/**
 * Admission for the application command mailbox (WFT-84): validating an offered
 * command, resolving its idempotency identity, enforcing backlog capacity, and
 * committing the record with its indexes and fleet event.
 *
 * Admission is the one transition that also allocates: it advances the mailbox
 * header's FIFO sequence and open count in the same conditional batch as the
 * record itself, so backlog accounting can never drift from the records it
 * describes.
 *
 * @module core/mailbox-admission
 */
import type { ApplicationCommandAdmission, ApplicationCommandInput, MailboxCapacity } from './mailbox-contract.ts';
import { type MailboxRuntime } from './mailbox-internals.ts';
/** Backlog accounting, shared by admission rejection and the public `capacity()`. */
export declare function capacityOf(runtime: MailboxRuntime, open: number, admitted: number): MailboxCapacity;
/**
 * Offer a command to the mailbox.
 *
 * An exact retry of the same idempotency identity returns the original
 * receipt without creating a second command. Reusing the key with a different
 * caller, target, kind, or payload digest returns a conflict and leaves the
 * original command untouched. A full backlog is rejected before anything is
 * persisted.
 */
export declare function admitCommand(runtime: MailboxRuntime, command: ApplicationCommandInput): Promise<ApplicationCommandAdmission>;