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Each scenario’s state can be activated by any of configured activator - a rule that tries to handle the user’s request and find an appropriate state of scenario to execute it’s action block. Activators function is a builder function of scenario that can be used to define which activators could activate the state.

How it works

state("launch") {
    activators {

    action {

Here is a top-level state “launch” that can be activated by Alexa’s LAUNCH event, Dialogflow’s WELCOME intent or regular expression that matches any input with “/start” character sequence.


By default activators will activate the state only if the parent state was activated previously. You can configure activators to be global - in this case the state can be activated by these activators as it was a top-level.

state("main") {
    state("inner") {
        activators {
        globalActivators {

In the example above state “inner” could be activated by two different activators - intent activator with “some_intent” intent’s name and event activator with “activate_inner_state” event’s name. Once the intent activator could activate this state only in case the parent “main” state was activated previously, the event activator is a global and can activate “inner” state from everywhere.


Activators function accepts an optional state path from where it is available. It means that you can “override” a parent’s state path to make a state available from some other state.

state("main") {
    state("inner") {
        activators(fromState = "/other") {

In the example above “inner” state can be activated once a dialogue is in state “/other”. You can think about this as a mix-in feature.

Available activators

JAICF provides a set of available activators that can be used in your scenarios.

  • intent to activate state by some particular intent recognised by NLU service
  • anyIntent to activate state by any intent
  • event to activate state by some specific event received from the channel
  • anyEvent to activate state by any event
  • regex to activate state by matching the user’s input with some regular expression
  • catchAll to activate state by ant user’s input

Writing custom activation rules

It’s easy to implement your own activation rule inside scenario. See the example how to create an intent activator which activates all intens with common prefix:

// your activation rule
class IntentByPrefixActivationRule(
    private val commonPrefix: String
) : IntentActivationRule({
    it.intent.startsWith(commonPrefix) // your core activation logic

// your extension method which registers an activation rule
fun ActivationRulesBuilder.intentByPrefix(commonPrefix: String) = rule(IntentByPrefixActivationRule(commonPrefix))

And here is its usage example:

activators {

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