/**
 * Loading a heavy dependency only if the tool that needs it is actually used.
 *
 * Eleven packages were imported at module top level and shipped in nobody's
 * install -- `typescript`, `@babel/parser`, `@typescript-eslint/typescript-estree`,
 * `prettier`, `react` and others were devDependencies or absent entirely. On a
 * developer's machine they resolve out of node_modules and everything looks
 * fine. On a user's machine `npm i -g` installs only `dependencies`, so around
 * twelve advertised MCP tools threw
 *
 *     Cannot find package 'typescript' imported from ...
 *
 * the moment anything touched them. Dead on arrival, with an error that tells
 * the user nothing about what to do.
 *
 * The small dependencies are now declared and simply work. The heavy ones --
 * a TypeScript compiler is 20 MB, and most sessions never run a code-analysis
 * tool -- load on first use through here, so:
 *
 *   - installing the package stays cheap for the people who never need them
 *   - a tool that cannot run says WHICH package is missing and the exact
 *     command that fixes it
 *   - the failure happens when the tool is called, not when it is imported, so
 *     one missing optional package cannot take the whole server down
 *
 * `cache-compression` already did this correctly for lz4/zstd/snappy. This is
 * that pattern, made shared and given a decent error message.
 */
export declare class MissingOptionalDependency extends Error {
    readonly packageName: string;
    readonly toolName: string;
    readonly why: string;
    constructor(packageName: string, toolName: string, why: string);
}
/**
 * Imports an optional package, or explains precisely why it could not.
 *
 * @param packageName what to import, exactly as it would be typed into npm
 * @param toolName    the tool asking, so the message names something the user
 *                    recognises rather than a file path
 * @param why         one line on what the package is for, so the user can
 *                    decide whether they want it at all
 */
export declare function optionalDependency<T = unknown>(packageName: string, toolName: string, why: string): Promise<T>;
/** Whether an optional package is available, without throwing. */
export declare function hasOptionalDependency(packageName: string): Promise<boolean>;
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