full voice agent 

Totally — you’re talking about a full voice agent that can carry an entire call end-to-end, with the option to “speak over” or inject messages. Think of it like an onion with layers. Here’s what you’d need, from the outside in.

The onion: layers for a call-running voice agent

  1. Telephony access (PSTN/SIP)

  1. Call control / IVR

  • Detects DTMF (“press 1”) and supports barge-in (caller can interrupt).

  • Places/receives calls, starts/stops recordings, bridges to humans.

  1. Low-latency audio I/O

  • 2-way streaming audio with jitter buffers and echo cancellation.

  • Lets the bot talk while listening.

  1. Automatic Speech Recognition (ASR)

  • Real-time transcription with speaker diarization.

  • Domain boosting (“Centrelink”, “superannuation”, member IDs).

  1. Sensitive-data redaction

  • Masks TFNs, card numbers, DOBs in transcripts/recordings.

  • (“Sensitive number provided”)—this is where your voice-over can replace raw audio.

  1. Wake words & event detectors

  • Keyword triggers (“ambulance”, “fraud”, “complaint”) fire webhooks.

  • Those webhooks can inject a message or take over the mic briefly.

  1. Natural-language understanding (NLU)

  • Figures out intent (“payment update”, “ID check”, “hardship”).

  • Extracts entities (CRN, member number, dates).

  1. Dialogue manager / policy brain

  • State machine + LLM planner: decides the next question, verifies answers, handles retries/escapes.

  • Stores context so it doesn’t re-ask things.

  1. Tools & back-end integrations

  1. Authentication & compliance

  • KBA (knowledge-based), one-time codes, voice biometrics (optional).

  • Consent prompts, audit trails, access controls, least privilege.

  1. Text-to-Speech (TTS) / Voice

  • Natural voice with style/tempo control; localised (AU) pronunciation.

  • Optional voice clone or a neutral AU voice to avoid uncanny valley.

  1. Safety, escalation, and human-handover

  • Confidence thresholds, profanity/abuse filters, emergency detection.

  • Instant handoff to a human with full context + transcript.

  • “Push-to-mute” the agent when a human takes over, or do brief agent overrides.

How it runs a whole call (typical flow)

  1. Caller dials → Telephony answers → starts ASR + TTS streaming.

  2. Bot greets, collects reason + ID → NLU extracts details.

  3. Policy brain decides: verify identity → hit back-end via secure API.

  4. If keywords fire (e.g., “lost card”, “ambulance”, “threat”), a webhook injects a mandated line or takes priority (“Your card is now blocked”).

  5. Bot confirms status/next steps → offers SMS/email follow-up (via webhook).

  6. Any low confidence, distress, or regulatory trigger → handoff to human with transcript + key fields; agent speaks, bot goes silent or becomes agent assist (notes, suggested replies).

  7. Wrap-up: case notes, redacted transcript, analytics.

Where “voice-over/override” actually happens

  • During capture: sensitive spans are replaced in the recording (“[redacted TFN]”), while the live agent still hears the real number.

  • During playback: system ducks the human channel to play a standard line (“Stay on the line, reference ID sent”).

  • During policy events: webhook triggers an interrupt message with higher priority than live speech (like the 000-style dispatch update).


checklist (to make this real)

  • Pick a carrier (SIP/PSTN) and enable audio streaming.

  • ASR with domain boost + live redaction.

  • Dialog manager (LLM + rules) with clear handoff thresholds.

  • Back-end connectors (read-only first; then write ops with audit).

  • Webhook bus for: keyword events, compliance inserts, status pings.

  • TTS voice localised for AU; test for caller trust (don’t over-clone).

  • Barge-in + latency target: <300–500 ms end-to-end.

  • Guardrails: consent, logging, rate limits, abuse/emergency routes.

  • Fail-safes: if anything is shaky, transfer to human instantly.


About “same-sounding voices”

Multinationals often reuse the same TTS voices. You can:


  • Choose an AU English model, tweak prosody and pronunciation (suburb names, agencies).

  • Add light variation (pace, warmth, micro-pauses) to avoid that “factory voice” vibe.

  • Keep phrases that must be identical (legal lines), but personalise everything else

If you want, I can sketch a reference architecture diagram or give you sample call flows (prompts + webhook payloads) for a Services-Australia-style “payment status” line and an “urgent fraud lock” line.


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