I keep encountering this issue on AO3 where while looking for fics since I tend to search for fics by pairing.

As a generic example to explain what I mean I’ll use Stiles/Lydia Martin from Teen Wolf.

If you just search Teen Wolf fics by Stiles/Lydia pairing you are almost instantly going to find hundreds of Sterek fics that feature Stydia as a past relationship, or as friends despite being tagged as the pairing.

Alternatively; fics that might just in passing reference a ship as supporting characters will still wind up tagging that pairing too leading to the Stydia search resulting in mostly Sterek and Scott/Allison fics that make general references to Stydia.

I think AO3 would be well served by adding the ability to specify if you are looking for a fic where the specific ship is the main pair or a fic where the ship are supporting characters. It would certainly save me hours of page flipping trying to find stories that actually meet what I’m looking for.

And before anyone suggests excluding certain pairings from the search; in many fandoms the best fics I’ve ever read would be ones I’d never have seen if I excluded certain ships.