Operational will mean that a launch has happened from the tower (full stack or just booster or ship by itself), or a catch (of either booster or ship) has been attempted. "Attempted" will mean that it was announced as the plan for the flight and the flight launched, even if the flight was not successful or the catch was aborted.

All dates are "on or before".

Current plans are that this launch tower will also be at Starbase, however that is not required. An operational tower at Cape Canaveral or elsewhere would also count.

Related question with different criteria:
/Blomfilter/will-starbase-mount-a-starship-on-a