OpenSandbox MCP Sandbox Server

1. Overview

OpenSandbox MCP Server exposes the OpenSandbox Python SDK as MCP tools for Claude Code, Cursor, and other MCP-capable clients. It provides focused sandbox lifecycle management, command execution, and text file operations.

2. Installation & Startup

Source

uv sync
uv run opensandbox-mcp

Package

pip install opensandbox-mcp
opensandbox-mcp

Configuration

Environment variables:

• OPEN_SANDBOX_API_KEY
• OPEN_SANDBOX_DOMAIN

CLI overrides:

opensandbox-mcp --api-key ... --domain ... --protocol https

Config fields:

• api_key: OpenSandbox API key for authentication.
• domain: OpenSandbox API domain, for example api.opensandbox.io.
• protocol: http or https for API requests.
• request_timeout_seconds: HTTP request timeout in seconds.
• transport: stdio by default, or streamable-http.
• use-server-proxy: when present, forces the SDK client to use server proxy mode.

Streamable HTTP

opensandbox-mcp \
  --transport streamable-http \
  --host 0.0.0.0 \
  --port 8000

The HTTP transport defaults to 127.0.0.1:8000. Set --host 0.0.0.0 when the MCP server must be reached from another container, and use --port to select a different listening port. Keep the default loopback host unless the container network or an upstream gateway protects the exposed endpoint.

3. Integrations

Claude Code stdio

claude mcp add opensandbox-sandbox --transport stdio -- \
  opensandbox-mcp --api-key "$OPEN_SANDBOX_API_KEY" --domain "$OPEN_SANDBOX_DOMAIN"

Claude Code http

claude mcp add opensandbox-sandbox --transport http http://localhost:8000/mcp

Cursor stdio

{
  "mcpServers": {
    "opensandbox-sandbox": {
      "command": "opensandbox-mcp",
      "args": [
        "--api-key",
        "${OPEN_SANDBOX_API_KEY}",
        "--domain",
        "${OPEN_SANDBOX_DOMAIN}"
      ]
    }
  }
}

Cursor http

{
  "mcpServers": {
    "opensandbox-sandbox": {
      "url": "http://localhost:8000/mcp"
    }
  }
}

4. Tools

Notes:

• All tools operate on a sandbox_id returned by sandbox_create or sandbox_connect.
• file_read/file_write are text-only; use encoding and range_header for large files.

Sandbox

• sandbox_create: create a new sandbox and register it locally
• sandbox_connect: attach to an existing sandbox and register it locally
• sandbox_kill: terminate a sandbox by ID
• sandbox_get_info: fetch sandbox info by ID
• sandbox_list: list sandboxes with optional filter object
• sandbox_renew: extend sandbox expiration
• sandbox_healthcheck: check if sandbox is healthy
• sandbox_get_metrics: get resource metrics
• sandbox_get_endpoint: get network endpoint for a port

Command Execution

• command_run: run a command inside a sandbox
• command_interrupt: interrupt a running command

Filesystem

• file_read: read a text file
• file_write: write a text file
• file_delete: delete files
• file_search: search for files by glob
• file_create_directories: create directories
• file_delete_directories: delete directories
• file_move: move/rename files or directories
• file_replace_contents: replace file content

5. Minimal Workflow

1. sandbox_create -> keep the sandbox_id.
2. file_write code or assets into the sandbox.
3. command_run to execute, install dependencies, or start a service.
4. sandbox_get_endpoint if you expose a port.
5. sandbox_kill when finished.

6. Usage Examples

Here are some examples of what you can ask an LLM to do:

• "Create a Python sandbox and run a quick health command."
• "Write a Python script into the sandbox and run it."
• "Download a GitHub repo, install dependencies, and run its tests."
• "Generate a CSV file with fake sales data and run a simple summary script."
• "Start a tiny web server on port 8000 and return the public URL."
• "Build a minimal REST API (hello + health) and expose it on port 8000."
• "Create a tar.gz of /app and report the file size."
• "Build a simple Snake game and return the web endpoint where it can be accessed."