/**
 * Plan-step compaction policy (port of NVlabs/SoL-Pi commit 4101906, as
 * re-implemented in bench/baseline/32-plan-step-compaction.mjs arm B).
 *
 * Checked at turn end after a plan step is newly completed. Compacting turns a
 * big cached prefix into a small summary: every later request re-reads less
 * (saving), but the new prefix must be re-written to cache once at r× the read
 * price. Compact iff that write cost is repaid within the expected number of
 * remaining requests (horizon). Pure — the session owns the bookkeeping.
 */
/** SoL-Pi default cache write/read price ratio. GPT-6.1 Sol's real ratio is 25. */
export declare const DEFAULT_CACHE_WRITE_READ_RATIO = 12.5;
/** Recent tail kept verbatim by compaction (SoL-Pi keep budget). */
export declare const PLAN_STEP_KEEP_TOKENS = 20000;
/** Approximate size of the summary that replaces the archive. */
export declare const PLAN_STEP_SUMMARY_TOKENS = 1000;
/** Within this many tokens of the window, leave it to the size trigger. */
export declare const PLAN_STEP_WINDOW_GUARD = 16384;
export interface PlanStepCompactionInput {
    /** Current context size in tokens. */
    contextTokens: number;
    /** Tokens of the recent tail compaction keeps verbatim. */
    keptTailTokens: number;
    contextWindow: number;
    /** Cache write price / cache read price. */
    cacheWriteReadRatio: number;
    stepsCompleted: number;
    stepsRemaining: number;
    /** Requests spent inside completed steps (for mean requests-per-step). */
    requestsInCompletedSteps: number;
    /** All requests so far (for mean context growth per request). */
    requests: number;
    /** Context tokens grown across `requests`. */
    grownTokens: number;
    /** Successful compactions so far this session. */
    priorCompactions: number;
    /** Unpaid cache-write cost (cache-read token units) from earlier compactions. */
    writeCostBalance: number;
    /** Requests since the last compaction (undefined when none yet). */
    requestsSinceLastCompaction?: number;
}
export interface PlanStepCompactionDecision {
    compact: boolean;
    reason: string;
}
export declare function decidePlanStepCompaction(input: PlanStepCompactionInput): PlanStepCompactionDecision;