AI Agent Custom Tool Development 2026

Want to add a weather-checking feature to your Agent? No need to understand Agent frameworks. One Python function + one decorator, and the Agent automatically learns to use it.

💡 What You Will Learn

Want to add a weather-checking feature to your Agent? No need to understand Agent frameworks. One Python function + one decorator, and the Agent automatically learns to use it.

def get_stock_price(symbol: str) -> float:
    """"""
    import requests
    data = requests.get(f"https://api.example.com/stock/{symbol}").json()
    return data["price"]

from agent_sdk import tool

@tool
def get_stock_price(symbol: str) -> float:
    \"\"\"symbolAAPLGOOGL\"\"\"

agent.register_tool(get_stock_price)

Summary

import requests
from agent_sdk import tool, ToolSet

@tool
def get_exchange_rate(from_currency: str, to_currency: str = "CNY") -> float:
    """
    from_currency: USDEURJPY
    to_currency: CNY

    """
    url = f"https://api.exchangerate-api.com/v4/latest/{from_currency}"
    data = requests.get(url).json()
    return data["rates"][to_currency]

# 
agent.register_tool(get_exchange_rate)