## Reaching out first
In most use cases, when the user opens the chat window with your assistant, you will want the assistant to send the first message. Doing this can give the user an idea of what the bot can or can't do and set them up to have a more successful conversation. Some [messaging or voice channels](https://legacy-docs-oss.rasa.com/docs/rasa/next/messaging-and-voice-channels) have existing configuration options to send a payload to the assistant when the user first starts the conversation, but you can also add this option to your [own custom channel](https://legacy-docs-oss.rasa.com/docs/rasa/next/connectors/your-own-website).

Once you've configured your channel to send a payload, you will need to specify how the assistant should react and greet the user. You can either re-use an existing intent's behavior for this, or specify a new intent and rule for this. Below is a guide on how to specify a welcome rule.

### 1. Update the configuration
Since you are using a rule for this behavior, you need to add the [RulePolicy](https://legacy-docs-oss.rasa.com/docs/rasa/next/policies#rule-policy) to your configuration file:

```yaml
policies:
  # other policies
  - name: RulePolicy
```  
### 2. Add a rule
To have the assistant respond to the intent `greet` with a welcome message only at the beginning of a conversation, add the following rule:

```yaml
rules:
- rule: welcome user
  conversation_start: true  # this rule only applies at the beginning of a conversation
  steps:
    - intent: greet
    - action: utter_welcome
```  
### 3. Add a response
Finally, add a response for the `utter_welcome` utter action to your domain:

```yaml
responses:
  utter_welcome:
    - text: Hi there! What can I help you with today?
```

## External Events
Sometimes you want an external device to change the course of an ongoing conversation. For example, if you have a moisture-sensor attached to a Raspberry Pi, you could use it to notify you when a plant needs watering via your assistant.

The examples below are from the [reminderbot example bot](https://github.com/RasaHQ/rasa/blob/main/examples/reminderbot), which includes both reminders and external events.

### 1. Trigger an Intent
To have an event from an external device change the course of an ongoing conversation, you can have the device post to the [`trigger_intent` endpoint](https://legacy-docs-oss.rasa.com/docs/rasa/pages/http-api#operation/triggerConversationIntent) of your conversation. The `trigger_intent` endpoint injects a user intent (possibly with entities) into your conversation. For Rasa, it is as if you entered a message that got classified with that specific intent and entities.

For example, the following post request would inject the intent `EXTERNAL_dry_plant` and the `plant` entity into the conversation with id `user123`:

```bash
curl -H "Content-Type: application/json" -X POST \
 -d '{"name": "EXTERNAL_dry_plant", "entities": {"plant": "Orchid"}}' \
 "http://localhost:5005/conversations/user123/trigger_intent?output_channel=latest"
```  
### 2. Get the Conversation ID
In a real-life scenario, your external device would get the conversation ID from an API or a database. In the dry plant example, you might have a database of plants, the users that water them, and the users' conversation IDs. Your Raspberry Pi would get the conversation ID directly from the database. To try out the reminderbot example locally, you'll need to get the conversation ID manually. See the reminderbot [README](https://github.com/RasaHQ/rasa/blob/main/examples/reminderbot) for more information.

### 3. Add NLU Training Data
In the dry plant example, your Raspberry Pi needs to send a message with the intent `EXTERNAL_dry_plant` to the `trigger_intent` endpoint. This intent will be reserved for use by the Raspberry Pi, so there won't be any NLU training examples for it.

```yaml
domain.yml
intents:
  - EXTERNAL_dry_plant
```  
##### note
You should name intents that come from other devices with the `EXTERNAL_` prefix because it makes it easier to see which intents are expected to come from external devices when working with your training data.

### 4. Update the Domain
To tell the assistant which plant needs watering, you can define an entity that you'll post along with the intent. To be able to use the entity value directly in a response, define a `from_entity` slot mapping for the `plant` slot:

```yaml
domain.yml
entities:
  - plant
slots:
  plant:
    type: text
    influence_conversation: false
    mappings:
      - type: from_entity
        entity: plant
```  
#### 5. Add a Rule
You'll need a rule that tells your assistant how to respond when it receives a message from the Raspberry Pi.

```yaml
rules.yml
rules:
- rule: warn about dry plant
  steps:
    - intent: EXTERNAL_dry_plant
    - action: utter_warn_dry
```  
#### 6. Add a Response
You'll need to define the response text for `utter_warn_dry`:

```yaml
domain.yml
responses:
  utter_warn_dry:
    - text: "Your {plant} needs some water!"
```  
The response will use the value from the slot `plant` to warn about the specific plant that needs watering.

### Try it out
To try out the dry plant notification example, you'll need to start a [CallbackChannel](https://legacy-docs-oss.rasa.com/docs/rasa/next/connectors/your-own-website#callbackinput).

##### caution
External Events and Reminders don't work in request-response channels like the `rest` channel or `rasa shell`. Custom connectors for assistants implementing reminders or external events should be built off of the [CallbackInput channel](https://legacy-docs-oss.rasa.com/docs/rasa/next/connectors/your-own-website#callbackinput) instead of the RestInput channel.

See the [reminderbot README](https://github.com/RasaHQ/rasa/blob/main/examples/reminderbot/README.md) for instructions on how to test your reminders locally.

Run this POST request to simulate the external event, using your conversation ID:

```bash
curl -H "Content-Type: application/json" -X POST -d \
 '{"name": "EXTERNAL_dry_plant", "entities": {"plant": "Orchid"}}'\
 "http://localhost:5005/conversations/user1234/trigger_intent?output_channel=latest"
```

You should see the bot respond in your channel:

Bot: Your Orchid needs some water!

## Reminders
You can have your assistant reach out to the user after a set amount of time by using [Reminders](https://legacy-docs-oss.rasa.com/docs/rasa/next/action-server/events#reminder). The examples below are from the [reminderbot example bot](https://github.com/RasaHQ/rasa/blob/main/examples/reminderbot). You can clone it and follow the instructions in `README` to try out the full version.

### Scheduling Reminders
#### 1. Define a Reminder
To schedule a reminder, you need to define a custom action that returns the `ReminderScheduled` event. For example, the following custom action schedules a reminder for five minutes from now:

```python
actions.py
import datetime
from rasa_sdk.events import ReminderScheduled
from rasa_sdk import Action

class ActionSetReminder(Action):
    """Schedules a reminder, supplied with the last message's entities."""
    def name(self) -> Text:
        return "action_set_reminder"

async def run(self,
                  dispatcher: CollectingDispatcher,
                  tracker: Tracker,
                  domain: Dict[Text, Any],
                  ) -> List[Dict[Text, Any]]:
        dispatcher.utter_message("I will remind you in 5 minutes.")
        date = datetime.datetime.now() + datetime.timedelta(minutes=5)
        entities = tracker.latest_message.get("entities")
        reminder = ReminderScheduled(
            "EXTERNAL_reminder",
            trigger_date_time=date,
            entities=entities,
            name="my_reminder",
            kill_on_user_message=False,
        )
        return [reminder]
```

The first argument for the `ReminderScheduled` event is the reminder's name, in this case, `EXTERNAL_reminder`. The reminder name will be used later as an intent to trigger a reaction to the reminder. Name the reminder name with the `EXTERNAL_` prefix to make it easier to see what's going on in your training data.

You can see that the last messages' `entities` are also passed to the reminder. This allows the action that reacts to the reminder to make use of the entities from the user's scheduling message.

For example, if you want your assistant to remind you to call a friend, you could send it a message like "Remind me to call Paul". If "Paul" is extracted as a `PERSON` entity, the action reacting to the reminder can use it to say "Remember to call Paul!"

#### 2. Add a Rule
To schedule a reminder, add a rule:

```yaml
rules.yml
rules:
- rule: Schedule a reminder
  steps:
    - intent: ask_remind_call
      entities:
      - PERSON
    - action: action_set_reminder
```  
#### 3. Add Training Data
You should add NLU training examples for scheduling the reminder:

```yaml
nlu.yml
nlu:
- intent: ask_remind_call
  examples: |
    - remind me to call John
    - later I have to call Alan
    - Please, remind me to call Vova
    - please remind me to call Tanja
    - I must not forget to call Juste
```  
You should also add it to your domain:

```yaml
domain.yml
intents:
  - ask_remind_call
```  
#### 4. Update your Pipeline
By adding SpacyNLP and SpacyEntityExtractor to your pipeline in config.yml, you won't need to annotate any of the names in your training data, since Spacy has a `PERSON` dimension:

```yaml
config.yml
pipeline:
  # other components
  - name: SpacyNLP
    model: "en_core_web_md"
  - name: SpacyEntityExtractor
    dimensions: ["PERSON"]
```  
### Reacting to Reminders
#### 1. Define a Reaction
The bot reaches out to the user after receiving a POST request to the `trigger_intent` endpoint. Reminders, however, send the request to the right conversation ID automatically after a certain amount of time using the name that you define in the `ReminderScheduled` event.

To define a reaction to the reminder, you only need to write a [rule](https://legacy-docs-oss.rasa.com/docs/rasa/next/rules) that tells the bot what action to take when it receives the reminder intent.
In the call reminder example, you want to use the entities that come with the reminder to be reminded to call specific people, so you need to write a custom action that does that:

```python
actions.py
class ActionReactToReminder(Action):
    """Reminds the user to call someone."""
    def name(self) -> Text:
        return "action_react_to_reminder"

async def run(self,
                  dispatcher: CollectingDispatcher,
                  tracker: Tracker,
                  domain: Dict[Text, Any],
                  ) -> List[Dict[Text, Any]]:
        name = next(tracker.get_slot("PERSON"), "someone")
        dispatcher.utter_message(f"Remember to call {name}!")
        return []
```  
#### 2. Add a Rule
To tell your bot what action to run when a reminder is triggered, add a rule.

```yaml
rules.yml
rules:
- rule: Trigger `action_react_to_reminder` for `EXTERNAL_reminder`
  steps:
    - intent: EXTERNAL_reminder
    - action: action_react_to_reminder
```  
#### 3. Add Training Data
You'll need to define the intent that triggers reacting to the reminder. You don't need to add any training examples, since the intent is reserved for the reminder.

```yaml
domain.yml
intents:
  - intent: EXTERNAL_reminder
```  
### Cancelling Reminders
#### 1. Define an Action that Cancels a Reminder
To cancel a reminder that you've already scheduled, you need a custom action that returns the `ReminderCancelled()` event.
Returning `ReminderCancelled()` cancels all the reminders that are currently scheduled. If you only want to cancel certain reminders, you can specify some parameters by which to narrow down the scheduled reminders:
- `ReminderCancelled(intent="EXTERNAL_greet")` cancels all reminders with intent `EXTERNAL_greet`
- `ReminderCancelled(entities={})` cancels all reminders with the given entities
- `ReminderCancelled("...")` cancels the one unique reminder with the given name “`...`” that you supplied during its creation

For the call reminder example, you can define a custom action `action_forget_reminders` that cancels all reminders:

```python
actions.py
class ForgetReminders(Action):
    """Cancels all reminders."""
    def name(self) -> Text:
        return "action_forget_reminders"

async def run(self,
                  dispatcher: CollectingDispatcher,
                  tracker: Tracker,
                  domain: Dict[Text, Any]
                  ) -> List[Dict[Text, Any]]:
        dispatcher.utter_message(f"Okay, I'll cancel all your reminders.")
        # Cancel all reminders
        return [ReminderCancelled()]
```  
##### caution
All reminders are cancelled whenever you shutdown your Rasa server.

#### 2. Add a Rule
You'll need to add a rule for cancelling a reminder.

```yaml
rules.yml
rules:
- rule: Cancel a reminder
  steps:
    - intent: ask_forget_reminders
    - action: action_forget_reminders
```  
#### 3. Add Training Data
You'll need to define an intent that triggers cancelling the reminder.

```yaml
nlu.yml
nlu:
- intent: ask_forget_reminders
  examples: |
    - Forget about the reminder
    - do not remind me
    - cancel the reminder
    - cancel all reminders please
```  
You should also add it to domain.yml:

```yaml
domain.yml
intents:
  - intent: ask_forget_reminders
```  
### Try it Out
To try out reminders you'll need to start a [CallbackChannel](https://legacy-docs-oss.rasa.com/docs/rasa/next/connectors/your-own-website#callbackinput). You'll also need to start the action server to schedule, react to, and cancel your reminders. See the [reminderbot README](https://github.com/RasaHQ/rasa/blob/main/examples/reminderbot) for details.

Then, if you send the bot a message like `Remind me to call Paul Pots`, you should get a reminder back five minutes later that says `Remember to call Paul Pots!`.
