// builtin tools · 06
Terminal and harness control tools
Terminal tools close a turn explicitly. They are the concrete shape of Action-or-Terminate: each turn must act or finish with a structured signal.
params respond terminal Talks to the user and ends a conversational turn. task_complete terminal Requests completion; accepted only after exit criteria pass. task_blocked terminal Declares a structured blockage reason. need_input terminal Asks the user for information required to continue.
If a model says it will act but emits no tool, the harness rejects the turn and asks for a real action or terminal signal.