There is no Slug field, and { slug: true } doesn’t work either. Suggestions about addons don’t work and ChatGPT has no clue.
The idea of having an input type which processes or masks what a user is typing is something that Cockpit does not yet possess.
In the case of a “slug”, it could be a read-only field that reads and processes an entry from another field. This could be done with either Javascript or PHP. Alternatively, one could create a slug from the entered content one the user has finished typing. This can also be done with Javascript or with PHP (via AJAX).
Personally, I would like to see read-only fields whose content is a unique reference, that has tested itself against the existing Database and has proved itself to be unique.
I have created both in the past for a particular site but have not done it as an installable plugin. I have not had the need. If there was a need in the Community for this type of plugin which could do these sort of things and be extended by the Developer, to do even more, I would be willing to write it. However Artur and his Team have not published a Marketplace solution which would allow Developers such as ourselves at Webcliq, to earn a small amount for each plugin sold / provided.