nanocoai/nanoclaw · warning

Delivery batch-preview hook failed

Error message

Delivery batch-preview hook failed

What it means

A registered delivery batch-preview hook threw while previewing a batch of pending outbound messages. The preview is advisory, so delivery proceeds regardless; only the hook's side effect (e.g. dashboards, metrics) is skipped for this batch.

Source

Thrown at src/delivery.ts:214

    if (!existing) return;
    ({ delivered, pending } = existing);
  } catch (err) {
    log.error('Session mailbox delivery failed', {
      agentGroupId: agentGroup.id,
      sessionId: session.id,
      err,
    });
    return;
  }

  for (const hook of batchPreviewHooks) {
    try {
      await hook(
        pending.map(({ kind, content }) => ({ kind, content })),
        session,
      );
    } catch (err) {
      log.warn('Delivery batch-preview hook failed', { sessionId: session.id, err });
    }
  }

  for (const msg of pending) {
    try {
      const platformMsgId = await deliverMessage(msg, session);
      await withExistingMailboxSession(agentGroup.id, session.id, (mailbox) =>
        mailbox.markDelivered(msg.id, platformMsgId ?? null),
      );
      const firstDelivery = delivered.size === 0;
      delivered.add(msg.id);
      deliveryAttempts.delete(msg.id);
      if (msg.kind !== 'system' && msg.channelType !== 'agent') {
        pauseTypingRefreshAfterDelivery(session.id);
        if (msg.kind !== 'task_log') {
          await fanOutboundMessage(
            {
              id: msg.id,

View on GitHub (pinned to 294ef2aee8)

Solutions

1. Identify which registered hook threw from the error detail
2. Fix or disable the offending add-on (e.g. dashboard pusher config)
3. Restart the host after fixing

try { await hook(batch, session); } catch (err) { log.warn(...); /* delivery proceeds */ }

When it happens

Trigger: A hook registered via the batch-preview hook list throws — commonly a pusher with a dead HTTP endpoint or a serialization error on message content.

Common situations: Dashboard/metrics add-on skills whose pusher endpoint is down or whose payload shape changed after an update.

Related errors

• Post-delivery hook failed
• Malformed outbound row — delivering best-effort
• Delivery action denied by guard
• Message delivery failed, will retry
• Unknown system action

AI-assisted analysis of nanocoai/nanoclaw@294ef2aee8 (2026-08-28). Data as JSON: /api/errors/a686f26d5788380a. Report an issue: GitHub.