import { ModelMessage } from '@tanstack/ai';
export interface BuiltAcpPrompt {
    prompt: string;
    /** Harness session id to resume, when the caller threaded one through. */
    resume?: string;
}
/**
 * Convert TanStack chat history into a harness prompt + resume inputs.
 *
 * With a `sessionId`, the harness already holds the conversation context, so
 * only the trailing user message is sent and the session is resumed. Without
 * one, prior user/assistant turns are flattened into a plain-text transcript
 * preamble (tool messages and tool-call-only assistant turns are
 * harness-internal noise and are skipped; prompts are text-only).
 *
 * Shared default for ACP harness adapters; pass a custom `buildPrompt` to
 * {@link acpCompatible} to override.
 */
export declare function buildAcpPrompt(messages: Array<ModelMessage>, sessionId: string | undefined, harnessName?: string): BuiltAcpPrompt;