Update README: Change output format to JSON structure

README.md

@@ -46,10 +46,12 @@ Remember: Write as if you're chatting with an old friend! Don't start with obvio
 CRITICAL: The email MUST feel like a casual conversation between friends! Write as if you're excitedly telling a friend about something cool you found. Completely avoid any marketing language or sales pitch tone. The reader should feel like they're getting a genuine personal message, not a promotional email.
 
 IMPORTANT: 
-- Please output ONLY the email content itself in English
-- No explanations, analysis, or additional text
-- No markdown formatting - output plain text paragraphs only
-- NO FIXED FORMAT OR TEMPLATE
+- Please output ONLY in strict JSON format: {"subject":"email subject","body":"email body content"}
+- Output must be valid JSON with proper escaping
+- No explanations, analysis, or additional text outside the JSON
+- No markdown formatting in the email content - use plain text only
+- All content must be in English
+- NO FIXED FORMAT OR TEMPLATE for the email structure
 - Make each email unique in structure and flow
 - Vary your opening and closing styles - don't fall into patterns
 - Let the conversation flow naturally without forced structure