Covetous Dragon

• WWizards of the Coast2004-10-04
  Official Ruling
  The ability will trigger if you don’t control an artifact, even for a brief moment during the resolution of another spell or ability.
• WWizards of the Coast2004-10-04
  Official Ruling
  The ability only checks if you control no artifacts at the time it triggers. It does not check again on resolution. So gaining control of an artifact before then will not save the Dragon.

Rulings via Scryfall