Garc33 Js Sandbox MCP Server

The js‑sandbox MCP Server is a lightweight, Model Context Protocol endpoint that gives AI assistants like Claude the ability to execute arbitrary JavaScript code safely. By exposing a single tool, it removes the need for developers to build and maintain their own sandboxed runtimes whenever they want an AI agent to run scripts, manipulate data structures, or test algorithms on the fly. This solves a common pain point: how to let an AI safely run code without risking system compromise or leaking sensitive data.

When a client invokes , the server spawns an isolated JavaScript environment, runs the supplied code under user‑defined constraints, and returns the result. Developers can control timeout (between 100 ms and 30 s) and memory usage (from 1 MB to 100 MB), ensuring that runaway scripts or memory‑hungry operations cannot affect the host machine. The sandbox is hardened against malicious payloads, providing a trusted execution layer that respects the boundaries set by the AI workflow.

Key capabilities include:

• Secure isolation: Each execution occurs in a fresh, sandboxed context that cannot access the host file system or network.
• Resource limits: Fine‑grained control over CPU time and memory protects the host from denial‑of‑service attacks.
• Simple API: A single tool with clear parameters (, , ) makes integration straightforward for MCP clients.
• Extensibility: The server can be extended to expose additional tools (e.g., file I/O, HTTP requests) while preserving the same security model.

Typical use cases are plentiful: a Claude agent could analyze user‑provided data, generate dynamic visualizations, or prototype algorithms before committing them to production. In educational settings, students can experiment with JavaScript code through an AI tutor without installing a local runtime. Enterprises can allow internal bots to run scripts on proprietary data while keeping the execution sandboxed from external threats.

Integration into existing AI workflows is seamless. Developers add a single entry to the file, pointing to the compiled JavaScript server. Once registered, any Claude workflow can call as part of its toolset, receiving immediate feedback from the sandbox. Debugging is facilitated by the MCP Inspector, which exposes a browser‑based UI for inspecting tool calls and server logs. Overall, the js‑sandbox MCP Server delivers a secure, configurable, and developer‑friendly bridge between AI assistants and JavaScript execution, enabling richer, safer interactions without the overhead of managing isolated runtimes manually.