mendix-marketplace-mcp-proxy

MCP-to-MCP proxy for the Mendix Marketplace MCP endpoint.

Connects to the official Mendix Marketplace MCP server via Streamable HTTP, discovers its tools and prompts dynamically, and re-exposes them over stdio — making them accessible to Claude Code and other MCP clients that only support stdio transport.

Why a proxy?

Claude Code's MCP transports don't directly support Mendix's Streamable HTTP endpoint:

• HTTP transport requires OAuth discovery, which Mendix doesn't implement

• SSE transport uses GET, but the endpoint only accepts POST

This proxy bridges the gap: Claude Code ←stdio→ proxy ←StreamableHTTP→ Mendix.

Related MCP server: slack-mcp-claude-auth

Setup

npm install

Authentication

Get a Personal Access Token (PAT) from Mendix Developer Settings.

Set it as an environment variable:

export MENDIX_PAT=your-token-here

Usage

With Claude Code

claude mcp add mendix-marketplace-mcp-proxy -e MENDIX_PAT=your-token -- npx tsx /path/to/mendix-marketplace-mcp-proxy/src/index.ts

Standalone

npm run dev    # Development (tsx)
npm run build  # Compile TypeScript
npm start      # Production (node)

How it works

1. Connects to the Mendix MCP endpoint as a client using StreamableHTTPClientTransport

2. Discovers all available tools and prompts via tools/list and prompts/list

3. Registers them on a local MCP server with identical schemas

4. Forwards tool calls and prompt requests to the upstream, returns results

5. Serves everything over stdio

No hardcoded tool definitions — if Mendix adds new tools or prompts, they appear automatically.

Environment variables