Building a Remote MCP Server in Ruby on Rails, A Production Guide

Most MCP tutorials are Python or Node.js.

This is the Rails version, built in production, serving real users, powering an AI agent inside a SaaS product.

Here's the architecture, the key decisions, and the gotchas that cost us time.

What MCP Actually Is

Model Context Protocol is a standard for connecting AI models to external tools and data sources.

Before MCP, you'd give Claude a document and ask it questions. After MCP, Claude can call your API, read your database, take actions in your product, all from a conversation.

The protocol is simple: JSON-RPC 2.0. Claude sends requests, your server responds.…