curl "https://app.talkover.ai/api/v1/agents/agent-uuid/active-call/%2B15551234567" \
  -H "Authorization: Bearer talq_your_environment_token_here"

{
  "success": true,
  "data": [
    {
      "id": "call-uuid-1",
      "agent_id": "agent-uuid",
      "to": "+15551234567",
      "status": "answered",
      "started_at": "2024-01-15T11:00:00Z",
      "duration_seconds": 42
    }
  ]
}

{
  "success": false,
  "message": "No active call found for this phone number"
}