Codemoder

An MCP proxy server that adds "code mode" capability to any MCP server. This lets AI models write JavaScript code that can call multiple tools in a single execution, instead of calling tools one at a time.

How it Works

┌─────────────────┐     ┌──────────────────┐     ┌────────────────────┐
│   MCP Client    │────▶│    codemoder     │────▶│ Downstream MCP     │
│   (Claude, etc) │     │                  │     │ Server             │
└─────────────────┘     └──────────────────┘     └────────────────────┘

The proxy:

1. Spawns and connects to a downstream MCP server
2. Intercepts list_tools and adds an execute_tools tool
3. Generates TypeScript interface definitions for all tools
4. When execute_tools is called, runs JavaScript code that can call tools
5. Proxies regular tool calls through to the downstream server

Usage

# Proxy any MCP server (simple form)
codemoder ./my-mcp-server

# With options, use -- to separate codemoder args from the command
codemoder --mode replace -- ./my-mcp-server

# Custom tool name
codemoder --tool-name "run_script" -- ./my-mcp-server

# Only include specific tools
codemoder --include-tools "move_items,get_footprints" -- ./my-mcp-server

Options

Option	Description	Default
--mode	add exposes both execute_tools and original tools; replace only exposes execute_tools	add
--tool-name	Name of the code execution tool	execute_tools
--include-tools	Comma-separated list of tools to include	all tools

Example

When connected through the proxy, the model can write:

// Get all items and sum their values
var items = tools.get_items({}).items;
var total = 0;
for (var i = 0; i < items.length; i++) {
  total += items[i].value;
}
({count: items.length, total: total})

Building

cargo build --release

The binary will be at target/release/codemoder.