/**
 * Request-time pruning of stale tool results.
 *
 * Large tool outputs (a 50 KB `read`, a long `bash` log) are only useful for a
 * few turns. Long before compaction triggers they are dead weight in every
 * provider request. This module replaces the content of old, large tool
 * results with a short placeholder right before the request is built.
 *
 * It is a pure transform: the session file, compaction, and in-memory history
 * are never touched. The model can re-read or re-run whenever it needs the
 * original output.
 */
import type { AgentMessage } from "@elyracode/agent-core";
export interface ContextPruningSettings {
    /** Master switch. When false, messages pass through untouched. */
    enabled: boolean;
    /** A tool result is stale once this many assistant messages follow it. */
    keepRecentTurns: number;
    /** Only prune tool results whose text content is at least this long. */
    minChars: number;
}
export declare const DEFAULT_CONTEXT_PRUNING: ContextPruningSettings;
export interface ContextPruningStats {
    prunedMessages: number;
    charsRemoved: number;
}
/**
 * Replace the content of stale, large, non-error tool results with a short
 * placeholder. Input messages are never mutated. Untouched messages are
 * returned by reference so the cached prompt prefix stays byte-identical.
 * When nothing is pruned the input array itself is returned.
 */
export declare function pruneStaleToolResults(messages: readonly AgentMessage[], settings: ContextPruningSettings): AgentMessage[];
/** Dry run of {@link pruneStaleToolResults} that only reports what would be removed. */
export declare function countPrunableChars(messages: readonly AgentMessage[], settings: ContextPruningSettings): ContextPruningStats;
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