import type { Message } from "../types.js";
/** Input payload for AG-UI before stream message. */
export type AgUiBeforeStreamMessageInput = Omit<Message, "id"> & {
    id?: string;
    /**
     * Mark a system message as trusted server-generated content.
     *
     * By default, system-role messages from `beforeStream` hooks are downgraded
     * to user-role with boundary markers to prevent prompt injection via RAG
     * content. Set `trusted: true` only for server-generated instructions.
     */
    trusted?: boolean;
};
/** Context for AG-UI before stream. */
export interface AgUiBeforeStreamContext {
    request: Request;
    messages: Message[];
    context: Record<string, unknown>;
    lastUserText: string;
}
/** Result returned from AG-UI before stream. */
export interface AgUiBeforeStreamResult {
    prepend?: AgUiBeforeStreamMessageInput[];
    append?: AgUiBeforeStreamMessageInput[];
    replaceMessages?: AgUiBeforeStreamMessageInput[];
    context?: Record<string, unknown>;
}
/** Public API contract for AG-UI before stream. */
export type AgUiBeforeStream = (input: AgUiBeforeStreamContext) => void | Response | AgUiBeforeStreamResult | Promise<void | Response | AgUiBeforeStreamResult>;
export declare function extractLastUserText(messages: Array<{
    role: string;
    parts: unknown[];
}>): string;
export declare function applyBeforeStreamResult(baseMessages: Message[], result: AgUiBeforeStreamResult | undefined): Message[];
//# sourceMappingURL=before-stream.d.ts.map