# Event and Registry Model Spec

## Purpose

Define how domain hubs publish structured facts and interaction evidence into Core Hub.

## Event Principles

- Event types are cataloged.
- Payload schemas are versioned.
- Producers identify hub, repo, actor, source system, and correlation identifiers where available.
- Events are append-oriented; derived read models can be rebuilt.
- Event payloads must not contain secrets.

## Registry Principles

- Capability and manifest records are discoverable.
- Domain hubs publish what they provide, what they consume, and how operators or agents can interact with them.
- Registry entries link to source docs and tests when possible.
- Drift between repo files and Core Hub records is detectable.

## Initial Catalog Families

- hub capability manifests
- widget types and widget instances
- interaction event types
- annotation categories
- policy scopes
- API consumers
- outcome correlations
- capability registry entries

## Acceptance Standard

A registry family is ready when it has:

- schema;
- fixture;
- read endpoint;
- write/upsert path if needed;
- validation errors;
- consumer guidance;
- at least one compatibility or integration test.