One of my players is using a homebrew Witch class created by the podcast Worlds Beyond Number with my blessing. Essentially it's a Wisdom-based wizard who can heal and whose powers revolve around curses and imbuing items with their spells. They can create Talismans (indefinitely 'losing' a spell slot to create a magic item that allows anyone to cast one of their spells 1/day) and Tokens (items that allow anyone to cast one of their spells exactly once).
The wording of their 'Tokens' feature leaves it unclear whether a spell slot is expended if the artisan's tools check doesn't fail by 5 or more:
Any 1st-level witch spell that targets one or more creatures can be crafted into a token with 1 hour of labor. To craft it, you must have an unexpended spell slot of a high enough level to cast the spell (you need not have the spell prepared) and you must succeed on a Wisdom check using artisan's tools with a DC of 10 + the spell's level. On a failure, the item isn't created; if the check fails by 5 or more, you also expend a spell slot of the spell's level.
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You can attempt to make a single token during a short or long rest.
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You can maintain a number of active tokens equal to your proficiency bonus.
Does the text imply that a spell slot is expended upon successfully creating a token? That would make narrative sense but RAW, it sounds like it isn't.
This feature already allows Witches at any level to come into each day with 2-6 extra spell slots (the level of spell increasing at higher levels) compared to every other full-caster, but if a spell slot is not expended upon successfully creating a token and a token can be made each short rest, then doesn't that mean that Witch's spell slots are only limited by the number of short rests they can take? My player's +6 bonus in Wisdom (artisan's tools) makes it impossible for her to fail this check by 5 or more. As long as a Witch has at least one unexpended 1st-level spell slot, they could take 5 hours of short-resting to generate five extra spell slots with no drawbacks or risks. A 1st-level Witch could use this method to have 9+ spell slots per day.
Is my interpretation wrong? And if not, is this wildly unbalanced like the dreaded coffeelock?
For context, my player is very cooperative and would accept it if I nerfed her character - I just don't want to unnecessarily stomp on anyone's fun.