Isolator MCP Server

What is Isolator MCP Server?

Isolator MCP Server is a Model Context Protocol (MCP) server written in TypeScript that wraps an embedded Go CLI tool to provide a secure code execution sandbox. It allows LLM applications (MCP hosts) to safely run Python, Go, or JavaScript code snippets in isolated Docker containers.

How to use Isolator MCP Server?

1. Build the embedded Go CLI (isolator-cli/isolator) using go build. 2. Configure isolator_config.json with the absolute path to the built binary, language images, and optional prompts directory. 3. Install server dependencies with npm install and compile with npm run build. 4. Add the server to your MCP host settings file (e.g., cline_mcp_settings.json) with command: "node" and the path to build/index.js. The server connects via stdio. Ensure required Docker images are pulled beforehand.

Key features of Isolator MCP Server

• Provides the execute_code MCP tool for running code.
• Supports direct code or pre-defined snippet files.
• Multi-language support: Python, Go, JavaScript.
• Uses Docker containers for secure, isolated execution.
• Configurable security defaults (timeout, resource limits, network).
• Returns structured results (stdout, stderr, status) via MCP.

Use cases of Isolator MCP Server

• Safely executing user‑provided code snippets without host risk.
• Running pre‑defined code examples from a snippet library.
• Testing and verifying code logic within an LLM-driven workflow.
• Automating code execution tasks in development or CI contexts.

FAQ from Isolator MCP Server

What are the prerequisites for running Isolator MCP Server?

Docker (daemon running), Go to build the CLI, and Node.js with npm for the TypeScript server.

Does Isolator MCP Server automatically download Docker images?

No. The Docker images specified in isolator_config.json (e.g., python:3.11-alpine) must be pulled manually using docker pull before use.

How do I configure the server’s security settings?

Edit isolator_config.json to adjust timeout, resource limits, network access, language images, and the path to the isolator Go binary.

What transport does Isolator MCP Server use?

The server communicates over stdio (standard input/output) with the MCP host.

How does code execution work end-to-end?

The MCP host calls the execute_code tool; the server writes code to a temp directory, spawns the Go CLI which creates a Docker container, copies files, runs the code, captures output, and returns the result to the host.