BookyAI says my blueprint file is not valid JSON, or that nothing of a book was found in it. What do I do?

"This file is not valid JSON" means the chat added text the file format does not allow, or cut the answer short. Go back to that chat and ask: "Give me only the JSON, nothing before or after it, and make sure it is complete". Save the new answer as a .json file and load it again. BookyAI (version 1.9.18 and later) already ignores a code fence and a sentence before or after the JSON, so this message means the JSON itself is broken. "Nothing of a book was found in this file" means the file has no title, no premise and no chapters that BookyAI can recognise: use "Copy the prompt" in the "Plan my book with me" card so the chat writes the file in the BookyAI format. A file over 2 MB is refused: a blueprint is a plan, not a manuscript. Long research material belongs in the book's Codex as knowledge.