WRIT Prerequisite Guard

If you sell in a sequence — the machine before the pods, the starter kit before the refills, a certification before the pro line — buyers must earn access, but Shopify can't gate on what a company has actually bought. Prerequisite Guard closes that gap. Set a rule (a gated product, the prerequisite it requires, how many units) and a server-side checkout function blocks the gated item for any B2B company that hasn't purchased the prerequisite yet. It counts every order per company, so the gate opens automatically the moment they qualify. Retail and non-gated products always check out.