@edwinfom/ai-guard

A security middleware for AI API responses — PII redaction, schema enforcement, prompt injection detection, budget sentinel, and more.

The Problem

When integrating AI APIs (OpenAI, Anthropic, Gemini) into production applications, developers face recurring pain points with no standardized solution:

• Malformed JSON — LLMs sometimes wrap responses in markdown fences or add explanatory text, crashing your pipeline.
• PII leakage — Users send passwords or card numbers in prompts. AI responses can echo back sensitive data from your RAG database.
• Prompt injection — Malicious users try to override your system prompt with "Ignore all previous instructions…"
• System prompt theft — An attacker tricks the AI into repeating your confidential instructions.
• Toxic or harmful content — No built-in content moderation between the LLM and your users.
• Hallucinations in RAG — The AI invents facts not present in your source documents.
• Surprise billing — Token usage spikes without any warning or hard limit.
• Abuse — A single user floods your endpoint with requests.

@edwinfom/ai-guard acts as a security membrane between your application and any AI provider. One wrapper, all protections.

import { Guardian } from '@edwinfom/ai-guard';
import { z } from 'zod';
 
const guard = new Guardian({
  pii:          { onInput: true, onOutput: true },
  schema:       { validator: z.object({ city: z.string(), temp: z.number() }), repair: 'retry' },
  injection:    { enabled: true, sensitivity: 'medium' },
  content:      { enabled: true, sensitivity: 'medium' },
  canary:       { enabled: true },
  hallucination:{ sources: [ragDocument1, ragDocument2] },
  budget:       { maxTokens: 2000, maxCostUSD: 0.05, model: 'gpt-4o-mini' },
  rateLimit:    { maxRequests: 10, windowMs: 60_000, keyFn: (p) => getUserId(p) },
  onAudit:      (entry) => logger.info(entry),
});
 
const result = await guard.protect(
  (safePrompt) => openai.chat.completions.create({ model: 'gpt-4o-mini', messages: [{ role: 'user', content: safePrompt }] }),
  userPrompt
);
 
console.log(result.data);              // typed by your Zod schema
console.log(result.meta.budget);       // { totalTokens: 312, estimatedCostUSD: 0.000047 }
console.log(result.meta.piiRedacted);  // [{ type: 'email', value: 'user@...', ... }]
console.log(result.meta.canaryLeaked); // false — system prompt was not leaked

Features

What makes @edwinfom/ai-guard different?

Most teams bolt security on after the fact — rate limiting in nginx, PII scrubbing in a post-processing step, schema validation inline. @edwinfom/ai-guard is the first JavaScript library that puts all AI-specific security concerns in one composable, typed wrapper.