Mixed Hooks and Guardrails

Combine a logging pre-hook with PIIDetectionGuardrail; blocked runs return RunStatus.error instead of raising.

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.

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-5.6-luna"),
        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()

The logging hook runs before the PII check and prints the beginning of the raw input, including the sample SSN or card number. This example blocks matching model input, but it does not redact logs. Remove that raw-input print or log only non-sensitive request metadata when using this pattern with real data. A generic RunStatus.error can also indicate a provider failure; it is not proof of PII detection.

Run the Example

Set up your virtual environment

uv venv --python 3.12
source .venv/bin/activate

Install dependencies

uv pip install -U agno openai

Export your OpenAI API key

export OPENAI_API_KEY="your_openai_api_key_here"

Run the example

Save the code above as mixed_hooks.py, then run:

python mixed_hooks.py

Full source: cookbook/02_agents/08_guardrails/mixed_hooks.py