Submit page has a link to idnits at author-tools that always produces an error.

[rjsparks]

Following the current link on https://datatracker.ietf.org/submit/ to

https://author-tools.ietf.org/api/idnits

always results in

{"error":"URL is missing"}

A different user experience is needed. Perhaps pointing to the main author-tools page and add prose to the datatracker page saying to use the Validate functionality there.
Or build a URL at author-tools that allows a friendlier guided experience into validating a document.