Install DutyLookout
DutyLookout installs from the Shopify App Store, so the permission prompt and billing stay inside your Shopify admin where you can audit them. It reads your products and writes back an HS code you approve; it never touches customer data. No subscription — your first 25 classifications each month are free.
Installing takes one click from inside your Shopify admin — you will not be asked to type your store address anywhere.