/**
 * Request payload sent to a Web Worker (or passed to {@link executeActivity})
 * describing a single activity execution.
 *
 * Generated by the worker dispatcher and consumed by the activity runner
 * inside the worker.  Callers do not normally construct this directly — it is
 * built by the engine's task-dispatch path.
 *
 * @example
 * ```ts
 * import { executeActivity, type ActivityExecutionRequest } from '@lostgradient/weft';
 *
 * const request: ActivityExecutionRequest = {
 *   operationId: crypto.randomUUID(),
 *   activityName: 'sendEmail',
 *   input: { to: 'user@example.com' },
 *   attempt: 1,
 * };
 * const result = await executeActivity(request, async (input) => {
 *   return `sent to ${(input as { to: string }).to}`;
 * });
 * console.log(result.status); // 'completed'
 * ```
 */
export interface ActivityExecutionRequest {
    operationId: string;
    activityName: string;
    input: unknown;
    attempt: number;
    workflowExecutionToken?: string;
    activityAttemptToken?: string;
}
/**
 * Result payload returned by {@link executeActivity} and posted back by the
 * Web Worker after activity execution.
 *
 * Check `status` first: `'completed'` means `value` holds the return value;
 * `'failed'` means `error` holds a human-readable failure message.  The
 * `operationId` mirrors the request so the dispatcher can match results.
 *
 * @example
 * ```ts
 * import { executeActivity, type ActivityExecutionResult } from '@lostgradient/weft';
 *
 * const result: ActivityExecutionResult = await executeActivity(
 *   { operationId: 'op-1', activityName: 'add', input: [1, 2], attempt: 1 },
 *   async (input) => (input as number[])[0]! + (input as number[])[1]!,
 * );
 *
 * if (result.status === 'completed') {
 *   console.log(result.value); // 3
 * }
 * ```
 */
export interface ActivityExecutionResult {
    operationId: string;
    status: 'completed' | 'failed';
    value?: unknown;
    error?: string;
    /** Error constructor name used by retry classification and diagnostics. */
    errorName?: string;
}
/**
 * Executes an activity function with structured error handling and optional
 * abort-signal support.
 *
 * Returns a resolved {@link ActivityExecutionResult} regardless of whether the
 * function throws — failures are caught and returned as `{ status: 'failed' }`.
 * If `signal` is already aborted before execution begins, the function is
 * skipped and a failed result is returned immediately.
 *
 * @example
 * ```ts
 * import { executeActivity } from '@lostgradient/weft';
 *
 * const result = await executeActivity(
 *   {
 *     operationId: 'op-abc',
 *     activityName: 'greet',
 *     input: { name: 'World' },
 *     attempt: 1,
 *   },
 *   async (input) => `Hello, ${(input as { name: string }).name}!`,
 * );
 * console.log(result.status); // 'completed'
 * console.log(result.value);  // 'Hello, World!'
 * ```
 */
export declare function executeActivity(request: ActivityExecutionRequest, activityFunction: (...arguments_: unknown[]) => unknown, signal?: AbortSignal): Promise<ActivityExecutionResult>;