app.py

from langchain_experimental.llms.ollama_functions import OllamaFunctions
from langchain_core.messages import HumanMessage, ToolMessage

model = OllamaFunctions(
    model="llama3",
    format="json"
    )


@tool
def add(a: int, b: int) -> int:
    """Adds a and b. Args: a: first int b: second int """
    return a + b


@tool
def multiply(a: int, b: int) -> int:
    """Multiplies a and b. Args: a: first int b: second int"""
    return a * b


tools = [add, multiply]
llm_with_tools = model.bind_tools(tools)

messages = [HumanMessage(query)]
ai_msg = llm_with_tools.invoke(messages)
messages.append(ai_msg)

for tool_call in ai_msg.tool_calls:
    selected_tool = {"add": add, "multiply": multiply}[tool_call["name"].lower()]
    tool_output = selected_tool.invoke(tool_call["args"])
    messages.append(ToolMessage(tool_output, tool_call_id=tool_call["id"]))

messages