import type { Message, ToolMessage } from '../types/message/index.js';
/**
 * Clear stale tool OUTPUT in place, without touching the conversation's
 * shape.
 *
 * Compaction was all-or-nothing: once the threshold hit, every older
 * message became a summary and the agent's own reasoning — the decisions,
 * the false starts it learned from, the exact wording of a plan — was
 * paraphrased away with it. That is a heavy price to pay for a context
 * problem that is usually caused by something much dumber: a handful of
 * enormous tool outputs the agent already read, extracted what it needed
 * from, and moved past.
 *
 * Clearing those reclaims most of the same tokens while preserving every
 * message verbatim. It is safe where trimming is not, because the `tool`
 * message stays exactly where it is with the same `toolCallId` — so the
 * `tool_use` ↔ `tool_result` pairing the providers require is untouched by
 * construction. The placeholder tells the model what happened, so a result
 * it turns out to still need is one tool call away rather than lost.
 */
export interface ToolResultEditConfig {
    /**
     * How many of the most recent tool results to leave alone. The agent is
     * usually still working with these, and clearing them buys tokens by
     * forcing an immediate re-read — a net loss.
     */
    readonly keepRecentToolResults?: number;
    /**
     * Don't bother clearing results smaller than this. Below it the
     * placeholder is comparable in size to the output, so the churn buys
     * nothing and costs the model a confusing hole in its history.
     */
    readonly minCharsToClear?: number;
    /** Tools whose output is never cleared, by name. */
    readonly preserveTools?: readonly string[];
}
export declare const DEFAULT_KEEP_RECENT_TOOL_RESULTS = 3;
export declare const DEFAULT_MIN_CHARS_TO_CLEAR = 1000;
export interface ToolResultEditOutcome {
    readonly messages: Message[];
    readonly clearedCount: number;
    /** Payload characters removed, including encoded data; not a token estimate. */
    readonly charsReclaimed: number;
}
/**
 * One result cleared on its own, for a caller that chose it by some
 * other rule than staleness. The same placeholder, the same accounting.
 */
export declare function clearToolResult(tool: ToolMessage, toolName: string): {
    readonly message: ToolMessage;
    readonly charsReclaimed: number;
};
export declare function isClearedToolResult(content: unknown): boolean;
/**
 * Replace the output of old, large tool results with a short placeholder.
 *
 * Returns a NEW array; the input is not mutated. `clearedCount === 0` means
 * nothing was eligible, and the caller should fall through to whatever it
 * would have done anyway.
 */
export declare function clearStaleToolResults(messages: readonly Message[], config?: ToolResultEditConfig): ToolResultEditOutcome;
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