Tidewave Rails — Claude Code MCP server: what it does, how to install
Connects coding agents to a live Ruby on Rails application over HTTP. Lets models evaluate code in runtime, query databases, and resolve method locations.
Open on GitHubWhat Tidewave Rails does
This server connects coding agents to your running Rails development process via HTTP. Through the project_eval tool, the agent runs Ruby snippets inside the application context, inspecting memory state and standard output. The execute_sql_query tool lets the model inspect database records directly by running SQL against the development database.
For code navigation, get_source_location returns the file and line number for classes and methods. It inspects running Ruby objects, so it resolves metaprogrammed methods and gem code without grepping. The get_docs tool fetches reference manuals locked to the exact gem versions defined in Gemfile.lock.
Tidewave Rails enforces development-only usage: it raises an error whenever code reloading is disabled. By default, incoming connections are accepted strictly from localhost.
What it helps with
- evaluate Ruby expressions inside the live application context
- query the development database using direct SQL statements
- locate definitions for metaprogrammed methods across gems and project files
- fetch documentation locked to specific versions in Gemfile.lock
Example prompts for the agent
- Run User.count in the running application and show the return value
- Execute a SQL query to check recent entries in orders
- Find the exact file and line where authenticate_by is defined
How to install Tidewave Rails
Install
The MCP registry has no launch command for it: see the repository README
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about Tidewave Rails
How to install Tidewave Rails in Claude Code?
Add the gem to development dependencies with bundle add tidewave --group development. Next, register an HTTP MCP server pointing to http://localhost:3000/tidewave/mcp.
What does Tidewave Rails do?
It connects AI coding agents to a running Rails application. The model can evaluate Ruby code, inspect the database, and look up methods directly in runtime.
Can Tidewave Rails run in production?
No, the server is built strictly for development environments. It will raise an error if started in an environment where code reloading is turned off.
