# ADR 0005: Prefab Instance and Asset Registry

## Status

Accepted

## Context

Editor prefab placement and content pipeline work (H1/H2) require stable asset identity across sessions. The asset browser previously regenerated UUIDs on every sync, breaking references.

## Decision

- Persist stable `AssetId` (UUID) per `assets/` path in `assets/.index/registry.ron`.
- Introduce `PrefabInstance { asset_id, source_path, overrides_ron }` on placed prefab roots alongside hydration via `PrefabRef`.
- Scene save includes `PrefabInstance` and gameplay marker components from `shared`.

## Consequences

- Prefab paths can be resolved through the registry for dependency tracking.
- Override apply/revert (H2) builds on `overrides_ron` without changing the instance component shape.
- Registry must be version-controlled with the project.