Voicemail detection: test classification and message delivery separately

Voicemail detection estimates whether a call reached a person or an answering system. It can be wrong. A message played after a machine classification may also start too early, be cut off or never be recorded. Classification and delivery need separate evidence.

Understand the error types

A false machine result can cause a real person to hear a voicemail message or be disconnected. A false human result can leave an assistant talking to a greeting. An unknown result needs an explicit policy rather than being silently counted as a person.

Carrier implementations differ. For example, Twilio's AMD documentation describes tunable speech/silence detection, unknown results and accuracy trade-offs. That provider capability is not proof that Burki's LiveKit route uses the same mechanism.

Check the selected runtime

Burki's cascade campaign voicemail path uses configured policy and transcript-based detection with one-shot message handling. GPT Live admission currently rejects configurations that require that voicemail behavior. Do not assume changing the voice model preserves the feature.

A browser conversation cannot validate carrier voicemail timing or recording. Test the actual permitted telephone configuration with controlled numbers before using it in a campaign.

Define the policy before the call

Decide whether an observed voicemail should end the attempt or receive an approved message, what information the message may contain and how an uncertain detection is handled. Avoid sensitive information that could be heard by someone other than the intended recipient.

Message permission, contact restrictions and retry limits remain relevant. Detection is not an exemption from the rules governing the call or message.

Use a small test matrix

Include a short greeting, a long greeting, silence, a human who says a voicemail-like phrase and a person who answers slowly. Record the classification, time spent, actual playback and whether the message was received intact. Inspect hangup and settlement afterward.

Do not retry immediately just because delivery is uncertain. Determine what happened and apply the approved contact policy. Track incorrect human classifications and incomplete messages alongside successful delivery; a low detection time alone is not a quality result.

Use the campaign guide to keep voicemail behavior within a bounded, accepted execution path.