techlibs/codesandbox-mcp

CodeSandbox MCP Server

A Model Context Protocol (MCP) server that exposes CodeSandbox SDK operations as tools for AI agents.

• Runtime: Node.js 18+
• Auth: CODESANDBOX_API_TOKEN (or CSB_API_KEY)
• SDK: Official @codesandbox/sdk

Install / Run

Use via npx in your MCP client config.

Example (Cursor/Claude Desktop mcp.json snippet):

{
  "mcpServers": {
    "codesandbox": {
      "command": "npx",
      "args": [
        "-y",
        "@techlibs/codesandbox-mcp@latest",
        "--read-only"
      ],
      "env": {
        "CODESANDBOX_API_TOKEN": "<your-api-token>"
      }
    }
  }
}

CLI binary name: mcp-server-codesandbox

You can also run directly:

npx -y @techlibs/codesandbox-mcp@latest --help

Flags:

• --read-only: disallow mutating tools (write/rename) and default sessions to read permission
• --vm-tier <tier>: default VM tier when creating/resuming
• --hibernation-timeout <seconds>: default inactivity hibernation timeout
• --keep-alive: keep sessions active while connected
• --log-level <error|warn|info|debug>

Tools (Stateless)

All tools are stateless: no server-managed session registry. Each call performs the SDK operation directly using only the provided arguments.

• createSandbox

  • Description: Create a sandbox (optionally from template id) and optionally start with custom VM settings.
  • Params:
    • privacy (public|private): Privacy of the sandbox.
    • title (string): Optional title.
    • description (string): Optional description.
    • tags (string[]): Up to 10 tags.
    • path (string): Destination folder path inside your workspace.
    • id (string): Template sandbox ID to fork from.
    • ipcountry (string): ISO 3166-1 alpha-2 country hint for VM scheduling.
    • vmTier (string): VM tier (e.g. Pico, Nano, ...). Overrides server default.
    • hibernationTimeoutSeconds (number): Inactivity timeout before VM hibernates.
    • automaticWakeupConfig.http (boolean): Auto-wake on HTTP.
    • automaticWakeupConfig.websocket (boolean): Auto-wake on WebSocket.

• resumeSandbox

  • Description: Resume (or start) a sandbox VM.
  • Params:
    • sandboxId (string): Target sandbox ID.

• hibernateSandbox

  • Description: Hibernate a sandbox VM (saves and sleeps the VM).
  • Params:
    • sandboxId (string): Target sandbox ID.

• getSandboxInfo

  • Description: Get sandbox metadata without starting the VM.
  • Params:
    • sandboxId (string): Sandbox ID to fetch.

• updateSandbox

  • Description: Update VM settings for a running sandbox.
  • Params:
    • sandboxId (string): Target sandbox ID.
    • vmTier (string): Change VM tier (Pico|Nano|Micro|Small|Medium|Large|XLarge).
    • hibernationTimeoutSeconds (number): Update inactivity hibernation timeout.

• createSession

  • Description: Create a session for a sandbox (no state is stored server-side).
  • Params:
    • sandboxId (string): Target sandbox ID.
    • sessionId (string, optional): Provide a specific session ID; if omitted a UUID is generated.
    • permission (read|write): Session permission. Use read for safe, non-mutating access.
    • env (Record<string,string>, optional): Environment variables for the session.
    • git (object, optional): Git identity/options for the session creation.
      • provider (string): e.g. "github".
      • username (string, optional)
      • accessToken (string, optional)
      • email (string)
      • name (string, optional)

• resumeSession

  • Description: Connect to an existing session by sandboxId + sessionId. If the session does not exist, it will be created using the optional parameters.
  • Params:
    • sandboxId (string): Target sandbox ID.
    • sessionId (string): Session identifier to connect to.
    • permission (read|write, optional): Used if creating the session.
    • env (Record<string,string>, optional): Used if creating the session.

• readFile

  • Description: Read a file from the sandbox filesystem. The tool connects per call using sandboxId + sessionId.
  • Params:
    • sandboxId (string): Target sandbox ID.
    • sessionId (string): Session identifier (created if missing as needed).
    • permission (read|write, optional): Used if creating the session.
    • env (Record<string,string>, optional): Used if creating the session.
    • path (string): Absolute path inside the sandbox filesystem.
    • encoding (utf8|base64, optional): Encoding for the returned content (default utf8).

• readdir

  • Description: List files and directories at a given path. The tool connects per call using sandboxId + sessionId.
  • Params:
    • sandboxId (string): Target sandbox ID.
    • sessionId (string): Session identifier (created if missing as needed).
    • permission (read|write, optional): Used if creating the session (defaults to read in read-only mode).
    • env (Record<string,string>, optional): Used if creating the session.
    • path (string): Absolute path to list within the sandbox filesystem.

• writeFile

  • Description: Write a file in the sandbox filesystem. The tool connects per call using sandboxId + sessionId.
  • Params:
    • sandboxId (string): Target sandbox ID.
    • sessionId (string): Session identifier (created if missing as needed). Must allow write.
    • permission (read|write, optional): Used if creating the session (typically write).
    • env (Record<string,string>, optional): Used if creating the session.
    • path (string): Absolute path to the file.
    • content (string): Content to write (encoded per encoding).
    • encoding (utf8|base64, optional): Content encoding (default utf8).
    • overwrite (boolean, optional): Overwrite existing file (default true).
    • create (boolean, optional): Create the file if missing (default true).

• rename

  • Description: Rename/move a file or directory. The tool connects per call using sandboxId + sessionId.
  • Params:
    • sandboxId (string): Target sandbox ID.
    • sessionId (string): Session identifier (created if missing as needed). Must allow write.
    • permission (read|write, optional): Used if creating the session (typically write).
    • env (Record<string,string>, optional): Used if creating the session.
    • from (string): Source path.
    • to (string): Destination path.
    • overwrite (boolean, optional): Overwrite if destination exists (default true).

Notes:

• Filesystem operations connect a SandboxClient for the duration of the call and dispose it immediately; no state is retained.
• Outputs are returned as text blocks (JSON payloads serialized to string) for broad client compatibility.

Development

• Build: npm run build
• Dev (stdio): npm run dev (requires token env var)

Environment

• CODESANDBOX_API_TOKEN (preferred) or CSB_API_KEY: PAT with scopes for Sandbox Creation, Read/Edit, VM Manage, Preview Token Manage.

Limitations

• This server targets CodeSandbox sandboxes (VMs), not legacy projects.
• Session resume uses sandbox.connect({ id: sessionId }).