import type { AckRecord, MailboxMessage, MailboxMessageType } from './mailbox-types.js';
/** Normalize message types emitted by pre-union mailbox builds. */
export declare function normalizeMailboxMessageType(value: unknown): MailboxMessageType;
/**
 * Resolve the message type for a SEND operation, applying default-type logic
 * and cross-field validation.
 *
 * ** Default-type rules ** (mirror the `mail_send` tool's logic):
 * - When `type` is explicitly provided, use it directly.
 * - When `type` is omitted AND the resolved `to` is `"*"` or starts with
 *   `"@session:"`, the default is `"broadcast"`.
 * - Otherwise (omitted, non-broadcast target), the default is `"note"`.
 *
 * **Send-side validation** (from `validateSendType`):
 * - `control` is rejected — it is reserved for runtime use.
 * - `assign` and `steer` with `to="*"` are rejected — these types require a
 *   specific recipient.
 *
 * @returns The resolved type (explicit or defaulted).
 * @throws {TypeError} When the type is reserved or the (type, to) pair is
 *   semantically invalid.
 */
export declare function resolveSendType(type: MailboxMessageType | undefined, to: string): MailboxMessageType;
/**
 * Resolve the message type for a SEND, returning a descriptive error instead
 * of throwing. Convenience wrapper for use in tool handlers where a thrown
 * TypeError would be awkward to catch.
 *
 * Returns `{ ok: true, type }` on success, or `{ ok: false, error }` when
 * the (type, to) pair is invalid.
 */
export declare function resolveSendTypeSafe(type: MailboxMessageType | undefined, to: string): {
    ok: true;
    type: MailboxMessageType;
} | {
    ok: false;
    error: string;
};
/** Parse, migrate, and structurally validate one persisted mailbox message. */
export declare function parseMailboxMessage(value: unknown): MailboxMessage;
/** Parse one JSONL line and validate the decoded mailbox message. */
export declare function parseMailboxMessageLine(line: string): MailboxMessage;
/**
 * Check if a parsed JSONL value is an append-only ack record (not a message).
 * Ack records carry a `__ack: true` discriminator.
 */
export declare function isAckRecord(value: unknown): value is AckRecord;
/**
 * Parse one JSONL line, returning either a MailboxMessage or an AckRecord.
 * Returns null when the line is neither (corrupt/malformed).
 */
export declare function parseMailboxLine(line: string): MailboxMessage | AckRecord | null;
/**
 * Apply an ack record's effects to a MailboxMessage in-place.
 * This mutates the message object (readBy, completed, completedBy, completedAt,
 * outcome, deletedAt, deletedBy).
 */
export declare function applyAckToMessage(msg: MailboxMessage, ack: AckRecord): void;
/**
 * Serialize an ack record to a JSONL line.
 */
export declare function serializeAckRecord(ack: AckRecord): string;
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