Adding other tools

Now that you've built a capable agent, we hope you're excited about all it can do. The core of expanding agent capabilities is the tools available, and we have good news: LlamaHub from LlamaIndex has hundreds of integrations, including dozens of existing agent tools that you can use right away. We'll show you how to use one of the existing tools, and also how to build and contribute your own.

Using an existing tool from LlamaHub

For our example, we're going to use the Yahoo Finance tool from LlamaHub. It provides a set of six agent tools that look up a variety of information about stock ticker symbols.

First we need to install the tool:

pip install llama-index-tools-yahoo-finance

Then we can set up our dependencies. This is exactly the same as our previous examples, except for the final import:

from dotenv import load_dotenv

load_dotenv()
from llama_index.core.agent import ReActAgent
from llama_index.llms.openai import OpenAI
from llama_index.core.tools import FunctionTool
from llama_index.core import Settings
from llama_index.tools.yahoo_finance import YahooFinanceToolSpec

To show how custom tools and LlamaHub tools can work together, we'll include the code from our previous examples the defines a "multiple" tool. We'll also take this opportunity to set up the LLM:

# settings
Settings.llm = OpenAI(model="gpt-4o", temperature=0)


# function tools
def multiply(a: float, b: float) -> float:
    """Multiply two numbers and returns the product"""
    return a * b


multiply_tool = FunctionTool.from_defaults(fn=multiply)


def add(a: float, b: float) -> float:
    """Add two numbers and returns the sum"""
    return a + b


add_tool = FunctionTool.from_defaults(fn=add)

Now we'll do the new step, which is to fetch the array of tools:

finance_tools = YahooFinanceToolSpec().to_tool_list()

This is just a regular array, so we can use Python's extend method to add our own tools to the mix:

finance_tools.extend([multiply_tool, add_tool])

Then we set up the agent as usual, and ask a question:

agent = ReActAgent.from_tools(finance_tools, verbose=True)

response = agent.chat("What is the current price of NVDA?")

print(response)

The response is very wordy, so we've truncated it:

Thought: The current language of the user is English. I need to use a tool to help me answer the question.
Action: stock_basic_info
Action Input: {'ticker': 'NVDA'}
Observation: Info:
{'address1': '2788 San Tomas Expressway'
...
'currentPrice': 135.58
...}
Thought: I have obtained the current price of NVDA from the stock basic info.
Answer: The current price of NVDA (NVIDIA Corporation) is $135.58.
The current price of NVDA (NVIDIA Corporation) is $135.58.

Perfect! As you can see, using existing tools is a snap.

As always, you can check the repo to see this code all in one place.

Building and contributing your own tools

We love open source contributions of new tools! You can see an example of what the code of the Yahoo finance tool looks like: * A class that extends BaseToolSpec * A set of arbitrary Python functions * A spec_functions list that maps the functions to the tool's API

Once you've got a tool working, follow our contributing guide for instructions on correctly setting metadata and submitting a pull request.

Congratulations! You've completed our guide to building agents with LlamaIndex. We can't wait to see what use-cases you build!