ruvnet/ruflo · error

anchor task requires non-empty string labels

Error message

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

What it means

Every anchor task must have a `labels` array containing at least one non-blank string (every entry checked with trim). Labels are the expected-results ground truth the human-relevance delta is computed from; a missing, empty, or malformed labels array invalidates the whole measurement, so the file is rejected.

Solutions

1. Give each task a non-empty array of expected-result strings (e.g. relevant file paths or keywords)
2. Wrap bare-string labels in an array: `labels: "src/api.ts"` becomes `labels: ["src/api.ts"]`
3. Filter out blank entries when generating the file

Example fix

// before
{ "id": "t1", "q": "...", "labels": "src/api.ts" }

// after
{ "id": "t1", "q": "...", "labels": ["src/api.ts", "src/routes/api.ts"] }

function labelsFilled(tasks: Array<{ id: string; labels?: unknown }>): string[] {
  return tasks
    .filter((t) => !Array.isArray(t.labels) || t.labels.length === 0 || t.labels.some((l) => typeof l !== 'string' || !l.trim()))
    .map((t) => t.id);
}

interface TaskLike { id?: unknown; q?: unknown; labels?: unknown; }

function hasLabels(task: unknown): task is TaskLike & { labels: string[] } {
  const l = (task as TaskLike)?.labels;
  return Array.isArray(l) && l.length > 0 && l.every((x) => typeof x === 'string' && x.trim().length > 0);
}

// Usage: const bad = tasks.filter((t) => !hasLabels(t)).map((t) => t.id);

try {
  return loadEffectiveFlywheelAnchor(root, opts);
} catch (e) {
  if (e instanceof Error && /anchor task .+ requires non-empty string labels$/.test(e.message)) {
    const id = e.message.match(/anchor task (.+) requires/)?.[1];
    throw new Error(`Task '${id}' needs labels: ['expected/file.ts', ...] — expected results for the query.`);
  }
  throw e;
}

When it happens

Trigger: `labels` absent, not an array (`labels: "api"`), an empty array, or an array containing blank or non-string entries such as `["", " "]` or `[1]`.

Common situations: Hand-authored anchors forgetting the labels key; single-label shorthand written as a bare string; CSV exports producing empty cells as empty strings.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

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

AI-assisted analysis of ruvnet/ruflo@2602b642d9 (2026-08-18). Data as JSON: /api/errors/70e62f9ff600df4c. Report an issue: GitHub.

Appendix: source

Thrown at v3/@claude-flow/cli/src/services/harness-project-anchor.ts:108

  };
  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 2602b642d9)