import type { StacksModelDefinition, StacksModelStatic } from './define-model';
/**
 * A model definition with `extension` folded into it.
 *
 * Exported separately from {@link extendModel} so the merge can be asserted
 * without booting a model.
 */
export declare function mergeModelDefinition(base: StacksModelDefinition, extension: ModelExtension): StacksModelDefinition;
/**
 * Define a model that is the framework's, plus what this app adds.
 *
 * `base` is the framework model itself — import it, do not name it — so the
 * app keeps inheriting fields, traits and relations added upstream.
 */
export declare function extendModel(base: unknown, extension: ModelExtension): StacksModelStatic<StacksModelDefinition>;
/** What an extension may say. Everything is optional; anything absent is inherited. */
export type ModelExtension = Partial<StacksModelDefinition>;