By default, the conversation has information about the current date and time in the receiver’s timezone.

Default variables

By default, the following variables and information are always available in the conversation context.

namedescription
agent_idThis is the id of the agent
execution_idThis is the unique id of the bolna conversation or the call
call_sidThis is the unique id of the phone call belonging to telephony providers like Twilio, Plivo, Vonage, etc.

You may use the above information to pass useful info into your systems or use them in the function calls or prompts.

Example using default variables

For example, adding the below content in the prompt using the above default variables will automatically fill in their values.


This is your agent Sam. Please have a frienly conversation with the customer.

Please note:
The agent has a unique id which is "{agent_id}".
The call's unique id is "{call_sid}".

The above prompt content computes to and is fed as:


This is your agent Sam. Please have a frienly conversation with the customer.

Please note:
The agent has a unique id which is "4a8135ce-94fc-4a80-9a33-140fe1ed8ff5".
The call's unique id is "PXNEJUFEWUEWHVEWHQFEWJ".


Custom variables

Apart from the default variables, you can write your own variables and pass it into the prompt.

Any content written between {} in the prompt becomes a variable.

For example, adding the below content in the prompt will dynamically fill in the values.

Example using custom variables

This is your agent Sam speaking.

May I confirm if your name is {customer_name} and you called us on 
{last_contacted_on} to enquire about your order item {product_name}.

Use the call's id which is {call_sid} to automatically transfer the call to a human when the user asks.

You can now pass these values while placing the call:

curl --request POST \
  --url https://api.bolna.dev/call \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "agent_id": "123e4567-e89b-12d3-a456-426655440000",
  "recipient_phone_number": "+10123456789",
  "from_phone_number": "+1987654007",
  "user_data": {
    "customer_name": "Caroline",
    "last_contacted_on": "4th August",
    "product_name": "Pearl shampoo bar"
  }
}'

The above prompt content computes to and is fed as (call_sid being the default variable gets injected automatically by default):


This is your agent Sam speaking.

May I confirm if your name is Caroline and you called us on
4th August to enquire about your order item Pearl shampoo bar.

Use the call's id which is PDFHNEWFHVUWEHC to automatically transfer the call to a human when the user asks.