Fraud Alert Verification
Instantly reach cardholders when suspicious activity is detected, confirm whether transactions are legitimate, and lock or unlock accounts — all in real time.
Why this matters
PCI-compliant, fully auditable voice automation for loans, collections, onboarding, and fraud prevention. This example shows you how to automate fraud alert verification calls end-to-end with Guava's SDK — no telephony plumbing, no prompt engineering, just Python.
Installation
Install from Guava's private PyPI index. A public package is coming soon — the install command will simplify to pip install guava.
# Step 1: Install Guava
pip install gridspace-guava --extra-index-url https://guava-pypi.gridspace.com
# Public PyPI package coming soon — the install command will simplify to:
# pip install guava
# Step 2: Set your credentials
export GUAVA_API_KEY="..."
export GUAVA_AGENT_NUMBER="..."How it's built
Every Guava agent is a Python class. Walk through the key sections below, then grab the complete file at the end.
Imports
Import the Guava SDK and any helpers you need. guava.CallController is the base class for every voice agent.
# Install: pip install gridspace-guava --extra-index-url https://guava-pypi.gridspace.com
import guava
import osAgent setup
set_persona() defines how the agent presents itself. set_task() gives it its mission in plain English. The checklist drives the conversation — Guava works through it top-to-bottom, collecting Field values and speaking Say items as it goes.
class FraudVerificationBot(guava.CallController):
def __init__(self, cardholder: str, last_four: str, flagged_transactions: list[dict]):
super().__init__()
self.cardholder = cardholder
self.last_four = last_four
self.flagged = flagged_transactions
self.set_persona(
organization_name="First National Bank Fraud Prevention",
agent_name="Morgan",
)
self.set_task(
objective=f"Verify flagged transactions on card ending {last_four} with {cardholder}",
checklist=[
f"Greet {cardholder} and explain this is a fraud verification call — do NOT ask for full card number.",
guava.Field(
key="verified_identity",
field_type="bool",
description="Verify identity with last 4 of SSN and ZIP code",
),
*[
guava.Field(
key=f"txn_{i}_legitimate",
field_type="bool",
description=f"Did you authorize: {t['merchant']} for ${t['amount']} on {t['date']}?",
)
for i, t in enumerate(flagged_transactions)
],
guava.Field(
key="freeze_card",
field_type="bool",
description="Does the cardholder want to freeze their card?",
),
"Confirm resolution and provide case reference number.",
],
on_complete=self.resolve_fraud,
)
def resolve_fraud(self, fields):
fraudulent = [i for i, t in enumerate(self.flagged) if not fields.get(f"txn_{i}_legitimate")]
if fraudulent or fields.get("freeze_card"):
print(f"Freezing card for {self.cardholder}, flagging {len(fraudulent)} transactions")
guava.dial(
controller=FraudVerificationBot,
controller_args={
"cardholder": "Patricia Lane",
"last_four": "4821",
"flagged_transactions": [
{"merchant": "Amazon Marketplace", "amount": "847.99", "date": "today at 2:14pm"},
{"merchant": "Steam Games", "amount": "129.00", "date": "today at 2:17pm"},
],
},
to=os.environ["CARDHOLDER_PHONE"],
agent_number=os.environ["GUAVA_AGENT_NUMBER"],
api_key=os.environ["GUAVA_API_KEY"],
)Platform performance
<1s
Response time
99.99%
Uptime SLA
13+
Industries served
Full example
The complete file — copy it, save it as example.py, and run it.
# Install: pip install gridspace-guava --extra-index-url https://guava-pypi.gridspace.com
import guava
import os
class FraudVerificationBot(guava.CallController):
def __init__(self, cardholder: str, last_four: str, flagged_transactions: list[dict]):
super().__init__()
self.cardholder = cardholder
self.last_four = last_four
self.flagged = flagged_transactions
self.set_persona(
organization_name="First National Bank Fraud Prevention",
agent_name="Morgan",
)
self.set_task(
objective=f"Verify flagged transactions on card ending {last_four} with {cardholder}",
checklist=[
f"Greet {cardholder} and explain this is a fraud verification call — do NOT ask for full card number.",
guava.Field(
key="verified_identity",
field_type="bool",
description="Verify identity with last 4 of SSN and ZIP code",
),
*[
guava.Field(
key=f"txn_{i}_legitimate",
field_type="bool",
description=f"Did you authorize: {t['merchant']} for ${t['amount']} on {t['date']}?",
)
for i, t in enumerate(flagged_transactions)
],
guava.Field(
key="freeze_card",
field_type="bool",
description="Does the cardholder want to freeze their card?",
),
"Confirm resolution and provide case reference number.",
],
on_complete=self.resolve_fraud,
)
def resolve_fraud(self, fields):
fraudulent = [i for i, t in enumerate(self.flagged) if not fields.get(f"txn_{i}_legitimate")]
if fraudulent or fields.get("freeze_card"):
print(f"Freezing card for {self.cardholder}, flagging {len(fraudulent)} transactions")
guava.dial(
controller=FraudVerificationBot,
controller_args={
"cardholder": "Patricia Lane",
"last_four": "4821",
"flagged_transactions": [
{"merchant": "Amazon Marketplace", "amount": "847.99", "date": "today at 2:14pm"},
{"merchant": "Steam Games", "amount": "129.00", "date": "today at 2:17pm"},
],
},
to=os.environ["CARDHOLDER_PHONE"],
agent_number=os.environ["GUAVA_AGENT_NUMBER"],
api_key=os.environ["GUAVA_API_KEY"],
)Run it
Start the agent. It will connect to Guava's infrastructure and begin accepting calls on your assigned number.
python example.py