Vercel AI SDK

Prerequisites

Install and initialize the TypeScript SDK. The example uses that client as fw.

Wrap your model

Install compatible AI SDK and OpenAI provider packages. Set OPENAI_API_KEY in your service environment for the model provider.

npm install ai@^6 @ai-sdk/openai@^3

Use middleware to check input, then classify the generated text before returning it. This example enforces both checks.

import { FirewallBlockedException, HookLabel } from "@silmaril-security/sdk"
import { wrapLanguageModel, generateText } from "ai"
import { openai } from "@ai-sdk/openai"

const model = wrapLanguageModel({
  model: openai("gpt-5.4"),
  middleware: fw.asMiddleware({ shadowMode: false, scanOutput: false }),
})

const response = await generateText({
  model,
  prompt: "Summarize the benefits of request validation.",
})

const result = await fw.classify(response.text, { hook: HookLabel.LLM_OUTPUT })
const blocked =
  result.prediction === "MALICIOUS" || result.governance?.action === "block"

if (blocked) {
  throw new FirewallBlockedException({
    score: result.score,
    threshold: result.threshold,
    promptText: response.text,
    hook: HookLabel.LLM_OUTPUT,
    result,
  })
}

console.log(response.text)

Expected result

Allowed input reaches the model, and allowed output is returned only after classification. A blocked input or output throws FirewallBlockedException. Handle it at your application boundary and return a safe response. Let API and network failures follow your error policy. See TypeScript errors.

Coverage

The middleware checks the latest user message or tool responses before each model call. With AI SDK 6, use the explicit output check above instead of relying on the middleware’s scanOutput option. This example protects generated text. Classify tool-call arguments before executing a tool. Streaming output must be buffered and classified before delivery if you need to prevent blocked content from reaching the caller. Every protected call must use the wrapped model. For models routed through Vercel AI Gateway, use the gateway guide. Vercel AI SDK documentation

Start

Concepts

SDKs

AI gateways

Integrations

Deployment

MacOS

Prerequisites

Wrap your model

Expected result

Coverage

​Prerequisites

​Wrap your model

​Expected result

​Coverage

Prerequisites

Wrap your model

Expected result

Coverage