Currently, listings in Catalog have a field for "Cap" - which is intended to limit the number of registrants in a section.
However, this "Cap" in Catalog is independent of Canvas & does not account for Canvas registrants.
For example, consider a Catalog listing with a cap of 30. If an administrator enrolls a student to this class directly from Canvas (instead of Catalog), that student is not considered & the number of available seats remains the same - potentially allowing for 31 total students.
Canvas sections could have a separate & optional field for a "Cap", which would automatically populate when creating the corresponding Catalog listing.