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.
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
UIResourceobjects 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'1
And then execute:
bash
$ bundle install1
Or install it yourself as:
bash
$ gem install mcp_ui_server1
See the Server SDK Usage & Examples page for practical examples.

