How to solve the error " Could not determine command name from tag @command" with Drush?
The comment on the traderbot method is incorrect:

   * @command 
   * @aliases tb,traderbot


There is no value after @command. I believe you want:

   * @command traderbot
   * @aliases tb


See: Porting Commands to Drush 9

Clear the cache after the change and try again.