Automatically Add And Remove Tags From A Product in Shopify by Using
Arigato Automation

This automation will add or remove tags from products based on the variant's inventory levels. 

This automation removes specific size based tags from products once their inventory level reaches 0

This workflow fires when product inventory goes to zero. Rather than remove the product from the store entirely, when inventory goes to zero, a recently sold tag is added to the product. If the product comes back in stock, the tag will be added again.