What causes "Questions must be greater than 0" in mastra-ai/mastra?

Pass a positive integer for `questions`, e.g. new QuestionAnswerExtractor({ questions: 5 }).

Questions must be greater than 0

Error message

Questions must be greater than 0

What it means

The QuestionAnswerExtractor constructor validates the `questions` option: if provided and less than 1, it throws immediately instead of proceeding with an invalid count of questions to generate per chunk. The default is 5 when omitted.

Source

Thrown at packages/rag/src/document/extractors/questions.ts:35

/**
 * Extract questions from a list of nodes.
 */
export class QuestionsAnsweredExtractor extends BaseExtractor {
  llm: MastraLanguageModel | MastraLegacyLanguageModel;
  questions: number = 5;
  promptTemplate: QuestionExtractPrompt;
  embeddingOnly: boolean = false;

  /**
   * Constructor for the QuestionsAnsweredExtractor class.
   * @param {MastraLanguageModel} llm MastraLanguageModel instance.
   * @param {number} questions Number of questions to generate.
   * @param {QuestionExtractPrompt['template']} promptTemplate Optional custom prompt template (should include {context}).
   * @param {boolean} embeddingOnly Whether to use metadata for embeddings only.
   */
  constructor(options?: QuestionAnswerExtractArgs) {
    if (options?.questions && options.questions < 1) throw new Error('Questions must be greater than 0');

    super();

    this.llm = options?.llm ?? baseLLM;
    this.questions = options?.questions ?? 5;
    this.promptTemplate = options?.promptTemplate
      ? new PromptTemplate({
          templateVars: ['numQuestions', 'context'],
          template: options.promptTemplate,
        }).partialFormat({
          numQuestions: '5',
        })
      : defaultQuestionExtractPrompt;
    this.embeddingOnly = options?.embeddingOnly ?? false;
  }

  /**
   * Extract answered questions from a node.

View on GitHub (pinned to 75dd419e61)

Solutions

Pass a positive integer for `questions`, e.g. new QuestionAnswerExtractor({ questions: 5 }).
If the value is computed, clamp it: Math.max(1, computedCount).
If you don't need a specific count, omit `questions` to use the default of 5.

Example fix

// before
new QuestionAnswerExtractor({ questions: config.questionCount }); // questionCount = 0
// after
new QuestionAnswerExtractor({ questions: Math.max(1, config.questionCount) });

Defensive patterns

Strategy: validation

Validate before calling

const questions = config.questionCount ?? 5;
if (!Number.isInteger(questions) || questions < 1) throw new RangeError(`questions must be >= 1, got ${questions}`);
const extractor = new QuestionAnswerExtractor({ questions });

Try / catch

try {
  new QuestionAnswerExtractor({ questions });
} catch (e) {
  if (e instanceof Error && e.message === 'Questions must be greater than 0') {
    extractor = new QuestionAnswerExtractor({ questions: 5 });
  } else throw e;
}

Prevention

Clamp computed counts with Math.max(1, n).
Centralize extractor option parsing and validate before construction.
Add a unit test for zero/negative question counts.

When it happens

Trigger: new QuestionAnswerExtractor({ questions: 0 }) or any negative number, e.g. { questions: -3 }.

Common situations: Computing the question count from config (e.g. Math.floor of a ratio that rounds to 0), parsing user input from CLI/env, or off-by-one loops that end at 0.

Understand the failure class

Background: "Invalid configuration value" and "Unsupported/Unknown setting value" errors: why libraries reject your config strings, numbers, and types — this error's family across 30 libraries.

Related errors

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/d18576785f944f39. Report an issue: GitHub.