The optional wrapLoader host hook and development_updates: 1 build metadata let compatible hosts replace development App surfaces without reloading the Shell. Existing hosts can omit the hook.

Use Core 0.8.34, CLI 0.2.0-alpha.13 and sandbox-manager 0.1.0-alpha.24 or compatible later versions, then rebuild the development App with React SDK 0.8.6. Unsaved forms and pending writes defer replacement. Component-local state may reset; this is not React Fast Refresh.