Voice Mail Detection Not Working on Agents with Transfer Nodes on Start

Support Help
1

On an agent with transfer to agent nodes, as well as code or logic split, or variable notes on launch as a splitter, Voice Mail detection fails, and the agent would often times repeat the same things, even though it’s only in voice mail.

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2

Hello @bobbywu042 could you please share the relevant Call ID? This will help us review the issue and investigate it further.

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**call_68c9e10ae3bcdef227e7eb97f80

call_45262ff82481df1ae5f27ff43bb

call_8aa866f31064d72ecb46a10ebe3

call_35f9240aacb53a8ab90f5af3290

call_585fb08f83909724a3f336cef11

There are more. But I hope these calls serve as a good example.

The agent starts on a splitter node, and during the split the intial words of the voice mail detection are being spoken. Which then doesn’t land in the transcript. This causes the agent to missbehave and not treat it as voice mail, but as human spoken. Even with voice mail detection turned on in Retell.**

4

Hey @bobbywu042 Checking it with the team.

Thank You

5

Hello @bobbywu042 Thanks for the detailed report and the sample calls — the pattern reproduces on all sampled calls.

What’s happening:

  • The flow starts on a Logic Split, which auto-transitions in ~10ms into the “Welcome” speech node, so the agent begins speaking essentially at t=0.

  • Voicemail detection needs a clean stretch of callee speech at the moment the agent decides to respond.

Because the agent decides to speak before any callee audio arrives, and the greeting then overlaps that outgoing speech, the runtime classifier doesn’t get a full callee voicemail turn to score — so it doesn’t fire the hangup, even though your voicemailOption and detectionPrompt are configured correctly and the greeting phrases show up in the transcript.

  • Post-call analysis still flags inVoicemail: true on most of these, which confirms they were voicemails — that’s the offline summary, not the runtime detector.

What we’d recommend trying:

  • Add a short Pause Before Speaking / begin-message delay (~2–3s) so the callee’s greeting can land as a complete callee turn before the agent’s first response fires.

Thank You