import type { AgentMessage } from "@mariozechner/pi-agent-core";
export declare const CHARS_PER_TOKEN_ESTIMATE = 4;
export declare const TOOL_RESULT_CHARS_PER_TOKEN_ESTIMATE = 2;
export type MessageCharEstimateCache = WeakMap<AgentMessage, number>;
export declare function isToolResultMessage(msg: AgentMessage): boolean;
export declare function getToolResultText(msg: AgentMessage): string;
export declare function createMessageCharEstimateCache(): MessageCharEstimateCache;
export declare function estimateMessageCharsCached(msg: AgentMessage, cache: MessageCharEstimateCache): number;
export declare function estimateContextChars(messages: AgentMessage[], cache: MessageCharEstimateCache): number;
export declare function invalidateMessageCharsCacheEntry(cache: MessageCharEstimateCache, msg: AgentMessage): void;