The protocol for GDL-II players differs slightly from the one for "regular" GDL. There are still START, PLAY and STOP messages, but the PLAY and STOP were extended by two new fields, <TURN> and <LASTMOVE>. The START message was not changed.
The new message formats are:
- (PLAY <MATCHID> <TURN> <LASTMOVE> <PERCEPTS>)
- (STOP <MATCHID> <TURN> <LASTMOVE> <PERCEPTS>)
- .. the match ID of the match the message belongs to
- .. an integer counting the number of turns. Turn is 0 for the first play message and increased by 1 on every subsequent play or stop message.
- .. the move that was executed by the player on the last turn (=NIL for the first play message). This tells the player which move was selected for it by the game master in case no move was submitted or the submitted move was illegal.
- .. the percepts seen by the player according to the sees rules (=NIL for the first play message).