/**
 * Idempotency Cache for MCP Mutation Tools
 *
 * Prevents duplicate frames from being created when AI agents retry tool calls
 * due to network flakiness or tooling issues. Based on request_id.
 *
 * Design:
 * - In-memory cache with configurable TTL (default: 24 hours)
 * - Stores complete MCPResponse for each request_id
 * - Automatic cleanup of expired entries on get/set operations
 * - Thread-safe for single-process MCP servers
 *
 * Inspired by LexSona's MCP idempotency pattern.
 */
import type { MCPResponse } from "./server.js";
/**
 * Idempotency cache for MCP mutation tools
 */
export declare class IdempotencyCache {
    private cache;
    private readonly ttlMs;
    /**
     * Create a new idempotency cache
     * @param ttlMs Time-to-live in milliseconds (default: 24 hours)
     */
    constructor(ttlMs?: number);
    /**
     * Get cached response for a request_id
     * @param requestId The request ID to look up
     * @returns Cached response if found and not expired, undefined otherwise
     */
    getCached(requestId: string): MCPResponse | undefined;
    /**
     * Store a response in the cache
     * @param requestId The request ID to cache
     * @param response The MCP response to cache
     */
    setCached(requestId: string, response: MCPResponse): void;
    /**
     * Remove all expired entries from the cache
     * Called automatically on get/set operations
     */
    private clearExpired;
    /**
     * Get current cache size (for debugging/testing)
     */
    size(): number;
    /**
     * Clear all cached entries (for testing)
     */
    clear(): void;
}