Module: ActionMCP::Apps

Defined in:
lib/action_mcp/apps.rb

Overview

Constants and helpers for the MCP Apps extension (ext-apps, SEP-1865, stable 2026-01-26). See: github.com/modelcontextprotocol/ext-apps/blob/main/specification/2026-01-26/apps.mdx

Constant Summary collapse

EXTENSION_KEY = 
"io.modelcontextprotocol/ui"
VISIBILITY_VALUES = 
%w[model app].freeze
URI_SCHEME = 
%r{\Aui://\S+\z}
MIME_TYPE = 
MimeTypes::APP_HTML
EXTENSION_SETTINGS = 
{ mimeTypes: [ MIME_TYPE ] }.freeze
CSP_KEYS =

‘_meta.ui.csp` directive keys per ext-apps spec.

%i[connectDomains resourceDomains frameDomains baseUriDomains].freeze
PERMISSION_KEYS = 
%i[camera microphone geolocation clipboardWrite].freeze
CONNECT_ORIGIN_PATTERN =

The stable MCP Apps spec allows WebSocket endpoints for connect-src only.

%r{\A(?:https?|wss?)://[^\s"'<>]+\z}
RESOURCE_ORIGIN_PATTERN = 
%r{\Ahttps?://[^\s"'<>]+\z}

Class Method Summary collapse

Class Method Details

.client_supports?(client_capabilities) ⇒ Boolean

Returns:

  • (Boolean) 


28
29
30
31
32
33
34
35
 
# File 'lib/action_mcp/apps.rb', line 28

def client_supports?(client_capabilities)
  settings = client_capabilities&.dig("extensions", EXTENSION_KEY) ||
             client_capabilities&.dig(:extensions, EXTENSION_KEY)
  return false unless settings.is_a?(Hash)

  mime_types = settings["mimeTypes"] || settings[:mimeTypes]
  Array(mime_types).include?(MIME_TYPE)
end

.extension_settings ⇒ Object 



24
25
26
 
# File 'lib/action_mcp/apps.rb', line 24

def extension_settings
  EXTENSION_SETTINGS.deep_dup
end