messages = [SystemMessage(content="""You are a helpful assistant. Use tools when appropriate to get accurate information.""")]
    
    print("Welcome! You can chat with me about the weather or cool cities. Type 'quit' to exit.")
    
    while True:
        user_input = input("\nYou: ").strip()
        
        if user_input.lower() == 'quit':
            break
            
        messages.append(HumanMessage(content=user_input))
        
        try:
            for chunk in app.stream({"messages": messages}, stream_mode="values"):
                response = chunk["messages"][-1]
                
                if isinstance(response, AIMessage):
                    if response.content:
                        print("\nAssistant:", response.content)
                    
                    if hasattr(response, 'tool_calls') and response.tool_calls:
                        for tool_call in response.tool_calls:
                            print(f"\nUsing tool: {tool_call['name']}")
                            print(f"Arguments: {tool_call['args']}")
                            if 'location' in tool_call['args']:
                                result = get_weather(tool_call['args']['location'])
                                print(f"Weather result: {result}")
                            elif tool_call['name'] == 'get_coolest_cities':
                                result = get_coolest_cities()
                                print(f"Cool cities: {result}")
                
                messages.extend(chunk["messages"])
                
        except Exception as e:
            print(f"\nAn error occurred: {str(e)}")
            continue


if __name__ == "__main__":
    main()

[dosubot[bot]]

I found similar discussions related to the error you're encountering:

1. TypeError: BaseTool.call() missing 1 required positional argument: 'tool_input' ^[1].
2. Tool Input exception for query ^[2].

Additionally, there was a related issue that has been closed: Langchain Tools: TypeError: BaseTool.invoke() takes from 2 to 3 positional arguments but 4 were given. The suggested solution for a similar problem was to ensure that the invoke method is called with the correct input format, like this:

shell_tool.invoke(input={"command": 'python sum.py', "script_args": None, "inputs": '5\n'})

In your case, it seems like the error might be due to how the invoke method is being called. Ensure that the input to invoke is correctly formatted as a dictionary with the expected keys and values. You might need to adjust the way you are passing the messages to the invoke method to match the expected input structure.

To continue talking to Dosu, mention @dosu.

[0xrushi]

That did the trick—well done, Mr bot!