How to restrict the number of selected items to perform a bulk action

Question

I'm working on data-heavy B2B platform. We have a list with bulk actions - you need to select some list items and then click bulk action you want to perform. What we try to do is to restrict the number of selected items needed to perform a bulk actions (some of them are heavy).

The hard part of this problem is that each action can have its own limit, eg.
Actions 1, 3, 5 - max. 20 items selected
Actions 2, 4 - max. 50 items selected

For bulk actions we have multi-level menu, something like Group 1: Action 1, Action 2, Action 3, Action 4, Action 5, Action 6; Group 2: Action 1, Action 2, Action 3, Action 4 ecc.

Do you have any idea on how to inform users that there is any limit? Should I add text clues to each button, like Action 1- select max. 20 items, Action 2 - select max 50 items?

What should happen after selecting too many items?

The ideal situation, when all bulk actions have the same limits, is not possible at this time.

Answer 1

A. Action - Selection - Start

Suppose user first selects action. Is so, you can display action limit and number of selected items like: Selected 20 from 20 or Left 0 from 20. You just decrement/increment indicator while user selects/deselects item.

B. Selection - Action start

Suppose user first selects items. If so, he can select as many items as he want. After starting action you can warn him that selection exceeds limit and ask to proceed or cancel or just do action on maximum number of items. In this case limit might be added to action name if this is critical to system - Action 1 [20]. Otherwise, you may have separate reference screen with the table action limits to minimize visual noise on button labels.