import type { Api, Model, SimpleStreamOptions } from '@earendil-works/pi-ai/compat';
export declare const COMPACTION_CONTEXT_MARGIN = 4096;
export declare const COMPACTION_REPAIR_RESERVE = 1024;
export declare class CompactionRequestError extends Error {
    readonly kind: 'length' | 'empty' | 'budget' | 'provider' | 'timeout';
    constructor(kind: 'length' | 'empty' | 'budget' | 'provider' | 'timeout', message: string);
}
export declare function compactionOutputLimit(model: Model<Api>, configured: number): number;
/** Start large prompts closer to their likely delta size while retaining room to double on truncation. */
export declare function initialCompactionOutputLimit(systemPrompt: string, prompt: string, outputLimit: number): number;
export declare function compactionPromptFits(model: Model<Api>, systemPrompt: string, prompt: string, outputLimit: number): boolean;
/** Bound the final provider payload, including adapters that add a thinking budget. */
export declare function compactionPayloadGuard(limit: number, onBudget: (actual: number) => void): NonNullable<SimpleStreamOptions['onPayload']>;
export declare function isPermanentCompactionError(error: unknown): boolean;