E2b Sandbox

npm version license

An MCP (Model Context Protocol) server that connects Claude Code with E2B cloud sandboxes, giving you isolated Linux VMs to work on any GitHub repository without touching your local machine.

What It Does

This server provides Claude Code with 29 tools to create cloud sandboxes, clone repos, run commands, manage files, and perform git operations — all in a secure, disposable Linux environment.

Your local machine stays untouched. Every operation happens inside an E2B sandbox VM.

Token Savings

Running commands through E2B sandboxes instead of local Bash reduces the tokens consumed per conversation. Tool outputs are structured and truncated (100KB per stream, 200KB total), so large build/test outputs don't flood your context window.

Why it scales: A local npm install on a monorepo can dump 10K+ lines into context. A full test suite adds thousands more. With E2B, those outputs are capped and structured. Background processes (sandbox_exec_background) return only a process ID — zero streaming output. Directory listings are capped at 1000 entries. The result: your context window stays available for actual work instead of being consumed by terminal noise.

Use Cases

Work on Any GitHub Repo Remotely

Clone any repository into a sandbox, run its build and test suite, make changes, and push — without ever installing the project locally.

You: "Clone github.com/fastify/fastify, run the tests, and find why test X fails"

Claude Code:
  → sandbox_create
  → sandbox_git_clone "https://github.com/fastify/fastify"
  → sandbox_exec "npm install"
  → sandbox_exec "npm test"
  → sandbox_file_read (inspect failing test)
  → sandbox_file_write (apply fix)
  → sandbox_exec "npm test" (verify)

Safe Experimentation

Try risky changes — dependency upgrades, major refactors, migration scripts — in a throwaway environment. If it breaks, sandbox_kill and start fresh.

Persistent Development Sessions

Pause a sandbox when you're done for the day, resume it tomorrow with all your files and state intact. No more rebuilding environments from scratch.

You: "Pause this sandbox, I'll continue tomorrow"

Claude Code:
  → sandbox_pause (saves state)

Next day:
  → sandbox_resume (picks up where you left off)

Preview Dev Servers

Start a web app in a sandbox and get a public URL to preview it in your browser — no port forwarding or tunneling needed.

You: "Start the dev server and give me a URL to preview it"

Claude Code:
  → sandbox_exec_background "npm run dev"
  → sandbox_get_url 3000
  → Returns: https://abc123-3000.e2b.dev

Multi-Repo Parallel Work

Spin up multiple sandboxes, clone different repos, work on all of them simultaneously. Each sandbox is fully isolated.

Clean CI-Like Testing

Run your full test suite in a fresh Linux environment. Catch "works on my machine" issues before pushing to CI.

Open Source Contributions

Fork a repo, clone it in a sandbox, make your changes, commit, and push to your fork — all without local project setup.

Code Review in a Live Environment

Clone a PR branch into a sandbox, run the tests, inspect the changes, and verify the behavior — without checking out the branch locally.

Getting Started

Prerequisites

• Node.js >= 18
• Claude Code CLI installed
• E2B API key (free tier available)
• GitHub Personal Access Token (optional, for private repos and push)

1. Register with Claude Code

No separate install needed — just point Claude Code at the npm package with npx:

claude mcp add e2b-sandbox -s user \
  -e E2B_API_KEY=your-e2b-api-key \
  -e GITHUB_TOKEN=your-github-token \
  -- npx -y e2b-sandbox-mcp

Restart Claude Code after adding the server.

npm install -g e2b-sandbox-mcp

claude mcp add e2b-sandbox -s user \
  -e E2B_API_KEY=your-e2b-api-key \
  -e GITHUB_TOKEN=your-github-token \
  -- e2b-sandbox-mcp

2. Use It

Start Claude Code and ask it to work on any repo:

"Create a sandbox, clone https://github.com/expressjs/express, and run the test suite"

Claude Code will call the MCP tools automatically.

Available Tools

Sandbox Lifecycle

Networking & File Transfer

Command Execution

File Operations

Git Operations

Environment Variables

Architecture

src/
├── index.ts                  # MCP server entry point (stdio transport)
├── types.ts                  # Shared types and error helpers
├── services/
│   └── sandbox-manager.ts    # Sandbox registry (tracks active VMs)
└── tools/
    ├── sandbox.ts            # Lifecycle tools
    ├── commands.ts           # Command execution tools
    ├── filesystem.ts         # File operation tools
    └── git.ts                # Git operation tools

The server manages a registry of active sandbox instances. Each tool references sandboxes by ID, allowing concurrent work across multiple isolated environments.

Important Notes

• Sandboxes are real VMs. Commands execute on actual Linux machines in E2B's cloud.
• Git push is real. Pushing from a sandbox pushes to the actual remote repository.
• Sandboxes auto-expire. Default timeout is 5 minutes. Use sandbox_keep_alive to extend.
• E2B usage has costs. Check E2B pricing for details. Free tier is available.
• Sandboxes are isolated from your machine, but not from the internet. Network requests, git pushes, and npm publishes are real.

License

MIT