import type { CanonMessage } from './types.js';
/**
 * Project a CanonMessage to a single text representation suitable as a
 * baseline for plugins that feed messages to an LLM as plain text.
 *
 * Plugins that compose richer prompts (placeholders, capability hints,
 * native vision input) layer on top of this — the goal here is only to
 * guarantee that no contentType is ever silently dropped to an empty
 * string. Adding a new contentType to CanonMessage and forgetting to
 * handle it here surfaces in this file's tests, not as a silent
 * regression in every consumer plugin.
 */
export declare function formatCanonMessageAsText(message: Pick<CanonMessage, 'contentType' | 'text' | 'attachments' | 'contactCard' | 'interaction'>): string;