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Overview

Use dynamic variables in the system prompt or any message in the dashboard with double curly braces (e.g., {{name}}).

To set values, make a phone call request through the API and set assistantOverrides. You cannot set variable values directly in the dashboard.

For example, set the assistant’s first message to “Hello, {{name}}!” and assign name to Akash by passing assistantOverrides with variableValues:

{
  "variableValues": {
    "name": "Akash"
  }
}

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Using dynamic variables in a phone call

1

Prepare Your Request

Create a JSON payload with these key-value pairs:

  • assistantId: Replace "your-assistant-id" with your assistant’s actual ID.
  • assistantOverride: Customize your assistant’s behavior.
    • variableValues: Include dynamic variables in the format { "variableName": "variableValue" }. Example: { "name": "John" }.
  • customer: Represent the call recipient.
    • number: Replace "+1xxxxxxxxxx" with the recipient’s phone number (E.164 format).
  • phoneNumberId: Replace "your-phone-id" with your registered phone number’s ID. Find it on the Phone number page.
2

Send the Request

Send the JSON payload to the /call/phone endpoint using your preferred method (e.g., HTTP POST request).

{
  "assistantId": "your-assistant-id",
  "assistantOverrides": {
    "variableValues": {
      "name": "Akash"
    }
  },
  "customer": {
    "number": "+91xxxxxxxxx"
  },
  "phoneNumberId": "your-phone-id"
}

Ensure {{variableName}} is included in all prompts where needed.

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Default Variables

These variables are automatically filled based on the current (UTC) time, so you don’t need to set them manually in variableValues:

VariableDescriptionExample
{{now}}Current date and time (UTC)Jan 1, 2024 12:00 PM
{{date}}Current date (UTC)Jan 1, 2024
{{time}}Current time (UTC)12:00 PM
{{month}}Current month (UTC)January
{{day}}Current day of month (UTC)1
{{year}}Current year (UTC)2024
{{customer.number}}Customer’s phone number+1xxxxxxxxxx
{{customer.X}}Any other customer property

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Advanced date and time usage

You can use advanced date and time formatting in any prompt or message that supports dynamic variables in the dashboard or API. We use LiquidJS for formatting - see their docs for details.

Format a date or time using the LiquidJS date filter:

{{"now" | date: "%A, %B %d, %Y, %I:%M %p", "America/Los_Angeles"}}

Outputs: Monday, January 01, 2024, 03:45 PM

Examples:

  • 24-hour time: 
    {{"now" | date: "%H:%M", "Europe/London"}}
    → 17:30
  • Day of week: 
    {{"now" | date: "%A"}}
    → Tuesday
  • With customer number: 
    Hello, your number is {{customer.number}} and the time is {{"now" | date: "%I:%M %p", "America/New_York"}}

Common formats:

Format StringOutputDescription
%Y-%m-%d2024-01-01Year-Month-Day
%I:%M %p03:45 PMHour:Minute AM/PM
%H:%M15:4524-hour time
%AMondayDay of week
%b %d, %YJan 01, 2024Abbrev. Month Day

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Using dynamic variables in the dashboard

To use dynamic variables in the dashboard, include them in your prompts or messages using double curly braces. For example:

Hello, {{name}}!

When you start a call, you must provide a value for each variable (like name) in the call configuration or via the API/SDK.

Always use double curly braces ({{variableName}}) to reference dynamic variables in your prompts and messages.