/**
 * ~/.clustly/credentials — the builder key at rest (design: docs/designs/clustly-cli.md §4;
 * build-plan 3.3). Owner-only modes; the plaintext key lives ONLY here and in the server's
 * hashed form. Reads are forgiving (missing/corrupt → signed out); writes are NOT best-effort
 * — failing to persist a just-minted key is a failed login and must say so.
 */
export interface Credentials {
    apiKey: string;
    keyPrefix: string;
    savedAt: string;
}
export declare const BUILDER_KEY_PATTERN: RegExp;
/** Display/lookup prefix length — the server-side agent_api_keys/builder_keys convention. */
export declare const KEY_DISPLAY_PREFIX_LEN = 8;
export declare function readCredentials(home: string, warn?: (line: string) => void): Credentials | undefined;
export declare function writeCredentials(home: string, apiKey: string, keyPrefix: string): Credentials;
/** Returns true when something was actually removed. */
export declare function clearCredentials(home: string): boolean;