Check phone numbers against internal or external DNC lists before making outbound calls to ensure compliance.

Do-Not-Call List

The Do-Not-Call (DNC) List tool checks phone numbers against your DNC registry before making outbound calls. This ensures compliance with telecommunications regulations (TCPA, FCC) and prevents calling numbers that have opted out.

How It Works

-> Before outbound call, agent checks the target number
-> Agent calls check_dnc_list with phone_number="+14155551234"
-> Returns "CLEAR" or "BLOCKED"

If BLOCKED:
Agent: "I'm unable to call that number as it's on the Do-Not-Call list."

If CLEAR:
-> Outbound call proceeds normally

Configuration

{
  "dncListEnabled": true,
  "dncListSource": "internal",
  "dncInternalNumbers": ["+14155551111", "+14155552222"],
  "dncCheckMode": "before_call",
  "dncBlockAction": "block",
  "dncApiUrl": ""
}

Setting	Type	Default	Description
`dncListEnabled`	boolean	`false`	Enable DNC checking
`dncListSource`	string	`internal`	Source: `internal` (built-in list) or `api` (external service)
`dncInternalNumbers`	string[]	`[]`	Phone numbers on the internal DNC list
`dncCheckMode`	string	`before_call`	When to check: `before_call` or `always`
`dncBlockAction`	string	`block`	On DNC match: `block` (prevent call) or `warn` (proceed with warning)
`dncApiUrl`	string	—	External DNC API endpoint for `api` source

LLM Tool

Tool name: check_dnc_list

Parameters:
  phone_number: string (phone number to check)

Returns:
  "CLEAR: +14155551234 is not on the Do-Not-Call list. Safe to call."
  "BLOCKED: +14155551234 is on the Do-Not-Call list. This number cannot be called."
  "WARNING: +14155551234 is on the Do-Not-Call list. Proceed with caution."

DNC Sources

Internal List

Maintain your own DNC list directly in the agent configuration. Numbers are compared after stripping formatting.

External API

Query an external DNC compliance service. The API receives a GET request:

GET https://your-dnc-api.com/check?phone=+14155551234

Expected response:

{
  "on_dnc_list": true,
  "blocked": true
}

Example — Create Agent with DNC List

curl -X POST https://api.thinnest.ai/v1/agents \
  -H "Authorization: Bearer $THINNESTAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Outbound Sales Agent",
    "model": "gpt-4o",
    "instructions": "You make outbound sales calls. Before calling any number, check the DNC list first. If the number is blocked, do NOT call it.",
    "voiceEnabled": true,
    "transcriber": { "provider": "deepgram", "model": "nova-2-conversationalai" },
    "voice": { "provider": "deepgram", "voiceId": "aura-2-thalia-en" },
    "dncListEnabled": true,
    "dncListSource": "internal",
    "dncInternalNumbers": ["+14155551111", "+14155552222"],
    "dncCheckMode": "before_call",
    "dncBlockAction": "block"
  }'

Do-Not-Call List

On this page