Happy slice of mcp pizzaMCP.pizza

tidewave_rails

MCP.Pizza Chef: tidewave-ai

Most coding assistants only ever see your source files. This gives one a line into the app while it is actually running in development, so it can check rather than guess. It can evaluate code with your real loaded data, run SQL against the development database, read the server log after a request, find where a class or method is genuinely defined even when it was generated at runtime, and read documentation pinned to the exact gem versions in your lockfile.

Coding

Use This MCP server To

Ask the agent to run code against my live app Have it read the server log after a failed request Query the development database without leaving chat Find where a method is really defined Get docs for the exact gem version I am on Insert test records to see how a page looks

README

Tidewave Rails

Tidewave Rails is an MCP server that provides runtime-level tools for developing Ruby on Rails apps using coding agents.

Your agent will be able to use this MCP server to talk to your running Rails app in development to:

  • execute code in the context of the running app (like a Rails console for agents)
  • read the app's live logs
  • query your development database
  • get source locations of classes and methods
  • read documentation pinned to the exact gem versions your app depends on

This MCP server is an open-source component of Tidewave, the agentic development environment for Rails and Phoenix.

You can use this project as a standalone MCP server or integrated with the Tidewave product by following the instructions below.

Installation

1. Add the Tidewave gem to your app

You can add Tidewave Rails to your app by running:

bundle add tidewave --group development

or by manually adding the tidewave gem to the development group in your Gemfile:

gem "tidewave", group: :development

2. Add the Tidewave MCP to your agent/editor

Add the Tidewave MCP server to your editor or MCP client configuration as the type "http" (streamable), pointing to the /tidewave/mcp path and port your web application is running at. For example, http://localhost:3000/tidewave/mcp.

We also have specific instructions for:

Usage

As with any other MCP server, your agent will call the tools exposed by the Tidewave MCP whenever it sees fit. But you can also prompt it to call them explicitly.

tidewave_rails FAQ

Can I use this to let an agent query my development database?
Yes — it runs SQL against it and hands the rows straight back.
Which apps does it work in?
Claude Code, Codex, Cursor, Neovim, OpenCode and VS Code all have their own setup pages.
Do I need an API key?
No. It points at your own app running on localhost.
How hard is setup?
Add one gem to the development group, then point your editor at the app's /tidewave/mcp address.
Is this safe to run in production?
It is meant for development only, which is why it installs into the development group of your Gemfile.
Why is there no tool for listing routes?
Deliberate. The authors found agents do better reading the route file directly, so the tools fill gaps that reading cannot.