The case summary can be up to 4,000 characters long and can be formatted with the rich text editor. The first 125 characters are shown in the case summary widget, without formatting.
Furthermore, there’s no way to increase the word limit. The maximum is 4,000, and it is fixed at 4,000.
📌 Note: To access the guide, you'll need to log in to the Customer Success Portal.
For further details, please refer to page 341 of the Mosaic guide, under the section Working with Case Summaries.