@rqlang/mcp

An MCP server that teaches AI assistants to write rqlang .rq files correctly. It works with any MCP client that can launch a local server: Claude Code, Claude Desktop, Cursor, Windsurf, VS Code, Codex, Gemini CLI, Zed and others.

It authors and checks .rq files; it never sends a request. Everything runs locally on Node.js 18 or newer, with the rqlang parser compiled to WebAssembly, so there is no native binary to install.

Setup

The server speaks MCP over stdio. Every client launches it with the same command:

npx -y @rqlang/mcp

Start the client from your project folder: tools that take no path use the folder the server runs in.

Claude Code

claude mcp add rq -- npx -y @rqlang/mcp

Codex CLI

codex mcp add rq -- npx -y @rqlang/mcp

Claude Desktop, Cursor, Windsurf, Gemini CLI and other clients configured through a JSON file (claude_desktop_config.json, .cursor/mcp.json, ~/.codeium/windsurf/mcp_config.json, ~/.gemini/settings.json, …):

{
  "mcpServers": {
    "rq": {
      "command": "npx",
      "args": ["-y", "@rqlang/mcp"]
    }
  }
}

VS Code: install the rq extension, which registers this same server for Copilot with nothing to configure.

What it provides

Kind	Name	Purpose
Tool	validate_rq	Parses and analyzes a snippet against the files around it; returns syntax and semantic diagnostics with line and column
Tool	lint_rq	Checks a snippet against the rqlang idioms; returns rule-tagged diagnostics with a suggested fix
Tool	list_requests	Lists the requests already defined under a path, so new ones do not collide
Tool	get_rq_reference	Returns the rqlang grammar reference or the idioms guide
Resource	rqlang://docs/language-definition	The rqlang grammar reference
Resource	rqlang://docs/idioms	The rqlang idioms guide
Prompt	generate_rq	Drives the generate → validate → lint → iterate loop for a natural-language intent

Drafts passed to validate_rq and lint_rq are checked in memory and never written to disk. Imports resolve against workspace_path, or against the folder the server runs in when it is omitted.

License

MIT