/**
 * JSON-safe extractors for XMTP's native remote-attachment content types.
 *
 * Native bindings hand `secret`/`salt`/`nonce` to JS as `Uint8Array`s.
 * `JSON.stringify` turns those into `{}` (or an indexed-object dump on
 * some Node versions), which is useless to a downstream agent. These
 * helpers re-encode the byte fields as **base64**, matching the encoding
 * the `agent serve` `remote-attach` stdin command already uses, so an
 * agent receives and sends remote attachments through one mental model.
 *
 * Decode-only — there is no `Codec` class here because the codec is
 * registered by the underlying `@xmtp/node-bindings` library and the
 * SDK already decodes these messages into the typed objects below.
 * These helpers just normalize them to a stable wire shape.
 */
import { type DecodedMessage } from "@xmtp/node-sdk";
/** JSON-safe view of a single `RemoteAttachmentInfo`. */
export interface RemoteAttachmentInfoJson {
    url: string;
    contentDigest: string;
    scheme: string;
    /** base64 of the encryption secret. */
    secret: string;
    /** base64 of the encryption salt. */
    salt: string;
    /** base64 of the encryption nonce. */
    nonce: string;
    contentLength?: number;
    filename?: string;
}
/** JSON-safe view of a `RemoteAttachment` message payload. */
export type RemoteAttachmentJson = RemoteAttachmentInfoJson;
/** JSON-safe view of a `MultiRemoteAttachment` message payload. */
export interface MultiRemoteAttachmentJson {
    attachments: RemoteAttachmentInfoJson[];
}
/**
 * If the message is a single `xmtp.org/remoteStaticAttachment:1.0`, return
 * the JSON-safe extraction; otherwise undefined.
 */
export declare function extractRemoteAttachment(message: DecodedMessage): RemoteAttachmentJson | undefined;
/**
 * If the message is a `xmtp.org/multiRemoteStaticAttachment:1.0`, return
 * the JSON-safe extraction; otherwise undefined.
 */
export declare function extractMultiRemoteAttachment(message: DecodedMessage): MultiRemoteAttachmentJson | undefined;