My AI agent saved the first paragraph and the last. It dropped 41 in between.

Short summary

An AI agent lost 94% of content when cross-posting to Hashnode because ProseMirror's input rules silently rejected lines starting with markdown-shortcut characters. The author debugged through four incorrect hypotheses before discovering the root cause and implementing a verify-after-fill pattern with insertHTML fallback to bypass the input rules.

• •Browser automation can silently fail in rich-text editors without raising errors
• •ProseMirror input rules reject character-by-char inserts but accept bulk HTML pastes
• •Always verify editor state after fill operations and use insertHTML as a fallback

Generated with AI, which can make mistakes.