mixed_hooks.py
"""
Mixed Hooks and Guardrails
=============================
Example demonstrating how to combine plain hooks with guardrails in pre_hooks.
Both run in order: the logging hook fires, then the PII guardrail checks
for sensitive data. If PII is detected the run is rejected with RunStatus.error.
"""
from agno.agent import Agent
from agno.guardrails import PIIDetectionGuardrail
from agno.models.openai import OpenAIResponses
from agno.run import RunStatus
from agno.run.agent import RunInput
# ---------------------------------------------------------------------------
# Plain hook (non-guardrail)
# ---------------------------------------------------------------------------
def log_request(run_input: RunInput) -> None:
"""Pre-hook that logs every incoming request."""
print(f" [log_request] Input: {run_input.input_content[:60]}")
# ---------------------------------------------------------------------------
# Create Agent
# ---------------------------------------------------------------------------
def main():
print("Mixed Hooks and Guardrails Demo")
print("=" * 50)
agent = Agent(
name="Privacy-Protected Agent",
model=OpenAIResponses(id="gpt-4o-mini"),
pre_hooks=[log_request, PIIDetectionGuardrail()],
instructions="You are a helpful assistant that protects user privacy.",
)
# Test 1: Clean input — hook runs, guardrail passes, agent responds
print("\n[TEST 1] Clean input (no PII)")
print("-" * 40)
response = agent.run(input="What is the weather today?")
if response.status == RunStatus.error:
print(f" [ERROR] Unexpected block: {response.content}")
else:
print(f" [OK] Agent responded: {response.content[:80]}")
# Test 2: PII input — guardrail blocks before agent sees the data
print("\n[TEST 2] Input with SSN")
print("-" * 40)
response = agent.run(input="My SSN is 123-45-6789, can you help?")
if response.status == RunStatus.error:
print(f" [BLOCKED] Guardrail rejected: {response.content}")
else:
print(" [WARNING] Should have been blocked!")
# Test 3: PII input with credit card
print("\n[TEST 3] Input with credit card")
print("-" * 40)
response = agent.run(input="My card is 4532 1234 5678 9012, charge it.")
if response.status == RunStatus.error:
print(f" [BLOCKED] Guardrail rejected: {response.content}")
else:
print(" [WARNING] Should have been blocked!")
print("\n" + "=" * 50)
print("Mixed Hooks and Guardrails Demo Complete")
# ---------------------------------------------------------------------------
# Run Agent
# ---------------------------------------------------------------------------
if __name__ == "__main__":
main()
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
mixed_hooks.py, then run:python mixed_hooks.py