curl --request POST \
  --url https://prod.featherhq.com/api/v1/email/threads \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "agentVersionId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "toEmail": "jsmith@example.com",
  "subject": "<string>",
  "firstMessage": "<string>",
  "leadId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "variables": {},
  "metadata": {}
}
'

{
  "thread": {
    "id": "<string>",
    "agentId": "<string>",
    "agentVersionId": "<string>",
    "organizationId": "<string>",
    "emailDomainId": "<string>",
    "fromEmail": "<string>",
    "fromName": "<string>",
    "toEmail": "<string>",
    "subject": "<string>",
    "leadId": "<string>",
    "isActive": true,
    "createdAt": "<string>"
  }
}