Does X tell you if you are shadowbanned?

Suspensions and locks are different: those come with an explicit notice. For visibility limits, the only workable approach is comparison — what a logged-out observer sees versus what you see logged in — and repeating it over time.

That asymmetry is exactly why third-party checkers exist, and also why none of them can be authoritative. Treat any tool that claims to read an official shadowban flag with suspicion.