import type { ChatMessage } from "../types.js";
export declare const SYSTEM_TURN_MARKER = "[SYSTEM]";
export declare const REQUEST_CONTEXT_PREFIX = "REQUEST CONTEXT";
export declare function isRequestContextSystemMessage(message: ChatMessage): boolean;
export declare function upsertRequestContextMessage(messages: ChatMessage[], content: string): void;
export declare function normalizeSystemMessages(messages: ChatMessage[]): {
    systemPrompt: string | undefined;
    rest: ChatMessage[];
};
export declare function singleLeadingSystemMessages(messages: readonly ChatMessage[]): ChatMessage[];
export declare function markSystemTurn(content: string): string;
export declare function firstSystemPrompt(messages: ChatMessage[]): string | undefined;