leap0.mdx

title	Leap0
sidebarTitle	Leap0
description	Use Leap0 sandbox backends with Deep Agents for isolated code execution with fast cold starts

Leap0 provides cloud sandboxes for AI agents: isolated compute, filesystem, and network boundaries, with sandboxes that start in about 200ms. See the Leap0 docs for signup, API keys, and platform details.

The LangChain integration is published as @leap0/langchain-leap0. It implements the Deep Agents sandbox backend and pairs with the leap0 TypeScript SDK.

Setup

```bash npm npm install @leap0/langchain-leap0 deepagents leap0 ```

```bash yarn
yarn add @leap0/langchain-leap0 deepagents leap0
```

```bash pnpm
pnpm add @leap0/langchain-leap0 deepagents leap0
```

@leap0/langchain-leap0 declares peer dependencies on deepagents and leap0; install them alongside the integration package as shown above.

Authentication

export LEAP0_API_KEY="your-key"

Create a sandbox backend

Create a sandbox with the Leap0 SDK, then connect it with Leap0Sandbox.fromConnected.

:::js

import { Leap0Client } from "leap0";
import { Leap0Sandbox } from "@leap0/langchain-leap0";

const client = new Leap0Client();
const sandbox = await client.sandboxes.create();
const backend = Leap0Sandbox.fromConnected(client, sandbox);

try {
  const result = await backend.execute("echo 'Hello from Leap0'");
  console.log(result.output);
} finally {
  try {
    await sandbox.delete();
  } finally {
    await client.close();
  }
}

:::

One-step create

To have the integration create a Leap0Client, provision a sandbox, and own teardown:

:::js

import { Leap0Sandbox } from "@leap0/langchain-leap0";

const backend = await Leap0Sandbox.create({
  leap0Config: {},
  createParams: { templateName: "base" },
});

try {
  const result = await backend.execute("echo hello");
  console.log(result.output);
} finally {
  await backend.close(); // deletes sandbox and closes the client
}

:::

Usage with Deep Agents

:::js

import { createDeepAgent } from "deepagents";
import { ChatAnthropic } from "@langchain/anthropic";
import { Leap0Sandbox } from "@leap0/langchain-leap0";
import { Leap0Client } from "leap0";

const client = new Leap0Client();
const sandbox = await client.sandboxes.create();
const backend = Leap0Sandbox.fromConnected(client, sandbox);

try {
  const agent = createDeepAgent({
    model: new ChatAnthropic({ model: "claude-sonnet-4-20250514" }),
    systemPrompt: "You are a coding assistant with sandbox access.",
    backend,
  });

  const result = await agent.invoke({
    messages: [
      { role: "user", content: "Create a hello world Python script and run it" },
    ],
  });
} finally {
  try {
    await sandbox.delete();
  } finally {
    await client.close();
  }
}

:::

Cleanup

You are responsible for managing the sandbox lifecycle via the Leap0 SDK unless you use Leap0Sandbox.create and backend.close() as above.

See also: Sandboxes.