import type { OperationEvent, OperationWebhookConfig } from '../types/operations.js';
/** Header that carries a delivery's signature. */
declare const SIGNATURE_HEADER = "x-nexus-signature";
/**
 * Builds the signature for one delivery.
 *
 * The signed value is `${timestamp}.${body}` rather than the body alone, so a captured delivery
 * cannot be replayed indefinitely: a receiver checks the timestamp is recent and the signature
 * covers it, and an attacker cannot move the timestamp without invalidating the digest.
 */
export declare function signOperationWebhook(body: string, secret: string, timestampSeconds: number): string;
/** Options for `verifyOperationWebhook()`. */
export interface VerifyOperationWebhookOptions {
    /** Maximum delivery age in seconds. Defaults to 300. */
    toleranceSeconds?: number;
    /** Current time in seconds, for tests. */
    nowSeconds?: number;
}
/**
 * Verifies a delivery signature.
 *
 * Exported because a receiver needs it: shipping the signing half without the verifying half
 * pushes every consumer into writing their own HMAC comparison, which is exactly the code most
 * likely to be written without a constant-time compare.
 */
export declare function verifyOperationWebhook(body: string, header: string | undefined, secret: string, options?: VerifyOperationWebhookOptions): boolean;
/**
 * Delivers one operation event to a configured endpoint.
 *
 * Throws on a failed delivery so the caller can decide what to do. The runner reports the error
 * through `onWebhookError` and continues: a webhook that a receiver cannot accept must not turn a
 * successful operation into a failed one.
 */
export declare function deliverOperationWebhook(config: OperationWebhookConfig, event: OperationEvent<unknown>, nowSeconds?: number): Promise<void>;
export { SIGNATURE_HEADER as OPERATION_WEBHOOK_SIGNATURE_HEADER };