Code Mode Bridge

An MCP (Model Context Protocol) multiplexer that connects to upstream MCP servers and exposes all their tools through a single sandbox_eval_js tool for unified orchestration and execution. Runs on Node.js and Deno. Bun is not officially supported — if you need to use Bun, ensure a container runtime (Docker or Podman) or Deno is available in your PATH so the bridge can delegate code execution to a supported executor.

Key Features

• Multi-server bridging: Connect to multiple upstream MCP servers simultaneously.

• Tool aggregation: Exposes all upstream functions through a single sandbox_eval_js tool.

• Dynamic discovery: Three built-in discovery tools let agents find and inspect available functions before writing code.

• Multi-executor sandbox: Secure execution via Deno, isolated-vm, Docker/Podman containers, or vm2.

• Automatic detection: Automatically selects the best available executor for your environment.

• Live reload: Watches mcp.json for changes and hot-reloads upstream connections without restarting.

• CLI management: Easy command-line interface for server configuration.

Quick Start

Installation & Run

# Run without installing
npx @ruifung/codemode-bridge

# Or install globally
npm install -g @ruifung/codemode-bridge
codemode-bridge run

Basic Usage

1. Add a server:

   codemode-bridge config add kubernetes --type stdio --command "npx" --args "-y,kubernetes-mcp-server@latest"

2. Start the bridge:

   codemode-bridge run

3. Use in your client: Point your MCP client (Claude Desktop, VS Code, etc.) to npx @ruifung/codemode-bridge.

Discovery Tools

The bridge exposes three tools for discovering what's available before writing sandbox_eval_js code:

Use these before calling sandbox_eval_js to find the correct function name and parameter types.

Using the sandbox_eval_js Tool

The sandbox_eval_js tool executes JavaScript in a sandboxed environment with access to all upstream functions via the codemode object. You can write either a function body or a complete async arrow function:

// Function body (auto-wrapped):
const result = await codemode.server_name__function_name({ param: "value" });
return result;

// Or as a complete async arrow function:
async () => {
  const result = await codemode.server_name__function_name({ param: "value" });
  return result;
}

Documentation Index

• Architecture: How the bridge works, project structure, and logical flow.

• Executors: Detailed comparison of sandbox backends (Deno, isolated-vm, Containers).

• CLI & Configuration: Full command reference and configuration format.

• HTTP Serve Mode: Multi-client HTTP transport, session isolation, and security.

• Integration Guide: Setup instructions for Claude Desktop, VS Code, and more.

• Development: Build and test instructions for contributors.

• Sandbox Hardening: Security details for the execution environments.