End Call

The End Call tool lets your voice agent programmatically hang up a call based on conversation context. Instead of waiting for the caller to disconnect, your agent can end the call gracefully after resolving the issue, completing a booking, or when the conversation reaches a natural conclusion.

When to Use

The caller’s issue is resolved and they say “goodbye” or “thank you”
The agent has completed its task (e.g., appointment booked, order status provided)
The caller is unresponsive or silent for too long
The conversation reaches a predefined time limit
The caller is abusive or violating usage policies

Configuration

Via the Dashboard

Open your agent and scroll to Voice Settings.
Enable End Call.
Configure the options:

Setting	Description	Default
Farewell message	What the agent says before hanging up	”Thank you for calling. Goodbye!”
Silence timeout	Seconds of silence before auto-ending	30 seconds
Max call duration	Maximum call length before auto-ending	None (unlimited)
Post-call webhook	URL to notify after the call ends	None

Click Save.

Via the API

curl -X PATCH https://api.thinnest.ai/agents/agent_abc123 \
  -H "Authorization: Bearer $THINNESTAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "voice_tools": {
      "end_call": {
        "enabled": true,
        "farewell_message": "Thanks for calling Acme Corp! Have a great day.",
        "silence_timeout_seconds": 30,
        "max_duration_seconds": 600,
        "post_call_webhook": "https://your-app.com/webhooks/call-ended"
      }
    }
  }'

System Prompt Guidance

Add instructions to your agent’s system prompt to control when it should end calls:

When the caller's issue is resolved and they confirm they don't need anything else,
say a brief goodbye and end the call. If the caller says "goodbye", "that's all",
or "thanks, bye", end the call immediately after a brief farewell.

Do not end the call if the caller still has questions or seems uncertain.

Post-Call Webhook

When a call ends, thinnestAI sends a webhook to your configured URL with the call summary:

{
  "event": "call.ended",
  "call_id": "call_xyz789",
  "agent_id": "agent_abc123",
  "duration_seconds": 145,
  "end_reason": "agent_ended",
  "transcript_url": "https://api.thinnest.ai/calls/call_xyz789/transcript",
  "recording_url": "https://api.thinnest.ai/calls/call_xyz789/recording"
}

The end_reason field indicates why the call ended:

Reason	Description
`agent_ended`	Agent triggered End Call
`caller_hangup`	Caller disconnected
`silence_timeout`	No speech detected for the configured timeout
`max_duration`	Call reached the maximum duration limit
`error`	Technical error during the call

Voice Tools Overview Transfer Call

Introduction

Getting Started

Voice Agents

Agent Capabilities

Channels

Quality & Oversight

Platform

End Call

End Call

When to Use

Configuration

Via the Dashboard

Via the API

System Prompt Guidance

Post-Call Webhook

​End Call

​When to Use

​Configuration

​Via the Dashboard

​Via the API

​System Prompt Guidance

​Post-Call Webhook

End Call

When to Use

Configuration

Via the Dashboard

Via the API

System Prompt Guidance

Post-Call Webhook