### Answer Based on the available documentation for the Update Voice Agent API, the response example shows fields like

response_engine

,

voice_id

,

webhook_url

, and various agent configuration options, but custom functions are not explicitly shown as a field in the update-agent endpoint. [(1) ]() Custom functions appear to be configured through the dashboard interface or as part of the LLM/response engine configuration rather than directly via the update-agent API payload. [(2) ]() [(3) ]() I don't have explicit documentation confirming whether custom functions can be attached or updated via the update-agent API, or what the payload shape would be for that. For a definitive answer, I'd suggest: - Checking the full API reference at [Update Voice Agent]() - Reaching out via [Contact Sales]() or the [Retell AI GitHub]() Would you like me to try providing a general answer based on my broader knowledge, or is there another aspect of the custom function configuration I can help clarify?

​ To learn more, see the sources I considered: [[1] Update Voice Agent](https://docs.retellai.com/api-references/update-agent) [[2] Custom Function](https://docs.retellai.com/build/conversation-flow/custom-function) [[3] Integrate any system with custom function](https://docs.retellai.com/build/single-multi-prompt/custom-function) ​

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

### Answer --- I don't have documentation in the available sources that explicitly describes an API endpoint for duplicating an existing agent, or whether functions would be included when doing so. The sources I have cover the Update Voice Agent API, which allows modifying existing agent configurations like

response_engine

,

voice_id

,

webhook_url

, and various settings, but doesn't show a duplicate/clone operation. [(1) ]() For a definitive answer on agent duplication via API and whether custom functions carry over, I'd recommend: - Visiting [Contact Sales]() - Checking [) Would you like me to try providing a general answer based on my broader knowledge?

​ To learn more, see the sources I considered: [[1] Update Voice Agent](https://docs.retellai.com/api-references/update-agent) ​

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