Colour, size and price filters quickly create many combinations. Not every combination deserves an independent search page. Before editing Shopify rules, decide which selections provide distinct content and which merely change how the same collection is displayed.
Shopify delivers a default robots.txt. Customising robots.txt.liquid requires deliberate technical review. Opening crawling broadly in response to one Search Console message can expose many additional parameter addresses.
Compare three actual addresses
Record the unfiltered collection, one selected filter and a combined selection. Describe what products and explanatory content really change, then inspect the status, canonical and matching robots rule.
A fictional record can deliberately preserve the unresolved decision:
Collection: Wall lamps
Filter: colour=black
Distinct buying guidance or just a smaller selection?
Intended search entry point: undecided
A robots block prevents fetching but does not reliably remove a known URL from the index.
Assess changes in a theme copy and preserve the current template. Compare the delivered robots.txt before and after the change so that unrelated default rules remain intact. Later, monitor whether unnecessary combinations appear. A public page targeting a distinct search task needs useful content and meaningful internal links; allowing a parameter does not create that value.