r33drichards/mcp-js

mcp-v8: V8 JavaScript MCP Server

A Rust-based Model Context Protocol (MCP) server that exposes a V8 JavaScript runtime as a tool for AI agents like Claude and Cursor. Supports persistent heap snapshots via S3 or local filesystem, and is ready for integration with modern AI development environments.

• Async Execution Model: run_js returns immediately with an execution ID. Poll status with get_execution, read console output with get_execution_output, and cancel running executions with cancel_execution.
• Console Output: Full support for console.log, console.info, console.warn, and console.error. Output is streamed to persistent storage during execution and can be read in real-time with paginated access (line-based or byte-based).
• Async/Await Support: Full support for async/await and Promises via the deno_core event loop.
• V8 JavaScript Execution: Run arbitrary JavaScript code in a secure, isolated V8 engine.
• TypeScript Support: Run TypeScript code directly — types are stripped before execution using SWC. This is type removal only, not type checking.
• WebAssembly Support: Compile and run WASM modules using the standard WebAssembly JavaScript API (WebAssembly.Module, WebAssembly.Instance, WebAssembly.validate).
• ES Module Imports: Import npm packages, JSR packages, and URL modules using Deno-style import syntax. Packages are fetched from esm.sh at runtime — no npm install needed. (e.g., `import { camelCase } fro

Works with Claude (desktop and mobile), Cursor, Windsurf, VS Code, and any MCP-compatible AI app.

Category: Developer Tools