The blackboard

Every FSM/BT agent owns a Blackboard — its private key/value store plus one-shot event triggers. Actions and conditions reach it through ctx.blackboard; it’s how AI state flows between leaves and how transition guards get their values.

registerAction('takeDamage', (ctx) => {
  const hp = (ctx.blackboard.get<number>('health') ?? 100) - 10;
  ctx.blackboard.set('health', hp);
  if (hp <= 0) ctx.blackboard.fire('died');   // a transition keyed on 'died' fires once
});

Method	Description
get<T>(key) / set(key, value)	Read/write a value.
has(key) / delete(key)	Test / remove a key.
fire(trigger)	Fire a one-shot event; a transition keyed on it becomes enabled until taken.
isFired(trigger) / consume(trigger)	Test / clear a trigger.

Blackboard values back the guard comparisons on FSM transitions, and the trigger mechanism is the Unity-style edge event: fired once, consumed by the transition that takes it.