Pydantic AI: Build Type-Safe LLM Agents in Python
Pydantic AI is a Python framework for building LLM agents that return validated, structured outputs using Pydantic models. Instead of parsing raw strings from LLMs, you get type-safe objects with automatic validation.
If you’ve used FastAPI or Pydantic before, then you’ll recognize the familiar pattern of defining schemas with type hints and letting the framework handle the type validation for you.
By the end of this tutorial, you’ll understand that:
- Pydantic AI uses
BaseModelclasses to define structured outputs that guarantee type safety and automatic validation. - The
@agent.tooldecorator registers Python functions that LLMs can invoke based on user queries and docstrings. - Dependency injection with
deps_typeprovides type-safe runtime context like database connections without using global state. - Validation retries