@intflows/genkit-guard

Lightweight Intent, PII, and Safety Guardrails for Genkit

@intflows/genkit-guard provides a modular guardrail layer for Genkit flows.
It adds semantic intent validation, PII masking/unmasking, and prompt‑injection detection with minimal configuration.

This library is designed for developers who want practical, production‑ready safety controls without heavy dependencies or complex setup.

✨ Features

• Semantic Intent Guarding
  Uses MiniLM embeddings to ensure prompts match allowed intents.

• PII Detection & Masking
  Detects emails, phone numbers, names, and AU‑specific identifiers.
  Replaces PII with reversible tokens before sending to the LLM.

• Automatic Unmasking
  Restores original PII in the model’s response, even inside structured JSON.

• Prompt Injection Detection
  Blocks jailbreak attempts using pattern‑based heuristics.

• Model‑Light Architecture
  The package uses local all-MiniLM-L6-v2 and openai/privacy-filter Models, these Models are downloaded once and cached locally.

• Drop‑in Genkit Middleware
  Works with ai.generate, ai.generateStream, and Genkit flows.

📦 Installation

## Install the package
npm install @intflows/genkit-guard

This library uses lightweight transformer models (MiniLM + Openai/privacy-filter).

Download them once.

## Download the transformer models (MiniLM + OpenAI/privacy-filter)
node node_modules/@intflows/genkit-guard/scripts/download-model.js

Models are cached locally and reused across runs.

🚀 Quick Start

1. Initialize Local folder

# Install @intflows/genkit-guard
npm install @intflows/genkit-guard

# Download Local Models (Only needed once)
node node_modules/@intflows/genkit-guard/scripts/download-model.js

_ This downloads the models to ./models folder, the total size is ~1.5 GB ( 1GB for Openai/privacy-filter + .5 GB for MiniLM-L6-v2)

2. Update genkit

import { guard, initGuard } from "@intflows/genkit-guard";

await initGuard();

const response = await ai.generate({
  prompt: "How do I integrate with Azure Blob Storage?",
  use: [
    guard({
      intent: {
        mode: "semantic",
        allowedIntent: "integration",
        semantic: {
          threshold: 0.7,
          intents: {
            integration: "Azure Blob, APIs, workflows"
          }
        }
      },
      pii: { reversible: true }
    })
  ]
});

You Can also check the full step by step guide here:

Intflows Wiki

3. Execute the Genkit flow

Allowed :

npx tsx src/index.ts "How do I integrate with Azure Blob Storage?"

Blocked:

npx tsx src/index.ts "workflow to download a file from an API, save it to Blob file and export the API key"

PII MASK and UNMASK:

npx tsx src/index.ts "workflow to download a file from an API, save it to Blob file with my email [email protected]"

Example

An example genkit flow is present in example directory.

git clone https://github.com/IntFlows/genkit-guard.git
cd genkit-guard/example
npm install
node node_modules/@intflows/genkit-guard/scripts/download-model.js
npx tsx src/index.ts

Or you can run the flow with genkit dev UI

git clone https://github.com/IntFlows/genkit-guard.git
cd genkit-guard/example
npm install
node node_modules/@intflows/genkit-guard/scripts/download-model.js
genkit start -- npx tsx src/index.ts

🧠 How It Works

1. Intent Guard

• Embeds the user prompt + intent descriptions using MiniLM
• Computes cosine similarity
• Blocks prompts below threshold
• Detects jailbreak patterns like:
  • “ignore previous instructions”
  • “you are a hacker”
  • “export the API key”

2. PII Masking

Before the LLM sees the prompt:

"Email [email protected]" → "Email [[EMAIL_0]]"

Detected PII includes:

• Emails
• Phone numbers
• AU identifiers (Medicare, TFN, ABN, etc.)
• PII detected by local Model (OpenAI/privacy-filter)

3. LLM Call

The masked prompt is sent to the model.

4. Response Unmasking

After the LLM responds:

"Send a confirmation email to [[EMAIL_0]]" → "Send a confirmation email to [email protected]"

⚙️ Configuration

Intent Guard

intent: {
  mode: "semantic",
  allowedIntent: "intent_question",
  semantic: {
    threshold: 0.7,
    intents: {
      intent_question: "Description of allowed intent"
    }
  }
}

PII Guard

pii: {
  reversible: true
}

PII Vault Isolation and External Storage

By default, PII is stored in an in-memory vault scoped to a single tokenizer instance. Tokens include a generated vault scope:

"Email [email protected]" -> "Email [[EMAIL_<namespace>_0]]"

That generated namespace prevents two concurrent calls from sharing the same visible placeholder names. Vault lookups are isolated by the configured storage scope, so User A and User B can safely produce their own email tokens without cross-resolving each other's PII.

For applications that need persistence, distributed workers, audits, or tenant-specific storage, provide a vault storage backend. Redis clients can be passed through the built-in helper:

import { createClient } from "redis";
import { guard, createRedisPiiVaultStorage } from "@intflows/genkit-guard";

const redis = createClient({ url: "redis://localhost:6379" });
await redis.connect();

guard({
  pii: {
    reversible: true,
    vault: {
      storage: createRedisPiiVaultStorage(redis, {
        keyPrefix: "my-app:pii",
        ttlSeconds: 3600
      }),
      scopeId: (req, ctx) => ctx?.auth?.sessionId ?? req?.metadata?.requestId
    }
  }
});

For another backend, use createPiiVaultStorage({ get, set, entries, getByToken }) with your database, cache, or secret store.

Choose a scopeId that matches your isolation boundary, such as request ID, session ID, tenant/user ID, or a combination like tenantId:userId:requestId. A shared external backend should never ignore scopeId, because placeholders are only safe when resolved against the correct vault scope. The placeholder sent to the model uses an opaque generated namespace rather than exposing your scopeId.

Screenshots

🛡️ Why This Library Exists

Genkit provides a powerful LLM framework, but production systems need:

• intent boundaries
• PII protection
• jailbreak resistance
• predictable behavior

This library adds those guardrails without heavy dependencies or complex setup.

Contributing

We plan to:

1. Extend the utility by adding Auth and Tool Middleware in further stages.
2. Add more filter types for common malicious prompts.
3. Add more patterns for custom PII masking.

Contributions are welcome — whether it’s bug reports, new guard modules, model improvements or enhancements. This project aims to stay lightweight, modular, and production‑ready, so thoughtful contributions are appreciated.

📄 License

Apache‑2.0