The six default-blocked patterns
Per Shopify's Editing-robots-txt help page, the default-blocked patterns are: /admin (the merchant admin), /cart (the cart page), /checkout (the checkout flow), /collections/*+* (filtered collection URLs that produce duplicate content), /search (internal search results pages), and /policies/ (auto-generated policy pages). The verbatim rendered /robots.txt on a default Shopify store shows these as Disallow rules under the User-agent: * block.
/admin, /cart, /checkout — the security blocks
The first three blocks are security and UX protections. /admin is the Shopify merchant admin; no public crawler should ever index it. /cart is the customer's shopping cart, which is empty for any crawler and uniquely stateful for any logged-in customer — neither is content worth indexing. /checkout is the payment flow, and indexing it would be a security and UX disaster (Google deep-linking customers into a half-rendered checkout). Each block exists because there is no version of the page that would be valuable in search.
/collections/*+* — the filter duplicate block
The /collections/*+* pattern is a robots.txt wildcard matching any collection URL with a + character in the path. The + is how Shopify's native multi-facet filter system serializes selections — /collections/dresses/red+xl, /collections/shoes/leather+size-9. The wildcard catches all such combinations. The block exists to suppress combinatorial duplicate-content explosion: a 10-facet collection generates thousands of URL combinations, most with overlapping content and no search demand. Google's faceted navigation guidance treats this as a primary cause of wasted crawl budget on ecommerce sites.
/search and /policies/ — the thin-content blocks
The /search block prevents indexing of internal search result pages — infinite combinations, all thin. The /policies/ block prevents indexing of the auto-generated policy pages (refund policy, shipping policy, terms of service, privacy policy) that Shopify generates at /policies/refund-policy, /policies/shipping-policy, etc. The policy block is a platform-aesthetic choice: Shopify wants the canonical policy URLs to be the merchant's custom pages (typically at /pages/refund-policy), not the auto-generated versions.
Why you should never unblock any of these
The six default blocks were chosen by Shopify's SEO team after analysing patterns across millions of stores. They reflect best practice for the ecommerce category. Unblocking any of them introduces a known problem with no upside: /admin would surface merchant URLs in search; /cart and /checkout would create privacy and UX problems; /collections/*+* would dilute crawl budget across thousands of thin URLs; /search would expose infinite combinatorial search result pages; /policies/ would create canonical conflicts with the merchant's customised /pages/ versions. Shopify's verbatim warning applies: 'Incorrect use of the feature can result in loss of all traffic.'