jackwener/OpenCLI · error · CommandExecutionError

Midjourney action is ambiguous; ${candidates.length} derived

Error message

Midjourney action is ambiguous; ${candidates.length} derived jobs matched parent ${parentJobId}

What it means

After submitting a derived action (upscale/vary/reroll) on a parent job, the library polls for exactly one new child job enqueued at/after the action time. If more than one candidate child job matches the parent and timing window, CommandExecutionError is thrown listing the candidate URLs, since picking one would be a guess.

Source

Thrown at clis/midjourney/utils.js:504

      if (consecutivePollFailures >= 3) throw error;
      if (!(await waitForNextPoll(page, deadline, 1.5))) break;
      continue;
    }
    candidates = recent.filter((row) => {
      const id = String(row?.id || '').toLowerCase();
      const parent = String(row?.parent_id || '').toLowerCase();
      const enqueuedAt = Date.parse(String(row?.enqueue_time || ''));
      return UUID_RE.test(id)
        && !baselineIds.has(id)
        && parent === String(parentJobId).toLowerCase()
        && Number.isFinite(enqueuedAt)
        && enqueuedAt >= submittedAtMs - 5000;
    });
    if (candidates.length === 1) return String(candidates[0].id).toLowerCase();
    if (!(await waitForNextPoll(page, deadline, 1.5))) break;
  } while (true);
  if (candidates.length > 1) {
    throw new CommandExecutionError(
      `Midjourney action is ambiguous; ${candidates.length} derived jobs matched parent ${parentJobId}`,
      candidates.map((row) => jobUrl(row.id)).join(', '),
    );
  }
  throw new TimeoutError('Midjourney derived job submission', timeoutSeconds, `No new child job appeared for ${parentJobId}.`);
}

export async function waitForCompletedJob(page, jobId, timeoutSeconds) {
  const deadline = Date.now() + timeoutSeconds * 1000;
  let lastStatus = 'unknown';
  do {
    const job = await fetchJobStatus(page, jobId, { allowMissing: true });
    if (job) {
      lastStatus = String(job.current_status || job.status || 'unknown').toLowerCase();
      if (lastStatus === 'completed') return job;
      if (['failed', 'cancelled', 'canceled', 'error'].includes(lastStatus)) {
        throw new CommandExecutionError(`Midjourney job ${jobId} ended with status "${lastStatus}"`);
      }

View on GitHub (pinned to 49907e53dc)

Solutions

Inspect the candidate job URLs in the error and continue with the intended child ID directly (e.g. via waitForCompletedJob).
Avoid re-running the action command after a timeout — the first run may have succeeded; check the parent's children on midjourney.com first.
Ensure no concurrent sessions are issuing actions on the same parent job.
Wait for unrelated child jobs from that parent to complete before re-attempting, so the matching window is unambiguous.

Defensive patterns

Strategy: validation

Validate before calling

// ensure no child jobs already exist from a prior attempt before re-issuing the action
const children = await fetchJobStatuses(page, recentJobIds).catch(() => []);
const priorChildren = children.filter((j) => String(j.parent_job_id || j.job_id || '') === parentJobId);
if (priorChildren.length > 0) {
  console.warn(`${priorChildren.length} child job(s) already exist for ${parentJobId}; track one by ID instead of re-running the action.`);
}

Try / catch

try {
  const childId = await deriveChildJobId(page, parentJobId, action);
} catch (e) {
  const m = String(e.message).match(/ambiguous; (\d+) derived jobs/);
  if (m) {
    console.error('Choose the correct child from the listed URLs and continue with that ID.');
  } else throw e;
}

Prevention

Do not re-run action commands after a timeout without checking for existing children
Serialize all actions on a given parent within one session
Record child job IDs as soon as they are resolved for later retries
Wait for unrelated sibling jobs to leave the enqueued window before re-attempting

When it happens

Trigger: Calling the derived-job flow when candidates.length > 1 — e.g. the same action was triggered twice (double-click/rerun), another session performed actions on the same parent, or multiple children legitimately spawned within the timing tolerance (submittedAtMs - 5000).

Common situations: Retrying a failed action command after the first actually succeeded (two children exist); parallel CLI sessions acting on the same parent image; grid actions generating multiple jobs within the window.

Related errors

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/088ea6511306680d. Report an issue: GitHub.