Mission Briefing

• WOTC Official Reminder Textofficial rules
  Surveil — Look at the top N cards of your library. Put any number of them into your graveyard and the rest on top of your library in any order.

• WWizards of the Coast2018-10-05
  Official Ruling
  The instant or sorcery card you choose may be one that you just surveilled into your graveyard.
• WWizards of the Coast2018-10-05
  Official Ruling
  If you cast a spell this way and that card is exiled, it's considered a new object in the zone it's put into. It won't be exiled if it's put into your graveyard later in the turn.
• WWizards of the Coast2018-10-05
  Official Ruling
  Mission Briefing is still on the stack while you choose an instant or sorcery card in your graveyard. Your Mission Briefing can't be to give yourself that same Mission Briefing.
• WWizards of the Coast2018-10-05
  Official Ruling
  Mission Briefing doesn't change when you can cast the chosen card. For example, if you choose a sorcery card, you can cast it only during your main phase when the stack is empty.
• WWizards of the Coast2024-01-12
  Official Ruling
  You perform the actions stated on a card in sequence. For some spells and abilities, you'll surveil last. For others, you'll surveil and then perform other actions.
• WWizards of the Coast2024-01-12
  Official Ruling
  When you surveil, you may put all the cards you look at back on top of your library, you may put all of those cards into your graveyard, or you may put some of those cards on top and the rest of them into your graveyard.

Rulings via Scryfall