import { type ChatContextDigest } from "../shared/schemas/chat-context.schema.js";
export interface ChatSummarizerMessage {
    role: "user" | "assistant";
    content: string;
}
export interface ChatSummarizerInput {
    previousDigest: ChatContextDigest | null;
    newMessages: ChatSummarizerMessage[];
}
/** Pure LLM summarizer; no DB, no events. */
export declare class ChatSummarizer {
    private model;
    constructor();
    /**
     * Summarize a chat session into a bounded structured digest.
     * @param input - Previous digest (or null) and any messages added since.
     * @returns Updated digest, or null on LLM failure / first-time empty input.
     */
    summarize(input: ChatSummarizerInput): Promise<ChatContextDigest | null>;
}