tool_hook_in_toolkit.py
"""Show how to use a tool execution hook, to run logic before and after a tool is called."""
import json
from typing import Any, Callable, Dict
from agno.agent import Agent
from agno.tools import Toolkit
from agno.utils.log import logger
# ---------------------------------------------------------------------------
# Create Agent
# ---------------------------------------------------------------------------
class CustomerDBTools(Toolkit):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.register(self.retrieve_customer_profile)
self.register(self.delete_customer_profile)
def retrieve_customer_profile(self, customer_id: str):
"""
Retrieves a customer profile from the database.
Args:
customer_id: The ID of the customer to retrieve.
Returns:
A string containing the customer profile.
"""
logger.info(f"Looking up customer profile for {customer_id}")
return json.dumps(
{
"customer_id": customer_id,
"name": "John Doe",
"email": "john.doe@example.com",
}
)
def delete_customer_profile(self, customer_id: str):
"""
Deletes a customer profile from the database.
Args:
customer_id: The ID of the customer to delete.
"""
logger.info(f"Deleting customer profile for {customer_id}")
return f"Customer profile for {customer_id}"
def validation_hook(
function_name: str, function_call: Callable, arguments: Dict[str, Any]
):
if function_name == "delete_customer_profile":
cust_id = arguments.get("customer_id")
if cust_id == "123":
raise ValueError("Cannot delete customer profile for ID 123")
if function_name == "retrieve_customer_profile":
cust_id = arguments.get("customer_id")
if cust_id == "123":
raise ValueError("Cannot retrieve customer profile for ID 123")
result = function_call(**arguments)
logger.info(
f"Validation hook: {function_name} with arguments {arguments} returned {result}"
)
return result
agent = Agent(tools=[CustomerDBTools()], tool_hooks=[validation_hook])
# This should work
# ---------------------------------------------------------------------------
# Run Agent
# ---------------------------------------------------------------------------
if __name__ == "__main__":
agent.print_response("I am customer 456, please retrieve my profile.")
# This should fail
agent.print_response("I am customer 123, please delete my profile.")
# ---------------------------------------------------------------------------
# Async Variant
# ---------------------------------------------------------------------------
"""Show how to use a tool execution hook with async functions, to run logic before and after a tool is called."""
import asyncio
import json
from inspect import iscoroutinefunction
from typing import Any, Callable, Dict
from agno.agent import Agent
from agno.tools import Toolkit
from agno.utils.log import logger
class CustomerDBTools(Toolkit):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.register(self.retrieve_customer_profile)
self.register(self.delete_customer_profile)
async def retrieve_customer_profile(self, customer_id: str):
"""
Retrieves a customer profile from the database.
Args:
customer_id: The ID of the customer to retrieve.
Returns:
A string containing the customer profile.
"""
logger.info(f"Looking up customer profile for {customer_id}")
return json.dumps(
{
"customer_id": customer_id,
"name": "John Doe",
"email": "john.doe@example.com",
}
)
def delete_customer_profile(self, customer_id: str):
"""
Deletes a customer profile from the database.
Args:
customer_id: The ID of the customer to delete.
"""
logger.info(f"Deleting customer profile for {customer_id}")
return f"Customer profile for {customer_id}"
async def validation_hook(
function_name: str, function_call: Callable, arguments: Dict[str, Any]
):
if function_name == "delete_customer_profile":
cust_id = arguments.get("customer_id")
if cust_id == "123":
raise ValueError("Cannot delete customer profile for ID 123")
if function_name == "retrieve_customer_profile":
cust_id = arguments.get("customer_id")
if cust_id == "123":
raise ValueError("Cannot retrieve customer profile for ID 123")
if iscoroutinefunction(function_call):
result = await function_call(**arguments)
else:
result = function_call(**arguments)
logger.info(
f"Validation hook: {function_name} with arguments {arguments} returned {result}"
)
return result
agent = Agent(tools=[CustomerDBTools()], tool_hooks=[validation_hook])
asyncio.run(agent.aprint_response("I am customer 456, please retrieve my profile."))
asyncio.run(agent.aprint_response("I am customer 456, please delete my profile."))
Run the Example
1
Set up your virtual environment
uv venv --python 3.12
source .venv/bin/activate
uv venv --python 3.12
.venv\Scripts\activate
2
Install dependencies
uv pip install -U agno openai
3
Export your OpenAI API key
export OPENAI_API_KEY="your_openai_api_key_here"
$Env:OPENAI_API_KEY="your_openai_api_key_here"
4
Run the example
Save the code above as
tool_hook_in_toolkit.py, then run:python tool_hook_in_toolkit.py