The Cockatrice Etiquette Primer - Cockatrice/Cockatrice GitHub Wiki

Before joining a game make sure that it's a recently created lobby and check if the game's description and format match your expectations. In the case that there are no empty lobbies available, don't hesitate to create your own!
When you join a game, say hi. Good-luck-have-funs are optional, but appreciated when returned. Small talk is often unwelcome. Just load your deck and ready up.
Once both players have readied up, roll a d20 ( default ctrl + i ). Whoever wins should say "ip", this is short for "I play" and indicates that you're taking the play. In the unlikely event that you win and take the draw, say so in full.
In EDH, get your commander from your sideboard by right-clicking the battlefield and selecting sideboard. Put them in the stack area.
Draw your initial hand ( default ctrl + m ). The player taking the play should either take their next mulligan or say "kp". Saying "kp" indicates you want to keep your hand. The player on the draw should then do the same. If you are on the draw, do not wait for your opponent to resolve all their mulligans; take turns doing mulligans so your opponent knows what's happening. If you're on the play, don't wait for your opponent to make a decision, as they're likely waiting on you. Once both players have said "kp" you can select cards and put them on the bottom of your library in a random order.
Play as if it's a physical table at your local game store. If a card asks you to name something, annotate the card. If you have to choose modes on a spell, say them in the chat. Use arrows to point at cards or people.
You can attach a card to your own or an opponent's cards in order to "exile under" something. Other cards that are removed from play but are likely to reenter later should be kept on the table but separate from the rest.
You can skip steps in the phase counter if nothing is happening in them, you can perform a default action associated with that step like drawing in the draw step by clicking that step twice or by using a keybind ( default shift + tab ).
Importantly, when you have a combat phase of more than one unblocked creature, use the combat phase marker. Indicate who is attacking, draw arrows from the creatures to the attacked player or planeswalker when needed, then click the Declare Blockers step. This is the equivalent of saying you're done with declaring attacks. The blocker should use arrows to block. If there are no blocks, they should just change their life total to indicate that they're taking the damage. If they start taking damage and you have a before-damage trick, you can play it anyway. They will adjust accordingly.
Use the Draw card action instead of dragging cards to you hard, only draws done using the Draw card action can be used with the Undo draw action if such an accident were to occur. In the unfortunate event that this is needed kindly ask your opponent if you should shuffle your deck to hide the known card again.
You can say "wait" or "think" at any time in chat to declare that you're holding priority whilst you consider a response. If your opponent has blue open, they may say "ok" after every spell - that's them passing priority. Some players might ask you "ok?" after each spell they cast - you can just say "ok" to allow the spell to resolve.
To end your turn, click the "end" phase marker. Do not pass turn! It is the job of the next player to use the Pass Turn button to begin their own turn ( default ctrl + enter, or shift + tab to untap automatically ). This is to allow your opponents to perform actions before your turn ends. So if it's the end of your opponent's turn, they'll be waiting for you to pass the turn to yourself.
Don't worry about having to undo something when your opponent responds a bit slower than you expected, this is normal just like when you play at your local game store.
You can customize keybinds and create new ones in the settings. You can also create keybinds to quickly send common chat messages there.
Don't forget to be nice to each other! In case of a dispute you can ask in the main chat if a judge or moderator can help you resolve it. You can use the block and buddy lists to maintain your level of comfort.

Taken from https://www.reddit.com/r/Cockatrice/comments/fohpnx/the_cockatrice_ettiquette_primer/ See notes, updates there - this might need changes. Good starting point. Put it here as reminder.

Also see https://www.reddit.com/r/Cockatrice/comments/8rke0a/etiquette_and_cockatrice_mechanics/