Corex MCP

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Corex ships a self-hosted Model Context Protocol (MCP) server. Your running Phoenix app exposes the component registry and docs to tools such as Cursor, Claude Desktop, or VS Code, without an external SaaS.

The server builds on Tidewave Phoenix (Apache License 2.0).

1. Install Corex

def deps do
  [
    {:corex, "~> 0.1.0-beta.5"}
  ]
end
mix deps.get

2. Mount the MCP plug

In lib/my_app_web/endpoint.ex, add plug Corex.MCP after Plug.Static and before the if code_reloading? do block.

if Mix.env() == :dev do
  plug Corex.MCP
end

3. Run the app

MCP listens on the same host and port as Phoenix (for example http://localhost:4000). Start the server before connecting a client.

4. Configure your MCP client

Use http://localhost:4000/corex/mcp (adjust host and port to match your app).

Cursor

Project file .cursor/mcp.json:

{
  "servers": {
    "corex": {
      "url": "http://localhost:4000/corex/mcp"
    }
  }
}

Claude Desktop

In ~/Library/Application Support/Claude/claude_desktop_config.json, under mcpServers:

{
  "mcpServers": {
    "corex": {
      "transport": {
        "type": "http",
        "url": "http://localhost:4000/corex/mcp"
      }
    }
  }
}

VS Code

In settings.json:

{
  "mcp.servers": {
    "corex": {
      "url": "http://localhost:4000/corex/mcp"
    }
  }
}

Generic MCP client

{
  "name": "corex",
  "url": "http://localhost:4000/corex/mcp"
}

5. Available tools

All tools are read-only and safe to call repeatedly.

list_components

Returns every Corex component id from the package registry (strings such as accordion or date_picker). Use this before get_component when you need a valid id.

Arguments: none (empty object).

Result: JSON with a components array of id strings.

get_component

Returns metadata for one component: Elixir module, function component names and arity, Markdown module documentation when available, source_path when known, and docs_note when docs are missing or not Markdown.

Pass id exactly as returned by list_components.

Arguments:

  • id (string, required) - e.g. accordion, data_table

Result: JSON object with the registry payload plus docs, docs_note, source_path, and related fields.

installation_guide

Returns copy-paste steps for installing Corex on a new project (mix corex.new), an existing Phoenix app, or both. It does not run shell commands.

Arguments:

  • scenario (string, optional) - one of new_project, existing_project, or all (default all).

Result: JSON with structured steps, commands, and reference URLs (hexdocs_corex, manual_installation, repository).