MCP-UI

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mcp_ui_server Overview ​

The mcp_ui_server gem provides server-side utilities in Ruby to help construct UIResource objects, which can then be sent to a client as part of an MCP response.

MCP Apps Compatibility

The create_ui_resource method creates UIResource objects that work with both MCP Apps hosts (via _meta.ui.resourceUri) and legacy MCP-UI hosts.

For the recommended MCP Apps pattern with TypeScript, see Getting Started.

Key Methods ​

  • McpUiServer.create_ui_resource(options): The primary method for creating UI snippets. It takes an options hash to define the URI, content (direct HTML or external URL), and encoding method.

Purpose ​

  • Ease of Use: Simplifies the creation of valid UIResource objects in Ruby.
  • Validation: Includes basic validation (e.g., URI prefixes matching content type).
  • Encoding: Handles Base64 encoding automatically.

Installation ​

Add this line to your application's Gemfile:

ruby
gem 'mcp_ui_server'

And then execute:

bash
$ bundle install

Or install it yourself as:

bash
$ gem install mcp_ui_server

See the Server SDK Usage & Examples page for practical examples.