mastra-ai/mastra · error · MastraError

INVALID_SCORER_THRESHOLD

INVALID_SCORER_THRESHOLD

Error message

${label} threshold for scorer "${scorerId}" must be a finite number between 0 and 1, got ${value}

What it means

An INVALID_SCORER_THRESHOLD MastraError (domain SCORER, category USER) thrown by validateThresholdBound when a configured scorer threshold is not a finite number in [0, 1]. Thresholds compare scores to decide pass/fail, so out-of-range or non-finite values are rejected at configuration time.

Source

Thrown at packages/core/src/evals/thresholds.ts:34

export function checkThresholdPassed(score: number, threshold: ThresholdConfig): boolean {
  if (!Number.isFinite(score)) {
    return false;
  }
  if (typeof threshold === 'number') {
    return score >= threshold;
  }
  if (threshold.min !== undefined && score < threshold.min) return false;
  if (threshold.max !== undefined && score > threshold.max) return false;
  return true;
}

export function isScorerWithThreshold<TScorer>(entry: ScorerEntry<TScorer>): entry is ScorerWithThreshold<TScorer> {
  return typeof entry === 'object' && entry !== null && 'scorer' in entry && 'threshold' in entry;
}

function validateThresholdBound(value: number, label: string, scorerId: string): void {
  if (!Number.isFinite(value) || value < 0 || value > 1) {
    throw new MastraError({
      domain: 'SCORER',
      id: 'INVALID_SCORER_THRESHOLD',
      category: 'USER',
      text: `${label} threshold for scorer "${scorerId}" must be a finite number between 0 and 1, got ${value}`,
    });
  }
}

export function validateThresholdConfig(threshold: ThresholdConfig, scorerId: string): void {
  if (typeof threshold === 'number') {
    validateThresholdBound(threshold, 'Minimum', scorerId);
    return;
  }
  if (typeof threshold !== 'object' || threshold === null || Array.isArray(threshold)) {
    throw new MastraError({
      domain: 'SCORER',
      id: 'INVALID_SCORER_THRESHOLD',
      category: 'USER',

View on GitHub (pinned to 75dd419e61)

Solutions

1. Set the threshold to a finite number between 0 and 1 (e.g. 0.7, not 70)
2. If loading from config/env, parse and clamp/validate: Number.isFinite(v) && v >= 0 && v <= 1
3. Check any threshold computation for NaN sources (division by zero, undefined inputs)

Example fix

// before
agents: { myAgent: { scoring: { myScorer: { threshold: 70 } } } }
// after
agents: { myAgent: { scoring: { myScorer: { threshold: 0.7 } } } }

function assertThreshold(v: unknown, label: string, scorerId: string): asserts v is number {
  if (typeof v !== 'number' || !Number.isFinite(v) || v < 0 || v > 1) {
    throw new Error(`${label} threshold for "${scorerId}" must be a finite number in [0,1], got ${v}`);
  }
}

function isValidThreshold(v: unknown): v is number {
  return typeof v === 'number' && Number.isFinite(v) && v >= 0 && v <= 1;
}

try {
  validateThresholdConfig(scorerEntries);
} catch (e) {
  if (e instanceof MastraError && e.id === 'INVALID_SCORER_THRESHOLD') {
    logger.error('Bad scorer threshold in config', { detail: e.message });
  } else throw e;
}

When it happens

Trigger: Defining a scorer entry with `threshold: -0.1`, `threshold: 1.5`, `threshold: NaN`, `threshold: Infinity`, or a non-numeric value coerced into a number field, then validating the threshold config via validateThresholdConfig.

Common situations: Typo in the threshold value; computing a threshold with a formula that yields NaN (e.g. division by zero) or a percentage (0-100) instead of a fraction (0-1); loading thresholds from env/JSON with wrong units.

Related errors

• AGENT_INPUT_PROCESSOR_ERROR
• AGENT_INPUT_STEP_PROCESSOR_ERROR
• AGENT_GENEREATE_SCORER_NOT_FOUND
• MASTR_SCORER_FAILED_TO_CREATE_MISSING_ID
• MASTR_SCORER_FAILED_TO_RUN_MISSING_GENERATE_SCORE

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/ab858b186f7a5a2f. Report an issue: GitHub.