### Answer Based on the available documentation, there is no explicit mention of Retell AI providing access to the Twilio

X-Twilio-CallToken

header value when using Twilio integration via SIP trunking. [(1) ]() [(2) ]() [(3) ]() When you import a Twilio number via Elastic SIP Trunking, Retell AI captures the

telephony_identifier

which includes the

twilio_call_sid

, but the documentation does not reference access to the

X-Twilio-CallToken

header specifically. [(2) ]() [(4) ]() For custom telephony integrations with Twilio, you would need to verify directly with Retell support whether this specific header is accessible through their API or webhooks, as it's not documented in the current integration guides.

​ To learn more, see the sources I considered: [[1] Twilio](https://docs.retellai.com/deploy/twilio) [[2] Import Phone Number](https://docs.retellai.com/api-references/import-phone-number) [[3] AI in SIP Calling & Telephony Solutions | Retell AI](https://www.retellai.com/blog/integrating-ai-with-sip-trunking-and-modern-telephony) [[4] When using custom telephony (twilio) connected via elastic SIP, I don't receive a twilio_call_sid](https://discord.com/channels/1186424376300679209/1341517149608611840) ​

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