@startuml

!include skinparams.puml

actor "GUI program / Human user" as user

boundary "Engine CLI" as cli
control "Play a stone" as playStone
control "Think next move" as think
entity "Board state" as state

loop until desired board is set
    user -> cli : play stone
    cli -> playStone
    playStone -> state
    cli <- state
end

user -> cli : ask for move
cli -> think
think -> state
cli <- state : Show move

@enduml