curl --request POST \
  --url 'https://api.stateset.com/api/v1/negotiations/{id}/counter-offer' \
  --header "Authorization: Bearer $STATESET_API_KEY" \
  --header 'Content-Type: application/json' \
  --data '{
  "amount": "49.00",
  "from_agent_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "message": "Two-person tent, green — replacement for damaged pole set."
}'

{
  "buyer_agent_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "created_at": "2026-08-31T14:22:05Z",
  "currency": "USD",
  "current_offer": "string",
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "max_rounds": 1,
  "offer_count": 1,
  "rounds": 1,
  "seller_agent_id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "status": "pending"
}