/**
 * slidingWindow — keep the last N turns, drop what is older.
 *
 * Pattern: WindowStrategy implementation. Its own module, registering
 *          nothing at import.
 * Role:    core/ layer.
 * Emits:   N/A — the stage emits, records and costs; this file decides.
 *
 * The market's simplest window policy (LangChain's `trim_messages`, the
 * "last N messages" every framework ships). Two things are different here:
 *
 *   1. **It refuses by name.** It goes through the SAME turn segmentation and
 *      the SAME refusal engine as compaction, so it will not drop half of a
 *      `tool_use` / `tool_result` pair, will not drop an unanswered tool call
 *      whose answer may still arrive, will not drop the tool a paused run is
 *      waiting on or a pending check-in, and cannot touch the system
 *      envelope. Message-counting trimmers split those pairs and the vendor
 *      rejects the request; this one steps over them and says so in the
 *      record.
 *   2. **It says what it dropped.** Every dropped message is an eviction
 *      event with its measured lifetime, and the record names the stage ids
 *      the messages came from. The turns themselves stay in the commit log,
 *      byte for byte.
 *
 * It triggers on turn COUNT, not tokens — so it needs no summarizer, makes no
 * LLM call, and runs on ANY provider, including the ones that report no usage
 * at all. Nothing here is unmeasurable, so nothing here throws.
 */
import type { WindowStrategy } from '../strategy.js';
import type { SlidingWindowOptions } from '../types.js';
/** `WindowRecord.strategy` written by every record this strategy files. */
export declare const SLIDING_WINDOW = "sliding-window";
/**
 * Keep the most recent `keepRecentTurns` turns in the live window and drop
 * the older ones — except anything that refuses.
 *
 * @example
 * ```ts
 * import { Agent, slidingWindow } from 'agentfootprint';
 * import { ollama } from 'agentfootprint/providers';
 *
 * // Works on a provider that reports no usage at all: the trigger is turns.
 * const agent = Agent.create({ provider: ollama('llama3.2'), model: 'llama3.2' })
 *   .window(slidingWindow({ keepRecentTurns: 12 }))
 *   .build();
 * ```
 */
export declare function slidingWindow(options: SlidingWindowOptions): WindowStrategy;