Useful Cheatsheets
Build / AI / AI Development

Moderation & Output Guardrails

Implement content moderation, PII redaction, output schema guardrails, and refusal cascades for safe AI deployment.

TL;DR

  1. Screen inputs and outputs with moderations.create() before they reach users.
  2. Mask emails and phone numbers with maskPII() before prompting.
  3. Validate model output against a zod schema before delivery.
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OpenAI Moderation API

    Content Moderation Screen

    Detect hate, harassment, self-harm, and violence.

    import OpenAI from 'openai';
const client = new OpenAI();

async function isFlagged(
  input: string
): Promise<boolean> {
  const mod = await client.moderations.create({
    model: 'omni-moderation-latest',
    input,
  });
  return mod.results[0]?.flagged ?? false;
}
    Category Score Threshold Gate

    Flag inputs exceeding custom safety score thresholds.

    function checkHarassmentScore(
  result: any, maxScore = 0.5
) {
  const scores = result.category_scores;
  if (scores.harassment > maxScore) {
    const err = 'Input exceeds harassment threshold';
    throw new Error(err);
  }
}
    Dual Input-Output Moderation Gate

    Moderate both incoming user prompt and outgoing model reply.

    async function safeTurn(userInput: string) {
  if (await isFlagged(userInput)) {
    throw new Error('Unsafe user input');
  }
  const answer = await callLLM(userInput);
  if (await isFlagged(answer)) {
    throw new Error('Unsafe model answer');
  }
  return answer;
}

Personally Identifiable Information (PII) Redaction

    Regex Pattern PII Redactor

    Mask emails, phone numbers, and SSNs with placeholder tokens.

    function redactPII(text: string): string {
  const EMAIL_RE = /[^@\s]+@[^@\s]+\.[^@\s]+/g;
  const PHONE_RE = /\b\d{3}[-.]?\d{3}[-.]?\d{4}\b/g;
  return text
    .replace(EMAIL_RE, '[EMAIL]')
    .replace(PHONE_RE, '[PHONE]')
    .replace(/\b\d{3}-\d{2}-\d{4}\b/g, '[SSN]');
}
    Credit Card Luhn Algorithm Redactor

    Detect and mask valid credit card numbers in text strings.

    function redactCreditCards(text: string): string {
  const CARD_RE = /\b(?:\d[ -]*?){13,16}\b/g;
  return text.replace(CARD_RE, '[CARD]');
}
    PII Audit Logger

    Record redaction event without logging raw sensitive values.

    function logRedactionEvent(type: string) {
  securityMetrics.increment(
    'pii_redacted', 1, { type }
  );
}

Output Schema Guardrails with Zod

    Strict Output Schema Assertion

    Enforce domain constraints on generated JSON outputs.

    import { z } from 'zod';

const SafeOutputSchema = z.object({
  recommendation: z.string().max(200),
  riskLevel: z.enum(['low', 'medium', 'high']),
  confidence: z.number().min(0).max(1),
});

function validateOutput(rawJson: string) {
  return SafeOutputSchema.parse(JSON.parse(rawJson));
}
    HTML Injection Sanitizer

    Escape HTML tags to prevent cross-site scripting (XSS).

    function escapeHtml(str: string) {
  return str
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;');
}
    Schema Retry Fallback Handler

    Retry request with schema correction when output validation fails.

    async function getWithRetry(q: string, attempts = 2) {
  for (let i = 0; i < attempts; i++) {
    try {
      const raw = await callLLM(q);
      return validateOutput(raw);
    } catch (e) { /* retry */ }
  }
  throw new Error('Failed schema validation');
}

Refusal Cascades & Policy Management

    Graceful Refusal Formatter

    Deliver empathetic and helpful policy refusal messages.

    function formatRefusal(reason: string) {
  const msg = `Cannot assist with ${reason}.`;
  return {
    success: false,
    message: msg,
    alternative: 'Can help with general info.',
  };
}
    Topic Blocklist Guard

    Intercept forbidden operational topics before LLM dispatch.

    const BANNED_TOPICS = [
  'medical_advice', 'crypto_speculation',
];
function checkTopic(topic: string) {
  if (BANNED_TOPICS.includes(topic)) {
    return formatRefusal(topic);
  }
}
    Safety Telemetry Incident Hook

    Log safety violation events for compliance audits.

    function recordSafetyViolation(
  cat: string, usr: string
) {
  complianceLogger.warn('policy_violation', {
    category: cat,
    userId: usr,
    timestamp: new Date().toISOString(),
  });
}

Tips

  1. Execute omni-moderation-latest checks asynchronously on streaming tokens to catch safety violations without inflating initial Time-to-First-Token latency.
  2. Mask credit cards and Social Security numbers using client-side regex filters prior to transmitting prompts across provider network boundaries.

Warnings

  1. Never display unvalidated LLM output containing user-generated HTML directly in browsers without strict HTML escaping.
  2. Avoid hardcoded naive keyword blocklists that produce frequent false positive refusals on legitimate medical or technical inquiries.

In Practice

FAQ