AI SDK - Vercel Sandbox

This package is experimental.

HarnessV1SandboxProvider implementation for Vercel Sandbox.

Setup

npm i @ai-sdk/sandbox-vercel

Usage

The factory is synchronous. The returned provider is stable; the actual @vercel/sandbox Sandbox is created on demand inside provider.createSession().

import { createVercelSandbox } from '@ai-sdk/sandbox-vercel';

const vercelSandbox = createVercelSandbox({
  runtime: 'node24',
  ports: [3000],
});

const networkSandboxSession = await vercelSandbox.createSession();
const sandboxSession = networkSandboxSession.restricted();

await sandboxSession.writeTextFile({ path: 'hello.txt', content: 'hi' });

const { stdout } = await sandboxSession.run({
  command: 'cat hello.txt',
});
console.log(stdout); // "hi"
await networkSandboxSession.stop();

networkSandboxSession.restricted() is typed as Experimental_SandboxSession, so it's safe to pass to AI SDK tools that accept experimental_sandbox. The network sandbox session itself carries the infra surface (ports, getPortUrl, setNetworkPolicy, stop) that only the harness should reach for.

The flat-field settings are aliased directly from @vercel/sandbox's Sandbox.create parameters, so every option Vercel supports — including its native NetworkPolicy — is available without re-declaration:

const sandbox = createVercelSandbox({
  runtime: 'node24',
  ports: [3000],
  timeout: 10 * 60 * 1000,
  networkPolicy: {
    allow: ['api.example.com'],
    subnets: { deny: ['169.254.169.254/32'] },
  },
});

To wrap an already-created @vercel/sandbox Sandbox instead — e.g. when you need credentials or options outside the factory's settings, or you want to share one sandbox across multiple harness sessions — pass it via sandbox. Install @vercel/sandbox directly if your application imports Sandbox. The network sandbox session's stop() is a no-op in this case; the caller owns the lifecycle.

import { createVercelSandbox } from '@ai-sdk/sandbox-vercel';
import { Sandbox } from '@vercel/sandbox';

const sandbox = createVercelSandbox({
  sandbox: await Sandbox.create({ runtime: 'node24', ports: [3000] }),
});

Mid-session network policy

Once the network sandbox session is alive, the host can update outbound network policy on the running sandbox:

await networkSandboxSession.setNetworkPolicy?.({
  mode: 'custom',
  allowedHosts: ['api.example.com'],
  deniedCIDRs: ['169.254.169.254/32'],
});

HarnessV1NetworkPolicy is the harness-level abstraction used here. The provider translates it to @vercel/sandbox's native NetworkPolicy for enforcement.