### Answer Yes, you can configure the SMS destination in the app's tool/node configuration. By default, the SMS is sent to the caller's number, but you can also choose to send to a different number, either a static number or a dynamic variable (e.g.

{{customer_phone}}

) [(1) ]() [(2) ]() . This applies for both the Send SMS tool in single/multi-prompt agents [(1) ]() and the SMS Node in Conversation Flow agents [(2) ]() . There's no SDK-level parameter documented for configuring the destination of this in-call SMS feature specifically — the destination configuration described in the sources is done through the tool/node setup in the app [(1) ]() [(2) ]() . Note this is distinct from the Create Outbound SMS API, which uses

to_number

and

from_number

fields to start a new SMS chat conversation rather than configure an in-call SMS destination [(3) ]() :

javascript
const chatResponse = await client.chat.createSMSChat({
 from_number: '+12137771234',
 to_number: '+14155551234',
}) ;
console.log(chatResponse.agent_id) ;

​ To learn more, see the sources I considered: [[1] Send SMS](https://docs.retellai.com/build/single-multi-prompt/send-sms) [[2] SMS Node](https://docs.retellai.com/build/conversation-flow/sms-node) [[3] Create Outbound SMS](https://docs.retellai.com/api-references/create-sms-chat) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer Correct, there's no documented API parameter for configuring the in-call SMS destination for the Send SMS tool or SMS Node. That destination (caller's number, a static number, or a dynamic variable like

{{customer_phone}}

) is configured through the tool/node setup in the app itself [(1) ]() [(2) ]() . The `to_number`/`from_number` fields you see in the API are for a separate feature — the Create Outbound SMS endpoint, which starts a brand-new SMS chat conversation, not an in-call SMS sent mid-phone-call:

javascript
const chatResponse = await client.chat.createSMSChat({
 from_number: '+12137771234',
 to_number: '+14155551234',
}) ;
console.log(chatResponse.agent_id) ;

[(3) ]()

​ To learn more, see the sources I considered: [[1] SMS Node](https://docs.retellai.com/build/conversation-flow/sms-node) [[2] Send SMS](https://docs.retellai.com/build/single-multi-prompt/send-sms) [[3] Create Outbound SMS](https://docs.retellai.com/api-references/create-sms-chat) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.