export type CheckpointOptions = {
    /**
     * - Tool names that require approval (exact match).
     */
    tools?: string[] | undefined;
    /**
     * - Custom predicate — overrides tools list if set.
     */
    shouldAsk?: ((toolName: string, args: any) => boolean) | undefined;
    /**
     * - Async `(question, context) => void` to deliver the question.
     */
    send?: ((question: string, context: any) => any) | undefined;
    /**
     * - Async `(context) => string` that resolves with the user's reply.
     */
    waitForReply?: ((context: any) => any) | undefined;
    /**
     * - Ms to wait before auto-denying. 0 disables.
     */
    timeout?: number | undefined;
};
/**
 * @typedef {object} CheckpointOptions
 * @property {Array<string>} [tools] - Tool names that require approval (exact match).
 * @property {(toolName: string, args: any) => boolean} [shouldAsk] - Custom predicate — overrides tools list if set.
 * @property {(question: string, context: any) => any} [send] - Async `(question, context) => void` to deliver the question.
 * @property {(context: any) => any} [waitForReply] - Async `(context) => string` that resolves with the user's reply.
 * @property {number} [timeout=300000] - Ms to wait before auto-denying. 0 disables.
 */
export class Checkpoint {
    /**
     * @param {CheckpointOptions} [options={}]
     * @when you want an always-prompt human-in-the-loop approval gate on chosen tools — complementary to bareguard's policy-driven pauses
     * @fails auto-denies on timeout (0 disables) and denies safe when no reply channel is wired; a TimeoutError is surfaced, never swallowed.
     * @example
     *   const checkpoint = new Checkpoint({ tools: ['deploy'], waitForReply });
     *   const ok = await checkpoint.confirm('deploy', args);
     */
    constructor(options?: CheckpointOptions);
    tools: Set<string>;
    send: ((question: string, context: any) => any) | null;
    waitForReply: ((context: any) => any) | null;
    shouldAskFn: ((toolName: string, args: any) => boolean) | null;
    timeout: number;
    /**
     * @param {string} toolName - Name of the tool being invoked.
     * @param {any} args - Arguments passed to the tool.
     * @returns {boolean} Whether approval should be requested.
     */
    shouldAsk(toolName: string, args: any): boolean;
    /**
     * Send a question and wait for a reply. Rejects with TimeoutError if `timeout` ms elapse
     * without a reply — the Loop catches this, auto-denies the tool call, and routes the
     * error through loop:error + onError. No silent hangs.
     * @param {string} question - The approval question to send.
     * @param {{tool?: string, [key: string]: any}} [context={}] - Context passed to send and waitForReply.
     * @returns {Promise<string|null>} The user's reply, or null.
     * @throws {Error} `[Checkpoint] send and waitForReply callbacks required` — when callbacks are missing.
     * @throws {TimeoutError} When no reply arrives within `timeout` ms.
     */
    ask(question: string, context?: {
        tool?: string;
        [key: string]: any;
    }): Promise<string | null>;
}