Bank support
Small but complete example of using PydanticAI to build a support agent for a bank.
Demonstrates:
Running the Example
With dependencies installed and environment variables set, run:
python -m pydantic_ai_examples.bank_support
uv run -m pydantic_ai_examples.bank_support
(or PYDANTIC_AI_MODEL=gemini-1.5-flash ...)
Example Code
bank_support.py
from dataclasses import dataclass
from pydantic import BaseModel, Field
from pydantic_ai import Agent, RunContext
class DatabaseConn:
"""This is a fake database for example purposes.
In reality, you'd be connecting to an external database
(e.g. PostgreSQL) to get information about customers.
"""
@classmethod
async def customer_name(cls, *, id: int) -> str | None:
if id == 123:
return 'John'
@classmethod
async def customer_balance(cls, *, id: int, include_pending: bool) -> float:
if id == 123:
return 123.45
else:
raise ValueError('Customer not found')
@dataclass
class SupportDependencies:
customer_id: int
db: DatabaseConn
class SupportResult(BaseModel):
support_advice: str = Field(description='Advice returned to the customer')
block_card: bool = Field(description='Whether to block their')
risk: int = Field(description='Risk level of query', ge=0, le=10)
support_agent = Agent(
'openai:gpt-4o',
deps_type=SupportDependencies,
result_type=SupportResult,
system_prompt=(
'You are a support agent in our bank, give the '
'customer support and judge the risk level of their query. '
"Reply using the customer's name."
),
)
@support_agent.system_prompt
async def add_customer_name(ctx: RunContext[SupportDependencies]) -> str:
customer_name = await ctx.deps.db.customer_name(id=ctx.deps.customer_id)
return f"The customer's name is {customer_name!r}"
@support_agent.tool
async def customer_balance(
ctx: RunContext[SupportDependencies], include_pending: bool
) -> str:
"""Returns the customer's current account balance."""
balance = await ctx.deps.db.customer_balance(
id=ctx.deps.customer_id,
include_pending=include_pending,
)
return f'${balance:.2f}'
deps = SupportDependencies(customer_id=123, db=DatabaseConn())
result = support_agent.run_sync('What is my balance?', deps=deps)
print(result.data)
"""
support_advice='Hello John, your current account balance, including pending transactions, is $123.45.' block_card=False risk=1
"""
result = support_agent.run_sync('I just lost my card!', deps=deps)
print(result.data)
"""
support_advice="I'm sorry to hear that, John. We are temporarily blocking your card to prevent unauthorized transactions." block_card=True risk=8
"""