Hi Team,I'm seeing a persistent issue where retell_llm_dynamic_variables ... Retell AI #❓・ai-evy-support

Hi Team,I'm seeing a persistent issue where retell...

Thomas

12/19/2025, 5:11 AM

@AI Evy Hi Team, I'm seeing a persistent issue where retell_llm_dynamic_variables sent via an Inbound Webhook are received in the logs but fail to hydrate into the call session. The Setup: Inbound Webhook (Make.com): Returns Status 200 OK with: { "call_inbound": { "retell_llm_dynamic_variables": { "spam_flag": "yes" } } } The Result: The Developer logs show the variable is received perfectly. The Proof it's a Bug: I placed a Logic Split node 1 minute into the call (to rule out any race conditions/latency). Even then, the Logic Split followed the Else path, ignoring the yes value from the webhook. Important Details: This happens even with and without global default values set. Using Equation Mode logic split (using the = dropdown). spam_flag = yes. Verified Make.com is sending a string "yes". Why would the system "Accept" the variables in the log but fail to map them to the session context for the Logic Split to use? Call ID: call_399788d52942ebb9f8dfc262df8 Agent ID: agent_13db7934ab9f196d81c535f4d1

AI Evy

12/19/2025, 5:11 AM

Thanks for tagging me @Thomas. I'll look through relevant sources and get back to you shortly.

AI Evy

12/19/2025, 5:11 AM

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

AI Evy

12/19/2025, 5:11 AM

To learn more, see the sources I considered: [[1] Inbound webhook](https://docs.retellai.com/features/inbound-call-webhook) [[2] Dynamic Variables](https://docs.retellai.com/build/dynamic-variables) [[3] {{variable}} / Logic Split Node Issue](https://discord.com/channels/1186424376300679209/1417167639524151441)

AI Evy

12/19/2025, 5:11 AM

### Answer Based on your setup, there's a key issue with your webhook response structure. The inbound webhook expects dynamic variables under the key

dynamic_variables

, not

retell_llm_dynamic_variables

. [(1) ]() Your current payload:

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json
{ "call_inbound": { "retell_llm_dynamic_variables": { "spam_flag": "yes" } } }

Should be:

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json
{
  "call_inbound": {
    "dynamic_variables": {
      "spam_flag": "yes"
    }
  }
}

The

retell_llm_dynamic_variables

field is used when creating outbound calls via the API (like [Create Phone Call]() ) , but for inbound webhook responses, the correct field is

dynamic_variables

. [(2) ]() , [(1) ]() Additionally, regarding your Logic Split node—there's a known behavior where variables from webhook responses may not automatically populate for equation-based conditions. You may need to use Response Variables in a custom function node to explicitly set the variable value before the Logic Split can evaluate it correctly. [(3) ]() Try updating your webhook response to use

dynamic_variables

and see if that resolves the hydration issue.

Thomas

12/19/2025, 2:14 PM

@User Update: I’ve updated my webhook payload to use dynamic_variables instead of retell_llm_dynamic_variables. I’m now trying to implement the fix for the "Logic Split" hydration issue mentioned above. Could someone clarify the best way to use a Custom Function Node to explicitly set this variable so the logic can evaluate it correctly? (Optional: Here is a Call ID for a test I just ran with the updated payload: call_5f8d7fab1de5ce0ed7fa4536ad7

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