# ADR 0006: Use Pydantic for Domain Models

## Status

Accepted

## Context

The application manages structured and versioned entities such as meetings,
recordings, transcripts, participants and AI-generated artifacts.

These entities must be:

- type-safe
- validated at runtime
- serializable to JSON
- loadable from persisted JSON
- independent of the storage implementation

Python dataclasses provide a lightweight representation but do not provide
the required validation and serialization behavior without additional code.

## Decision

The project will use Pydantic models for its domain model.

Domain models shall inherit from a shared project base model.

Storage-specific behavior, database access and processing logic must not be
implemented inside the domain models.

## Consequences

- Invalid data can be rejected at module boundaries.
- Domain objects can be serialized to and restored from JSON.
- JSON schemas can be generated for interfaces and documentation.
- Pydantic becomes a core project dependency.
- Domain models remain independent of the eventual storage backend.