The template talks to Telegram and stores per-chat rows in the built-in SQLite database. The copy-paste failure mode is a query that forgets chatId.

Do not open a public issue for:

• a way for chat A to read, toggle, or delete chat B's todos
• a leaked bot token or a committed .tgcloud/ directory
• a handler that trusts callback_data without checking the chat

Use a private vulnerability advisory. Do not include a token or a dump of .tgcloud/.

• Missing chatId (or equivalent) on a select, update, or delete
• Callback payloads that act on another chat's row
• Anything that would get a token or CLI credential into git
• Docs that tell someone to commit .tgcloud/ or paste a bot token into a handler

• Telegram's serverless platform, Bot API, or BotFather. Those are Telegram's.
• Enabling Serverless on a bot you do not own.
• The educational todo bot having no auth beyond "you are this chat". That is how Telegram bots work.

.tgcloud/ is gitignored for a reason. If it has been committed or pasted, revoke the bot token with BotFather and run npx tgcloud login again. Queries in lib/todos.js are the pattern: every read and write is and(eq(todos.id, id), eq(todos.chatId, chatId)) or scoped by chatId alone.