/**
 * The timestamp pair these helpers derive from.
 *
 * Both stamps are optional here even though `closed_at` is required on
 * `Agents.RunStepClosedEvent`, because not every caller holds a well-typed
 * event: the Redis replay branch reconstructs closures from persisted JSON and
 * legitimately has nothing stronger than "might be a number". Widening the
 * parameter rather than making callers assert keeps the guards below as the
 * single place that decides what is trustworthy — an assertion at a call site
 * would move that decision somewhere it cannot be enforced.
 */
export interface RunStepTimestamps {
    created_at?: number;
    closed_at?: number;
}
/**
 * Below this, a duration is noise rather than information: sub-second tool
 * calls are the common case, and labelling every one of them `· 0.3s` adds a
 * moving number to the end of most cards without telling the reader anything
 * they could act on. Callers use {@link isReportableRunStepDuration} rather
 * than comparing against this directly.
 */
export declare const MIN_REPORTABLE_RUN_STEP_DURATION_MS = 1000;
/**
 * Wall-clock duration of a run step, derived from the terminal
 * `on_run_step_closed` event.
 *
 * Returns `undefined` rather than a fallback whenever the value would be a
 * guess, because a wrong duration is worse than an absent one — an absent one
 * renders nothing, a wrong one is indistinguishable from a real measurement:
 *
 * - `created_at` is optional on the event; emitters that do not know when the
 *   step opened cannot have their duration inferred from anything else.
 * - A negative result means the two timestamps came from clocks that disagree.
 *   That is not hypothetical: since `@librechat/agents` v3.6.0 a step can be
 *   opened in one process and closed in another after a checkpoint resume, so
 *   the two stamps can legitimately originate on different machines.
 * - Non-finite input is treated as absent instead of propagating `NaN` into
 *   rendering.
 *
 * Known limits, accepted rather than guessed at: only the negative direction
 * of clock skew is detectable from a single stamp pair — positive skew
 * inflates the result and cannot be distinguished from a genuinely long
 * step. And the value is wall-clock elapsed between open and close, so a
 * step held open across a suspension (a checkpoint resume, a HITL approval
 * wait) includes that held-open time. Both are properties of the only data
 * available, not derivation bugs.
 */
export declare function getRunStepDurationMs(closed: RunStepTimestamps): number | undefined;
/**
 * Whether a derived duration is worth showing to the reader.
 *
 * This is a presentation judgment, so it belongs at render time only. The
 * stamp sites persist the raw {@link getRunStepDurationMs} value instead of
 * pre-filtering through this — thresholding at write time would bake a
 * display rule into stored data, making "fast" indistinguishable from "not
 * derivable" and unrecoverable if the rule ever changes.
 */
export declare function isReportableRunStepDuration(durationMs?: number): durationMs is number;