SpaceX currently plans to catch both Booster and Starship with the 'chopstick' arms on the side of the launch tower. This is a highly complex procedure that has not been tested before, and initial attempts could be physically and finacially destructive.

This market will resolve after the completion of the next OFT.

If it resolves YES, this takes into account the possibilities of inflight failures. 

If it resolves NO, this removes the possibility of SpaceX announcing 'no attempt', then changing their plan.

The catch attempt can be made either for the Booster or Starship itself (or both).

'Attempt' will be defined as either vehicle making a clear approach run on the launch site. If the approach is aborted before the chopsticks have moved, the attempt will still be considered valid.

It seems to me that in practice, these approach runs can be considered to have started after Booster's boostback burn, and after Starship survives atmospheric reetry and places itself on the correct trajectory. I am open to discussion on this point, but I think other criteria would be more subjective. 