@aegis-sdk/sveltekit

SvelteKit handle hook for scanning LLM chat messages against prompt injection attacks.

Part of the Aegis.js prompt injection defense toolkit.

Installation

npm install @aegis-sdk/sveltekit @aegis-sdk/core

Quick Start

// src/hooks.server.ts
import { sequence } from '@sveltejs/kit/hooks';
import { aegisHandle } from '@aegis-sdk/sveltekit';

const aegis = aegisHandle({
  aegis: { policy: 'strict' },
  routes: ['/api/chat'],
});

export const handle = sequence(aegis);

Then access the scanned messages in your API route:

// src/routes/api/chat/+server.ts
import type { RequestHandler } from './$types';

export const POST: RequestHandler = async ({ locals }) => {
  const { messages, instance, auditLog } = locals.aegis;
  // messages are scanned and safe to forward to your LLM
  return new Response(JSON.stringify({ reply: '...' }));
};

API

aegisHandle(options?)

Creates a SvelteKit Handle function that scans incoming POST request bodies through aegis.guardInput() and attaches safe messages to event.locals.aegis. Returns 403 with violation details if input is blocked. Non-POST requests and routes not matching the filter are passed through without scanning.

Accepts either an AegisConfig directly or an AegisHandleOptions object:

| Option | Type | Default | Description | |---|---|---|---| | aegis | AegisConfig \| Aegis | {} | Aegis configuration or pre-constructed instance | | routes | (string \| RegExp)[] | -- | Routes to protect. If omitted, all POST requests are scanned | | messagesProperty | string | "messages" | Property on the request body to read messages from | | scanStrategy | ScanStrategy | "last-user" | Which messages to scan | | onBlocked | (event, error) => Response | -- | Custom error handler. Return a Response to take over |

aegisStreamTransform(configOrInstance?)

Returns a TransformStream<string, string> that monitors LLM output tokens for injection payloads, PII leaks, and canary token leaks.

// src/routes/api/chat/+server.ts
import { aegisStreamTransform } from '@aegis-sdk/sveltekit';

export const POST: RequestHandler = async ({ locals }) => {
  const transform = aegisStreamTransform(locals.aegis.instance);
  const monitoredStream = llmStream.pipeThrough(transform);
  return new Response(monitoredStream, {
    headers: { 'Content-Type': 'text/event-stream' },
  });
};

guardMessages(aegis, messages, options?)

Scans messages directly without using the handle hook. Useful in form actions, WebSocket handlers, or custom server routes. Throws AegisInputBlocked if input is blocked.

Re-exports

Aegis, AegisInputBlocked, AegisSessionQuarantined, AegisSessionTerminated, and all core types are re-exported for convenience.

Learn More

• Documentation
• GitHub

License

MIT