/**
 * @license
 * Copyright 2026 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
/** Describes the optional peer dependency a feature is asking for. */
export interface OptionalPeer {
    /** The npm package name, e.g. `@google-cloud/storage`. */
    packageName: string;
    /** The ADK feature that needs it, used in the error message. */
    feature: string;
}
/**
 * Loads an optional peer dependency, translating "not installed" into an
 * actionable error.
 *
 * The dynamic `import()` is passed in as a thunk rather than being built from
 * `packageName`, so that the specifier stays a literal in the calling module
 * and remains visible to bundlers and to test doubles installed with
 * `vi.mock()`.
 *
 * ```ts
 * const {Storage} = await loadOptionalPeer(
 *   {packageName: '@google-cloud/storage', feature: 'GcsArtifactService'},
 *   () => import('@google-cloud/storage'),
 * );
 * ```
 *
 * @param peer The package being loaded and the feature that needs it.
 * @param load Thunk performing the dynamic `import()`.
 * @return The imported module namespace.
 * @throws If the package is not installed, an error naming the feature and
 *   the `npm install` command that fixes it. Any other load failure is
 *   rethrown unchanged.
 */
export declare function loadOptionalPeer<T>(peer: OptionalPeer, load: () => Promise<T>): Promise<T>;