How to integrate E2b MCP with Mastra AI

This guide walks you through connecting E2b to Mastra AI using the Composio tool router. By the end, you'll have a working E2b agent that can run a python script to analyze csv data, execute javascript code to validate user input, start a sandbox and list installed packages through natural language commands. This guide will help you understand how to give your Mastra AI agent real control over a E2b account through Composio's E2b MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

E2b logoE2b
Api Key

E2b is an open-source platform for running code in secure, sandboxed environments. It enables safe multi-language code execution for AI-powered apps.

27 Tools

Introduction

This guide walks you through connecting E2b to Mastra AI using the Composio tool router. By the end, you'll have a working E2b agent that can run a python script to analyze csv data, execute javascript code to validate user input, start a sandbox and list installed packages through natural language commands.

This guide will help you understand how to give your Mastra AI agent real control over a E2b account through Composio's E2b MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

Also integrate E2b with

TL;DR

Here's what you'll learn:
  • Set up your environment so Mastra, OpenAI, and Composio work together
  • Create a Tool Router session in Composio that exposes E2b tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch E2b tool definitions and attach them as a toolset
  • Build a Mastra agent that can reason, call tools, and return structured results
  • Run an interactive CLI where you can chat with your E2b agent

What is Mastra AI?

Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP.

Key features include:

  • MCP Client: Built-in support for Model Context Protocol servers
  • Toolsets: Organize tools into logical groups
  • Step Callbacks: Monitor and debug agent execution
  • OpenAI Integration: Works with OpenAI models via @ai-sdk/openai

What is the E2b MCP server, and what's possible with it?

The E2b MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your E2b account. It provides structured and secure access so your agent can perform E2b operations on your behalf.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Step by step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • Node.js 18 or higher
  • A Composio account with an active API key
  • An OpenAI API key
  • Basic familiarity with TypeScript
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key.
  • You need credits or a connected billing setup to use the models.
  • Store the key somewhere safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Go to Settings and copy your API key.
  • This key lets your Mastra agent talk to Composio and reach E2b through MCP.
3

Install dependencies

bash
npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv

Install the required packages.

What's happening:

  • @composio/core is the Composio SDK for creating MCP sessions
  • @mastra/core provides the Agent class
  • @mastra/mcp is Mastra's MCP client
  • @ai-sdk/openai is the model wrapper for OpenAI
  • dotenv loads environment variables from .env
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your requests to Composio
  • COMPOSIO_USER_ID tells Composio which user this session belongs to
  • OPENAI_API_KEY lets the Mastra agent call OpenAI models
5

Import libraries and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey as string,
});
What's happening:
  • dotenv/config auto loads your .env so process.env.* is available
  • openai gives you a Mastra compatible model wrapper
  • Agent is the Mastra agent that will call tools and produce answers
  • MCPClient connects Mastra to your Composio MCP server
  • Composio is used to create a Tool Router session
6

Create a Tool Router session for E2b

typescript
async function main() {
  const session = await composio.create(
    composioUserID as string,
    {
      toolkits: ["e2b"],
    },
  );

  const composioMCPUrl = session.mcp.url;
  console.log("E2b MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "e2b" for E2b access
  • session.mcp.url is the MCP URL that Mastra's MCPClient will connect to
7

Configure Mastra MCP client and fetch tools

typescript
const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      nasdaq: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

console.log("Fetching MCP tools from Composio...");
const composioTools = await mcpClient.getTools();
console.log("Number of tools:", Object.keys(composioTools).length);
What's happening:
  • MCPClient takes an id for this client and a list of MCP servers
  • The headers property includes the x-api-key for authentication
  • getTools fetches the tool definitions exposed by the E2b toolkit
8

Create the Mastra agent

typescript
const agent = new Agent({
    name: "e2b-mastra-agent",
    instructions: "You are an AI agent with E2b tools via Composio.",
    model: "openai/gpt-5",
  });
What's happening:
  • Agent is the core Mastra agent
  • name is just an identifier for logging and debugging
  • instructions guide the agent to use tools instead of only answering in natural language
  • model uses openai("gpt-5") to configure the underlying LLM
9

Set up interactive chat interface

typescript
let messages: AiMessageType[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end.\n");

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: "> ",
});

rl.prompt();

rl.on("line", async (userInput: string) => {
  const trimmedInput = userInput.trim();

  if (["exit", "quit", "bye"].includes(trimmedInput.toLowerCase())) {
    console.log("\nGoodbye!");
    rl.close();
    process.exit(0);
  }

  if (!trimmedInput) {
    rl.prompt();
    return;
  }

  messages.push({
    id: crypto.randomUUID(),
    role: "user",
    content: trimmedInput,
  });

  console.log("\nAgent is thinking...\n");

  try {
    const response = await agent.generate(messages, {
      toolsets: {
        e2b: composioTools,
      },
      maxSteps: 8,
    });

    const { text } = response;

    if (text && text.trim().length > 0) {
      console.log(`Agent: ${text}\n`);
        messages.push({
          id: crypto.randomUUID(),
          role: "assistant",
          content: text,
        });
      }
    } catch (error) {
      console.error("\nError:", error);
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    console.log("\nSession ended.");
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • messages keeps the full conversation history in Mastra's expected format
  • agent.generate runs the agent with conversation history and E2b toolsets
  • maxSteps limits how many tool calls the agent can take in a single run
  • onStepFinish is a hook that prints intermediate steps for debugging

Complete Code

Here's the complete code to get you started with E2b and Mastra AI:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({ apiKey: composioAPIKey as string });

async function main() {
  const session = await composio.create(composioUserID as string, {
    toolkits: ["e2b"],
  });

  const composioMCPUrl = session.mcp.url;

  const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      e2b: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "e2b-mastra-agent",
    instructions: "You are an AI agent with E2b tools via Composio.",
    model: "openai/gpt-5",
  });

  let messages: AiMessageType[] = [];

  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: "> ",
  });

  rl.prompt();

  rl.on("line", async (input: string) => {
    const trimmed = input.trim();
    if (["exit", "quit"].includes(trimmed.toLowerCase())) {
      rl.close();
      return;
    }

    messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed });

    const { text } = await agent.generate(messages, {
      toolsets: { e2b: composioTools },
      maxSteps: 8,
    });

    if (text) {
      console.log(`Agent: ${text}\n`);
      messages.push({ id: crypto.randomUUID(), role: "assistant", content: text });
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main();

Conclusion

You've built a Mastra AI agent that can interact with E2b through Composio's Tool Router. You can extend this further by:
  • Adding other toolkits like Gmail, Slack, or GitHub
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows
TOOLS

Supported Tools

Every E2b action and event your agent gets out of the box.

Connect to Sandbox

Tool to connect to an existing E2B sandbox and retrieve its details.

Create Template

Tool to create a new E2B template with specified configuration.

Create Webhook

Tool to register a new webhook to receive sandbox lifecycle events for the team.

Delete Sandbox

Tool to terminate and permanently delete a running E2B sandbox instance.

Delete Webhook

Tool to unregister a webhook and stop receiving lifecycle events.

Check API Health

Tool to check the health status of the E2B API.

Get Sandbox

Tool to retrieve detailed information about a specific sandbox by its ID.

Get Sandbox Logs

Tool to retrieve logs from a specific E2B sandbox instance.

Get Sandbox Lifecycle Events

Tool to retrieve the latest lifecycle events for a particular sandbox instance.

Get Sandbox Metrics

Tool to retrieve timestamped CPU, memory, and disk usage metrics for a sandbox.

Get Team Metrics

Tool to retrieve timestamped CPU, memory, and disk usage metrics for a team.

Get Team Maximum Metrics

Tool to retrieve the maximum value for a specific team metric in a given interval.

Get Template Build Status

Tool to get the status of a template build.

Get Template Files

Tool to get an upload link for a tar file containing build layer files.

Get Webhook Configuration

Tool to retrieve the current webhook configuration for a specific webhook.

List All Sandboxes

Tool to list all running and paused sandboxes associated with your team.

List Sandboxes Metrics

Tool to retrieve timestamped CPU, memory, and disk usage metrics for multiple sandboxes.

List Team Sandbox Lifecycle Events

Tool to retrieve the latest lifecycle events across all sandboxes associated with the team.

List All Templates

Tool to list all available E2B templates for your team.

List All Webhooks

Tool to retrieve all registered webhooks for your team.

Pause Sandbox

Tool to pause a running E2B sandbox preserving its filesystem and memory state.

Create Sandbox

Tool to create a new E2B sandbox from a template.

Set Sandbox Timeout

Tool to set the timeout for an E2B sandbox.

Refresh Sandbox

Tool to refresh an E2B sandbox and extend its time to live.

Start Template Build

Tool to start a build for an E2B template.

Update Template

Tool to update an E2B template configuration.

Update Webhook Configuration

Tool to update an existing webhook configuration including URL, enabled status, and subscribed events.

FAQ

Frequently asked questions

With a standalone E2b MCP server, the agents and LLMs can only access a fixed set of E2b tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from E2b and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Mastra AI fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right E2b tools.

Yes, absolutely. You can configure which E2b scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your E2b data and credentials are handled as safely as possible.

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