Verify caller identity using voiceprint analysis — internal phrase matching or external providers like Pindrop and Nuance.

Voice Biometrics

The Voice Biometrics tool verifies caller identity using voiceprint analysis. The agent asks the caller to speak a specific phrase, then compares it against stored voiceprint data. Supports both internal phrase matching and external providers (Pindrop, Nuance).

How It Works

Agent: "For security, please say the phrase: 'My voice is my password.'"
Caller: "My voice is my password."
-> Agent calls verify_voice_identity with the spoken phrase
-> Voiceprint comparison runs (internal or external API)
Agent: "Voice identity verified successfully. How can I help you today?"

Configuration

{
  "voiceBiometricsEnabled": true,
  "voiceBiometricsProvider": "internal",
  "voiceBiometricsAction": "verify",
  "voiceBiometricsEnrollPhrase": "My voice is my password",
  "voiceBiometricsConfidenceThreshold": 0.7,
  "voiceBiometricsFailAction": "end_call",
  "voiceBiometricsTransferTarget": "+14155551234"
}

Setting	Type	Default	Description
`voiceBiometricsEnabled`	boolean	`false`	Enable voice biometrics
`voiceBiometricsProvider`	string	`internal`	Provider: `internal`, `pindrop`, `nuance`, or custom
`voiceBiometricsAction`	string	`verify`	`verify` (existing users) or `enroll_and_verify` (new + existing)
`voiceBiometricsEnrollPhrase`	string	—	Phrase the caller must speak
`voiceBiometricsConfidenceThreshold`	float	`0.7`	Minimum confidence for verification (0.0-1.0)
`voiceBiometricsFailAction`	string	`end_call`	On failure: `end_call`, `transfer`, `continue`
`voiceBiometricsTransferTarget`	string	—	Transfer number on failure

External Provider Settings

For external providers (Pindrop, Nuance, etc.):

Setting	Type	Description
`voiceBiometricsApiKey`	string	API key for the biometrics provider
`voiceBiometricsApiSecret`	string	API secret
`voiceBiometricsApiEndpoint`	string	Provider API endpoint URL

LLM Tool

Tool name: verify_voice_identity

Parameters:
  spoken_phrase: string (what the caller said)

Returns:
  Success: "Voice identity verified successfully (confidence: 85%). The caller is authenticated."
  Failure: "Voice verification failed (confidence: 40%, threshold: 70%). The caller could not be authenticated."

Providers

Provider	How It Works
`internal`	Fuzzy word matching against the enrollment phrase. Good for demos and simple use cases.
`pindrop`	External API call to Pindrop's voiceprint service
`nuance`	External API call to Nuance's voice biometrics
Custom	Any provider with a REST API

Failure Actions

Action	Behavior
`end_call`	Agent apologizes and ends the call
`transfer`	Agent transfers to the configured number
`continue`	Agent continues with limited access (no sensitive operations)

Example — Create Agent with Voice Biometrics

curl -X POST https://api.thinnest.ai/v1/agents \
  -H "Authorization: Bearer $THINNESTAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Secure Banking Agent",
    "model": "gpt-4o",
    "instructions": "You are a secure banking agent. Before accessing any account information, verify the caller identity using voice biometrics. Ask them to say the enrollment phrase.",
    "voiceEnabled": true,
    "transcriber": { "provider": "deepgram", "model": "nova-2-conversationalai" },
    "voice": { "provider": "deepgram", "voiceId": "aura-2-thalia-en" },
    "voiceBiometricsEnabled": true,
    "voiceBiometricsProvider": "internal",
    "voiceBiometricsAction": "verify",
    "voiceBiometricsEnrollPhrase": "My voice is my password",
    "voiceBiometricsConfidenceThreshold": 0.7,
    "voiceBiometricsFailAction": "transfer",
    "voiceBiometricsTransferTarget": "+14155551234"
  }'

Voice Biometrics

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