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Runno MCP Server

Provides an MCP server to run code using the Runno sandbox and WASI in a controlled environment.

Installation

Add the following to your MCP client configuration file.

Configuration

{
  "mcpServers": {
    "taybenlor-runno": {
      "command": "npx",
      "args": [
        "@runno/mcp"
      ]
    }
  }
}

The Runno MCP Server provides a lightweight, configurable endpoint to execute code snippets inside a secure WASI-based sandbox using Runno’s sandbox. It enables you to run multiple runtimes and sandboxed code through a simple MCP interface, making it practical to manage and scale code execution in controlled environments.

How to use

You connect to and run the Runno MCP Server by configuring an MCP client to launch the server process as described in the configuration example. The server is designed to run locally as a standalone process that serves code execution through the MCP protocol, allowing your client to request code execution across supported runtimes.

How to install

Prerequisites: you need a working Node.js and npm installation. Ensure Node.js is installed on your system before proceeding.

{
  "mcpServers": {
    "runno": {
      "command": "npx",
      "args": ["@runno/mcp"]
    }
  }
}

Getting started commands

To start the Runno MCP Server locally, run the exact command implied by the configuration snippet.

npx @runno/mcp

Start in your MCP client

Within your MCP client configuration, reference the provided server entry. The example shows the server being invoked via npx with the Runno MCP package, so your client can initiate or connect to this server using the same command pattern.

Additional notes

Keep in mind the Runno MCP Server uses WebAssembly and sandboxed runtimes to execute code. You will manage runtimes and code execution through the MCP interface, enabling isolation and reproducibility for running examples or tests.

Configuration and security

The server relies on a sandboxed environment to run code safely. It leverages WASI to provide a controlled system interface for executed programs, ensuring that code runs in isolation with a virtual file system and no network access unless explicitly enabled by your code.

Troubleshooting and tips

If the server fails to start, verify that Node.js and npm are available, and that the MCP client configuration correctly points to the server. Check that your environment allows executing child processes (required for npx) and that any required permissions for spawning processes are granted.

Examples

Example usage in an MCP client involves defining the mcpServers configuration as shown and then launching the Runno MCP Server to handle requests from your client.

Available tools

runCode

Executes code snippets using a configured runtime within the sandboxed environment.

WASI.start

Initializes and runs a WebAssembly WASI binary, setting up arguments, environment, and virtual filesystem access.

runFS

Runs code against a virtual filesystem, enabling filesystem interactions within the sandboxed runtime.