import type * as smoltalk from "smoltalk";
export type CompactionConfig = {
    trigger: "token" | "messages";
    threshold: number;
};
export declare function shouldCompact(messages: smoltalk.Message[], config: CompactionConfig): boolean;
/**
 * Find a safe split point that respects message boundaries.
 *
 * Walk forward from the midpoint until the boundary message is a `user`
 * or `assistant` message. A `tool` reply is never a boundary — keeping
 * the thread from a tool reply onward would orphan it from the
 * `assistant` message carrying its `tool_calls`. Any other role is safe:
 * tool replies always follow their assistant message, so keeping from an
 * assistant message keeps its replies with it. Accepting assistant
 * boundaries matters for agentic tool loops, where the only user message
 * is the opening request and everything after is assistant/tool traffic.
 *
 * Returns the index of the message that should be the FIRST kept message
 * (i.e., everything before this index is compacted).
 *
 * Returns -1 if no clean boundary exists (caller should skip compacting).
 */
export declare function findCompactionSplitPoint(messages: smoltalk.Message[]): number;
export declare function buildCompactionPrompt(messages: smoltalk.Message[]): string;
export declare function buildMergeSummaryPrompt(existingSummary: string, newSummary: string): string;