PydanticAI

PydanticAI treats LLMs as typed functions. It works against ai& through its OpenAI-compatible provider.

Setup

pip install pydantic-ai

from pydantic_ai import Agent
from pydantic_ai.models.openai import OpenAIModel
from pydantic_ai.providers.openai import OpenAIProvider

model = OpenAIModel(
    "openai/gpt-oss-120b",
    provider=OpenAIProvider(
        base_url="https://api.aiand.com/v1",
        api_key="sk-your-api-key",
    ),
)

A typed agent

agent = Agent(model, system_prompt="Be concise.")
result = await agent.run("What is the capital of France?")
print(result.output)

Structured outputs

from pydantic import BaseModel

class Contact(BaseModel):
    name: str
    email: str

agent = Agent(model, output_type=Contact)
result = await agent.run("From: Jane Doe <jane@example.com>")
print(result.output.name, result.output.email)

The schema is shipped to ai& as a strict JSON Schema and the output is parsed back into the Pydantic model.

Tools

@agent.tool_plain
def get_weather(city: str) -> str:
    """Get current weather for a city."""
    return f"Sunny in {city}, 22°C"

result = await agent.run("What's the weather in Tokyo?")
print(result.output)