/**
 * @license
 * Copyright 2026 Steven Roussey <sroussey@gmail.com>
 * SPDX-License-Identifier: Apache-2.0
 */
import type { ITask } from "@workglow/task-graph";
/**
 * Wall-clock for a usage fragment. While the task is still running — or a
 * leftover `completedAt` from a prior run of a reused node is older than the
 * current `startedAt` — use `nowMs`. Otherwise freeze at `completedAt`.
 */
export declare function appendUsageDuration(usageText: string, task: ITask, nowMs: number): string;
/** True when the usage line should keep ticking wall-clock. */
export declare function usageLineNeedsTick(usageText: string, task: ITask): boolean;
/**
 * Per-task usage line: directional token counts plus a cost when the model's
 * rate card (or a provider-stated `extra.cost`) can price the spend, plus live
 * wall-clock when a usage fragment is already showing.
 */
export declare function useTaskUsageLine(task: ITask): string;