ruvnet/ruflo · error · Error

anchor task ${task.id} requires non-empty string labels

Error message

anchor task ${task.id} requires non-empty string labels

What it means

Thrown per-task when task.labels is missing, not an array, an empty array, or contains any element that is not a non-empty string (after trim). Labels are the expected-relevance markers the flywheel uses to score retrieval, so each task must carry at least one meaningful label. The check is strict: a labels value of ["", " "] fails because every element must be a non-blank string.

Source

Thrown at v3/@claude-flow/cli/src/services/harness-project-anchor.ts:97

  };
  if (parsed.schemaVersion && parsed.schemaVersion !== PROJECT_ANCHOR_SCHEMA) {
    throw new Error(`unsupported flywheel anchor schema: ${parsed.schemaVersion}`);
  }
  if (!Array.isArray(parsed.tasks) || parsed.tasks.length < 4) {
    throw new Error('project flywheel anchor requires at least 4 labelled tasks');
  }
  const ids = new Set<string>();
  for (const [index, task] of parsed.tasks.entries()) {
    if (!task || typeof task.id !== 'string' || !/^[A-Za-z0-9._-]{1,128}$/.test(task.id)) {
      throw new Error(`invalid anchor task id at index ${index}`);
    }
    if (ids.has(task.id)) throw new Error(`duplicate anchor task id: ${task.id}`);
    ids.add(task.id);
    if (typeof task.q !== 'string' || task.q.trim().length === 0) {
      throw new Error(`anchor task ${task.id} has no query`);
    }
    if (!Array.isArray(task.labels) || task.labels.length === 0 || task.labels.some((label) => typeof label !== 'string' || !label.trim())) {
      throw new Error(`anchor task ${task.id} requires non-empty string labels`);
    }
  }
  return { version: parsed.version ?? 'project-anchor-v1', tasks: parsed.tasks };
}

function toSelection(
  path: string,
  expectedHash: string,
): FlywheelAnchorSelection {
  const parsed = parseTasks(path);
  const actualHash = humanEvalHash(parsed.tasks);
  if (actualHash !== normalizeHash(expectedHash)) {
    throw new Error(`project flywheel anchor hash mismatch (got ${actualHash}, pinned ${normalizeHash(expectedHash)})`);
  }
  return {
    version: parsed.version,
    anchorRef: actualHash,
    source: 'project',

View on GitHub (pinned to 6b01dc5a68)

Solutions

1. Ensure labels is an array of at least one non-empty string, e.g. ["auth", "middleware"].
2. Filter out null/blank entries when generating labels: labels.filter(l => typeof l === 'string' && l.trim()).
3. Verify Array.isArray(task.labels) && task.labels.length > 0 for every task before saving.

Example fix

// before
{"id":"t1","q":"...","labels":"auth"}
// after — wrap in an array, all non-empty strings
{"id":"t1","q":"...","labels":["auth"]}

function assertLabels(tasks: { id: string; labels?: unknown }[]): void {
  for (const t of tasks) {
    const labels = t.labels;
    if (!Array.isArray(labels) || labels.length === 0
        || labels.some(l => typeof l !== 'string' || !l.trim())) {
      throw new Error(`task ${t.id} has invalid labels`);
    }
  }
}

function hasValidLabels(task: unknown): boolean {
  if (typeof task !== 'object' || task === null) return false;
  const labels = (task as { labels?: unknown }).labels;
  return Array.isArray(labels) && labels.length > 0
    && labels.every(l => typeof l === 'string' && l.trim().length > 0);
}

try {
  loadEffectiveFlywheelAnchor(root, opts);
} catch (e) {
  if (e instanceof Error && /requires non-empty string labels/.test(e.message)) {
    const id = e.message.match(/task (.+?) requires/)?.[1];
    // fix that task's labels array, then retry
  }
  throw e;
}

When it happens

Trigger: A task object where labels is undefined, a string instead of an array, [], or an array containing non-string values (numbers, nulls, objects) or blank strings. The some() predicate fails on the first offending element.

Common situations: Using a single label string instead of a one-element array (labels: "auth" vs labels: ["auth"]); an auto-labeller that emitted nulls for unmatched tasks; copying labels from a CSV that introduced empty trailing elements; forgetting the field on tasks added late.

Related errors

• project flywheel anchor requires at least 4 labelled tasks
• invalid anchor task id at index ${index}
• duplicate anchor task id: ${task.id}
• anchor task ${task.id} has no query
• flywheel anchor manifest requires path and sha256

AI-assisted analysis of ruvnet/ruflo@6b01dc5a68 (2026-08-12). Data as JSON: /api/errors/70e62f9ff600df4c. Report an issue: GitHub.