PydanticAI Advanced Error Handling and Testing (Python)

PydanticAI Advanced Error Handling and Testing (Python)

Last verified: 2025-11

Validation-First Design

• Model outputs with Pydantic; retry generation on validation errors

from pydantic import BaseModel, ValidationError

class Answer(BaseModel):
    bullets: list[str]

def parse_or_retry(raw: str) -> Answer:
    try:
        return Answer.model_validate_json(raw)
    except ValidationError:
        # re-prompt with error hints or stricter schema
        raise

Testing Strategy

• Unit: model schemas, validators
• Integration: agent runs with mocked model
• Snapshot: golden outputs for prompts