Currently we treat all toolinfo descriptions as plain text, but we could support CommonMark if we wanted rich text support.
https://commonmark.org/ is a variant of Markdown that has implementations in many programming languages. It is used in standards like OpenAPI to provide a reasonably safe way to add rich text without the risks of full HTML support. It is also well documented for end users.
+1. This would be really useful, especially for inline links and simple text formatting.
I think this would be mostly a matter of UI support for editing and rendering and maybe a small amount of documentation. We should be able to find a 3rd party Vue component or other library for both the rendering and rich editing of commonmark.
Having a full-fledged WYSIWYG editor would definitely be nice, but for now i would start simple and just support it when rendering the description. Maybe a second step could be to have a preview option next to the edit box. There are definitely many Vue components that are able to do something like this.