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Conversational & voice AI

Speech, business context and a reliable handoff.

Connect conversational input to verified account context and scoped actions. For voice, engineer turn detection, interruptible audio and escalation so the system preserves what was heard, attempted and still unresolved.

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System architectureStacklane engineering
Listen → Understand → Resolve → Respond
The engineering problem

A useful voice agent has to listen, too.

Callers pause, correct themselves and ask for a person. The system must stop obsolete playback, preserve conversation state and avoid claiming that a transfer or business action succeeded prematurely.

Example integration surface
  • SIP / WebRTC
  • LiveKit
  • Order API
  • Support queue

Inside the system

An order question across four conversation stages.

A synthetic delayed-order call combines streaming speech, account verification, an order lookup and a contextual handoff.

Execution model01 / 04
TURN STATE · AUDIO PLAYBACK · CONTEXT-PRESERVING HANDOFFCallerAgentToolsDetect end of turnSpeech + silence policyInterruptedQueue clearedPlayback statePlayed ≠ generatedIdentity → order lookupVerify caller before reading dataTransfer requestQueue + agent availabilityHandoff packet: intent, verified context, tool resultsKeep the caller informed until the receiving agent actually answers.

Swipe to inspect the full diagram →

turn.v1Example record
channel
Voice
turn_state
Caller speaking
audio_policy
Stop on interruption

Follow the architecture as you scroll, or select a layer.

01

Capture speech and turn boundaries

Receive the audio stream and detect when the caller starts and finishes speaking. Distinguish meaningful interruptions from background sound or short acknowledgments.

Input
Caller audio and session events
Transform
Detect speech, turns and interruptions
Output
Committed turn with timing events
Turn detectionInterruptible playbackSession-scoped state
02

Resolve intent and identity

Interpret the request, confirm ambiguous identifiers and complete the configured identity check before reading account-specific information. Verification is enforced by application code.

Input
Committed utterance and session context
Transform
Resolve intent; enforce identity check
Output
Verified intent and permitted record scope
Identity before account lookupAmbiguity requires clarificationCaller ID is not authentication
03

Read evidence and select an action

Read the order and relevant policy through scoped tools. Draft an answer or escalation packet; unsupported requests and failed tools remain unresolved.

Input
Verified intent and approved knowledge
Transform
Read order; prepare answer or escalation
Output
Grounded response and attempted-action record
Scoped toolsConfirmation for supported writesBounded tool timeouts
04

Speak or transfer with context

Stream the answer while tracking actual playback. If a person is needed, provide the conversation and tool outcomes before connecting; return to the caller when the transfer cannot complete.

Input
Response, playback state and escalation context
Transform
Play, interrupt or coordinate warm transfer
Output
Heard response or confirmed human connection
Clear obsolete queued audioPreserve heard conversationConfirm transfer connection

Inspect the behavior

Follow the conversation through an interruption.

A silent, simulated conversation shows a grounded answer, an interruption and an unavailable transfer destination.

Illustrative system · Synthetic inputs
Input

After the configured identity check, the caller asks why ORD-7324 is delayed. The order API confirms carrier pickup is pending.

Listen: passed
Understand: passed
Resolve: passed
Respond: passed
System decision

The answer matches the account record.

The simulated agent explains that pickup is pending. It does not invent a delivery promise or change the order. Playback completion is distinct from text generation.

order
ORD-7324
verified_status
Pickup pending
business_action
Read only

Verification specification

Define what passes.
Inspect what fails.

We turn expected behavior into repeatable tests and operating controls. Acceptance thresholds are agreed for your workflow, data, and the consequences of an error.

System propertyVerification methodRelease / operating condition

01Account-access boundary

Replay failed verification and ambiguous order identifiers.

No account-specific lookup until identity and scope pass.

02Interruption and turn quality

Test corrections, pauses, acknowledgments and overlapping speech.

Stop obsolete playback and preserve the heard conversation.

03Tool and transfer recovery

Inject order-API timeouts and unavailable support destinations.

Keep failures visible; confirm actions and connections before success.

The handover

Engineering you
can build on.

A defined implementation, reviewable evidence, and an operating model your team can own.

How we work

Conversation and tool specification

Supported intents, identity checks, scoped actions and escalation states.

Voice or chat integration

Streaming, turn handling, playback tracking and contextual transfer.

Conversation evaluation and telemetry

Scenario replays, task outcomes, measured latency breakdowns and session traces.

Architecture decisions

Questions that
shape the build.

How do you control what the agent can do?

Each tool has an explicit scope and authorization checks in application code. We define which actions require identity verification, confirmation, or approval. The model can propose an action; the execution layer enforces the permitted operation.

How do you evaluate a voice agent?

We test task completion alongside interruptions, ambiguous speech, missing records, tool failures, and transfers. For voice, end-to-end latency and turn-taking are part of acceptance criteria. Recording and retention settings are defined with the client for the deployment.

Technical referencesLiveKit turn detection and interruptions Twilio playback marks and audio-buffer clearing LiveKit agent-assisted warm transfer
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