docs: clarify json field behavior

README.md

@@ -125,6 +125,22 @@ Importante:
 - `Mega Client` usa identificadores publicos como `inbox_identifier`, `contact_identifier`, and `conversation_id`
 - `CSAT Survey` usa uma rota publica `conversation_uuid` fora do padrao `/public/api/v1/inboxes/*`
 
+## Campos JSON
+
+Os campos do tipo `json` nos nodes `Mega`, `Mega Client` e `Mega Platform` esperam objetos JSON validos quando o payload do endpoint for estruturado. Exemplos de valor para o proprio campo:
+
+```json
+{"name":"Maria"}
+```
+
+ou:
+
+```json
+{"crm_id":"123"}
+```
+
+Quando o campo estiver vazio, o node envia `{}` ou omite o atributo opcional conforme o endpoint, evitando enviar strings como `"{}"` para a API.
+
 
 ## Operacoes
 
@@ -1087,8 +1103,7 @@ When attachments are provided in `Create and Send Message`, the node creates the
 - Multiple attachments are supported in the same message
 - Message text becomes optional when at least one attachment is provided
 - Files are sent as `attachments[]` in `multipart/form-data`
-
-This first version supports one message only and does not expose advanced message payload fields such as `content_type`, `template_params`, `campaign_id`, or `content_attributes`.
+- `Create a new message` also exposes optional advanced payload fields such as `Content Type`, `Content Attributes`, `Campaign ID`, and `Template Params`
 
 ## Validacao local