Identity & Ownership

Person vs Group

The Identity kernel contains two core entities:

Every component that stores data references either a Person or Group—never both, and never neither. This is the owner_id pattern.

The owner_id Pattern

Every entity carries an owner_id: a UUID pointing to either a Person or Group in the Identity kernel. This single field enables:

• Multi-tenancy — Data is scoped by owner; no leakage between users
• Sharing — Same entity structure works for private (Person) and shared (Group) data
• Querying — Every repository can filter by owner_id

@dataclass
class Task:
    id: UUID
    owner_id: UUID      # Person or Group
    title: str
    status: TaskStatus
    container_id: UUID  # Which list/project
    ...

A task owned by a Person is private. The same task structure owned by a Group becomes shared—visible to all group members. The Todos component doesn't distinguish; it just filters by owner_id.

Multi-Tenancy Without Complexity

Components don't know whether they're serving a Person or Group. They just:

1. Receive owner_id in API requests
2. Store it on every entity they create
3. Filter by it on every query

Authorization (can this user access this owner_id?) is handled by Policy, not by individual components.