[willtheperson]

If the connector is enabled by the prompt or via a UI interaction, it calls your MCP server. They have created some meta fields your tool can respond with, one of which is something about producing a widget along with a field for html.

In the current implementation, it makes an iframe (or webview on native) that loads a sandboxed environment which then gets another iframe with your html injected. Your html can include meta field whitelisted remote resources.