### Answer Based on the available documentation, you can override agent settings before a call starts, but not during an active call. [(1) ]() For outbound calls, you can pass overrides when using

createPhoneCall

or

register-phone-call

- these overrides apply only to that specific call. For inbound calls, you handle overrides in your inbound webhook by returning them in the response. The

agent_override

object supports partial agent settings including

voice_id

,

voice_model

,

language

, and other configuration options. [(2) ]() However, there's no documented method to change agent settings during an active call. The overrides must be set when the call is initiated or registered. [(1) ]() If you need language-specific settings, you could: - Create separate agents for each language - Use dynamic variables to customize behavior based on language [(3) ]() - Set the appropriate overrides before the call starts based on expected language [(2) ]()

​ To learn more, see the sources I considered: [[1] Override agent's configurations before making a call.](https://discord.com/channels/1186424376300679209/1315610729172434945) [[2] Inbound webhook](https://docs.retellai.com/features/inbound-call-webhook) [[3] Dynamic Variables](https://docs.retellai.com/build/dynamic-variables) ​

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

### Answer I don't have information about a

custom_attributes

parameter in the Create Call or Update Call APIs based on the available sources. The sources show a

metadata

parameter instead, which serves as an arbitrary object for storage purposes. [(1) ]() [(2) ]() Here's an example of using

metadata

in the Create Phone Call API: [(1) ]()

javascript
import Retell from 'retell-sdk';
const client = new Retell({
 apiKey: 'YOUR_RETELL_API_KEY',
}) ;
const phoneCallResponse = await client.call.createPhoneCall({
 from_number: '+14157774444',
 to_number: '+12137774445',
}) ;

The

metadata

object allows you to store any arbitrary data like internal customer IDs associated with the call. It's not used for processing but can be retrieved later from the call object. [(1) ]() [(2) ]() If you're looking for a different parameter or if

custom_attributes

is mentioned in other documentation, I'd be happy to help if you can provide more context about where you encountered this parameter.

​ To learn more, see the sources I considered: [[1] Create Phone Call](https://docs.retellai.com/api-references/create-phone-call) [[2] Register Phone Call](https://docs.retellai.com/api-references/register-phone-call) ​

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