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Disabling parallel tool calling (OpenAI only)​

OpenAI tool calling performs tool calling in parallel by default. That means that if we ask a question like "What is the weather in Tokyo, New York, and Chicago?" and we have a tool for getting the weather, it will call the tool 3 times in parallel. We can force it to call only a single tool once by using the parallel_tool_call parameter.

First let's set up our tools and model:

from import tool

def add(a: int, b: int) -> int:
"""Adds a and b."""
return a + b

def multiply(a: int, b: int) -> int:
"""Multiplies a and b."""
return a * b

tools = [add, multiply]
API Reference:tool
import os
from getpass import getpass

from langchain_openai import ChatOpenAI

os.environ["OPENAI_API_KEY"] = getpass()

llm = ChatOpenAI(model="gpt-3.5-turbo-0125", temperature=0)
API Reference:ChatOpenAI

Now let's show a quick example of how disabling parallel tool calls work:

llm_with_tools = llm.bind_tools(tools, parallel_tool_calls=False)
llm_with_tools.invoke("Please call the first tool two times").tool_calls
[{'name': 'add',
'args': {'a': 2, 'b': 2},
'id': 'call_Hh4JOTCDM85Sm9Pr84VKrWu5'}]

As we can see, even though we explicitly told the model to call a tool twice, by disabling parallel tool calls the model was constrained to only calling one.

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