Deno

Use Deno sandbox backends with deepagents for isolated code execution in Linux microVMs

Deno Deploy provides Linux microVMs for isolated code execution. Best for Deno and JavaScript workloads.

Setup

npm

npm install @langchain/deno

Authentication

Get your token from app.deno.com → Settings → Organization Tokens.

export DENO_DEPLOY_TOKEN=your_token

Or pass credentials directly:

const sandbox = await DenoSandbox.create({
  auth: { token: "your-token-here" },
});

Usage with deepagents

import { createDeepAgent } from "deepagents";
import { ChatAnthropic } from "@langchain/anthropic";
import { DenoSandbox } from "@langchain/deno";

const sandbox = await DenoSandbox.create({
  memoryMb: 1024,
  lifetime: "10m",
});

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

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

Standalone usage

import { DenoSandbox } from "@langchain/deno";

const sandbox = await DenoSandbox.create({
  memoryMb: 1024,
  lifetime: "10m",
});

const result = await sandbox.execute("deno --version");
console.log(result.output);

await sandbox.close();

Configuration

Option	Type	Default	Description
memoryMb	number	768	Memory in MB (768-4096)
lifetime	"session" | string	"session"	Lifetime ("session", "5m", "30s")
region	string	-	Region. Options: "ams" | "ord"

Available regions

Region Code	Location
ams	Amsterdam
ord	Chicago

Lifetime options

• "session" (default): Sandbox shuts down when you close/dispose the client
• Duration string: Keep sandbox alive for a specific time (e.g., "5m", "30s")

Accessing the Deno SDK

For advanced features, access the underlying Deno SDK:

const denoSandbox = await DenoSandbox.create();
const sdk = denoSandbox.sandbox;

// Expose HTTP port
const url = await sdk.exposeHttp({ port: 3000 });

// Expose SSH
const ssh = await sdk.exposeSsh();

// Evaluate JavaScript
const result = await sdk.eval("1 + 2");

// Set environment variables
await sdk.env.set("API_KEY", "secret");

// Shell template literals
const output = await sdk.sh`echo "Hello from Deno!"`.text();

// Start a JavaScript runtime
const runtime = await sdk.createJsRuntime({ entrypoint: "server.ts" });

Reconnecting to existing sandboxes

Reconnecting requires a duration-based lifetime (not "session"):

// Create with duration lifetime
const sandbox = await DenoSandbox.create({
  memoryMb: 1024,
  lifetime: "30m",
});
const sandboxId = sandbox.id;
await sandbox.close(); // Close connection, sandbox keeps running

// Later: reconnect
const reconnected = await DenoSandbox.connect(sandboxId);
const result = await reconnected.execute("ls -la");

Factory functions

import { createDenoSandboxFactory, createDenoSandboxFactoryFromSandbox } from "@langchain/deno";

// Create new sandbox per invocation
const factory = createDenoSandboxFactory({ memoryMb: 1024 });

// Or reuse an existing sandbox across invocations
const sandbox = await DenoSandbox.create();
const reuseFactory = createDenoSandboxFactoryFromSandbox(sandbox);

Error handling

import { DenoSandboxError } from "@langchain/deno";

try {
  await sandbox.execute("some command");
} catch (error) {
  if (error instanceof DenoSandboxError) {
    switch (error.code) {
      case "NOT_INITIALIZED":
        await sandbox.initialize();
        break;
      case "COMMAND_TIMEOUT":
        console.error("Command took too long");
        break;
      case "AUTHENTICATION_FAILED":
        console.error("Check your Deno Deploy token");
        break;
    }
  }
}

Error codes

Code	Description
NOT_INITIALIZED	Sandbox not initialized - call initialize()
ALREADY_INITIALIZED	Cannot initialize twice
AUTHENTICATION_FAILED	Invalid or missing Deno Deploy token
SANDBOX_CREATION_FAILED	Failed to create sandbox
SANDBOX_NOT_FOUND	Sandbox ID not found or expired
COMMAND_TIMEOUT	Command execution timed out
COMMAND_FAILED	Command execution failed
FILE_OPERATION_FAILED	File read/write failed
RESOURCE_LIMIT_EXCEEDED	CPU, memory, or storage limits exceeded

Limits and constraints

Constraint	Value
Minimum memory	768 MB
Maximum memory	4096 MB (4 GB)
Disk space	10 GB
vCPUs	2
Working directory	/home/app
Network access	Full (by default)

Environment variables

Variable	Description
DENO_DEPLOY_TOKEN	Deno Deploy organization access token

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