Struct GoalGate 

pub struct GoalGate { /* private fields */ }

The core hook for the --goal goal-driven loop, subscribing to two events (dispatched via the hook_event envelope):

• after_session_enter: Injects the goal description + goal_done usage contract as additional_context into the system prompt suffix — effective from turn 1. This lets the model know the goal and that it must actively call goal_done upon completion from the start, avoiding an extra wasted turn waiting for the first voluntary stop.
• before_turn_end: On voluntary turn stop, reads GoalState::is_reached: if reached (model called goal_done) → proceed to end; otherwise → continue to extend the turn + inject an English prompt reminder.

The hard cap on extensions is enforced by the turn loop’s crate::session::TurnConfig::max_hook_continues (mapped from --max-turns) — this hook only checks “is it done?”, it does not count extensions itself.

Like SkillManifestHook, this is a stateful builtin (holds Arc<GoalState>) and cannot be constructed via BuiltinRegistry::defaults’s parameterless factory — during CLI assembly, a closure capturing the state is registered for both events under --goal (see defect_cli::hooks).

Implementations

impl GoalGate

pub fn new(goal: Arc<GoalState>) -> Self

Trait Implementations

impl StepHandler for GoalGate

fn handle_step<'a>( &'a self, envelope: &'a Value, _ctx: HookCtx<'a>, ) -> BoxFuture<'a, Result<Option<Value>, HookError>>

Dispatches on the envelope’s hook_event:

• after_session_enter → injects goal description and contract (additional_context)
• before_turn_end → if reached, proceed; otherwise continue with a prompt