Continue-as-new

Temporal caps a run's history; a workflow that loops forever — an entity, a poller, a batch cursor — must periodically continue as new: end the current run and atomically start a fresh one with the same workflow id and a reset history.

import { continueAsNew, makeTemporalWorkflow } from "@springbird/effect-temporal/engine-sandbox";

export const effectLoopDemo = makeTemporalWorkflow(LoopDemo, (payload) =>
  Effect.gen(function* () {
    yield* callActivity(Record, { iteration: payload.iteration });
    if (payload.iteration >= 2) return `done:${payload.iteration}`;
    // Ends this run; the next starts with the carried payload.
    return yield* continueAsNew(LoopDemo, {
      requestId: payload.requestId,
      iteration: payload.iteration + 1,
    });
  }),
);

continueAsNew(workflow, payload) has type Effect<never> — nothing runs after it. The next run receives the payload you pass, so all carried state must be encodable through the payload schema.

It unwinds as a throw

Like Temporal's native API, continue-as-new ends the run by throwing: Effect finalizers and Workflow.withCompensation steps fire on the way out. Call it:

• at iteration boundaries, in tail position;
• outside compensation regions — a compensated step between you and the continueAsNew will compensate as the run unwinds, which is almost never what an iteration boundary means;
• after draining mailboxes (below).

What does not survive the run change

The new run starts with fresh state:

• Mailbox buffers. Messages offered but not yet taken are gone. Drain with pollMailbox into carried state first:

  let pending: Report[] = [];
  while (true) {
    const next = yield* pollMailbox(Reports);
    if (Option.isNone(next)) break;
    pending.push(next.value);
  }
  return yield* continueAsNew(BatchDemo, { ...payload, carried: pending });

• State cells. Cells are per-run: readers see None in the new run until it republishes. Republish early in the body if outside observers poll the cell.

• Pending updates. An update not yet answered fails to its caller when the run ends — answer before continuing.

Memo

Pass a Temporal memo for the next run when you use memos for ops tooling:

yield* continueAsNew(LoopDemo, nextPayload, { memo: { cursor: "2026-08-01" } });