> ## Documentation Index > Fetch the complete documentation index at: https://phidatainc.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Tool Hooks in Toolkit Nested > Nest validation and logging hooks around toolkit tools to block customer ID 123 and strip the name field from results, in sync and async variants. Show how to use multiple tool execution hooks, to run logic before and after a tool is called. ```python tool_hooks_in_toolkit_nested.py theme={null} """Show how to use multiple tool execution hooks, 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 # --------------------------------------------------------------------------- # 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(name: str, func: Callable, arguments: Dict[str, Any]): if name == "retrieve_customer_profile": cust_id = arguments.get("customer_id") if cust_id == "123": raise ValueError("Cannot retrieve customer profile for ID 123") if name == "delete_customer_profile": cust_id = arguments.get("customer_id") if cust_id == "123": raise ValueError("Cannot delete customer profile for ID 123") logger.info("Before Validation Hook") result = func(**arguments) logger.info("After Validation Hook") # Remove name from result to sanitize the output result = json.loads(result) result.pop("name") return json.dumps(result) def logger_hook(name: str, func: Callable, arguments: Dict[str, Any]): logger.info("Before Logger Hook") result = func(**arguments) logger.info("After Logger Hook") return result sync_agent = Agent( tools=[CustomerDBTools()], # Hooks are executed in order of the list tool_hooks=[validation_hook, logger_hook], ) # --------------------------------------------------------------------------- # Async Variant # --------------------------------------------------------------------------- class CustomerDBToolsAsync(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_async(name: str, func: Callable, arguments: Dict[str, Any]): if name == "retrieve_customer_profile": cust_id = arguments.get("customer_id") if cust_id == "123": raise ValueError("Cannot retrieve customer profile for ID 123") if name == "delete_customer_profile": cust_id = arguments.get("customer_id") if cust_id == "123": raise ValueError("Cannot delete customer profile for ID 123") logger.info("Before Validation Hook") if iscoroutinefunction(func): result = await func(**arguments) else: result = func(**arguments) logger.info("After Validation Hook") # Remove name from result to sanitize the output if name == "retrieve_customer_profile": result = json.loads(result) result.pop("name") return json.dumps(result) return result async def logger_hook_async(name: str, func: Callable, arguments: Dict[str, Any]): logger.info("Before Logger Hook") if iscoroutinefunction(func): result = await func(**arguments) else: result = func(**arguments) logger.info("After Logger Hook") return result async_agent = Agent( tools=[CustomerDBToolsAsync()], # Hooks are executed in order of the list tool_hooks=[validation_hook_async, logger_hook_async], ) # --------------------------------------------------------------------------- # Run Agent # --------------------------------------------------------------------------- if __name__ == "__main__": sync_agent.print_response("I am customer 456, please retrieve my profile.") asyncio.run( async_agent.aprint_response( "I am customer 456, please retrieve my profile.", stream=True ) ) asyncio.run( async_agent.aprint_response( "I am customer 456, please delete my profile.", stream=True ) ) ``` ## Run the Example ```bash theme={null} uv pip install -U agno openai ``` ```bash Mac/Linux theme={null} export OPENAI_API_KEY="your_openai_api_key_here" ``` ```bash Windows theme={null} $Env:OPENAI_API_KEY="your_openai_api_key_here" ``` Save the code above as `tool_hooks_in_toolkit_nested.py`, then run: ```bash theme={null} python tool_hooks_in_toolkit_nested.py ``` Full source: [cookbook/91\_tools/tool\_hooks/tool\_hooks\_in\_toolkit\_nested.py](https://github.com/agno-agi/agno/blob/main/cookbook/91_tools/tool_hooks/tool_hooks_in_toolkit_nested.py)