I've tried prompting models like ChatGPT, Cursor, and Deepseek to summarize or refine text to fit within 90–160 characters, yet they frequently exceed the limit. Even after I point this out and ask for a shorter version, they still tend to go over the range. As a result, I created a simple tool to precisely count characters. What kind of prompt should I use to ensure AI reliably generates text within the desired range?