/** @internal
 *  Whether a caught value is the SDK's own suspend signal, which must be
 *  rethrown rather than reported as a step failure.
 *
 *  Both halves of the check can throw on a hostile value: `instanceof` consults
 *  a proxy's `getPrototypeOf` trap, and reading `.name` its `get` trap. This
 *  runs before anything has been checkpointed, so neither may escape — a value
 *  that fights back is simply not a suspend. */
export declare function isSuspendSignal(e: unknown, suspendCtor: Function): boolean;
/** @internal
 *  Serialize a failed `step()` body into the `__wmill_error` marker that task
 *  failures also use, so it can be stored in `completed_steps`.
 *
 *  The record's final shape is decided by the backend (`wac_failure_record`),
 *  which normalizes task failures through the same function; what is built here
 *  is the raw material plus the envelope the backend recognizes. */
export declare function stepErrorMarker(key: string, e: unknown): Record<string, any>;
/** @internal
 *  Rebuild the error a failed task or step throws. The run that produced the
 *  failure and every later replay go through here: a catch is control flow,
 *  `workflow()` re-runs its body from the top every round, so a handler that
 *  branches on the failure it caught must be handed the same thing in every
 *  round or it dispatches different tasks on the way back. */
export declare function taskErrorFromMarker(marker: any, fallbackMessage: string): Error;