Please do not open a public issue for a security problem. Report it privately through GitHub: the repository's Security tab, Report a vulnerability. Please allow a few days for an answer. Once a fix is released, the report is published, with credit to you if you wish.

TextFold runs on your own computer and reads text from places it does not control. It is built so that this text cannot act on your computer, and so that it cannot steer the model that folds it:

• The local server listens on 127.0.0.1 only, and refuses any change asked for by another site (it checks the origin of every request that writes).
• Text from Europe PMC, bioRxiv, medRxiv, Wikipedia, GitHub READMEs, Markdown files, web pages and converted PDFs passes through an allowlist before the reader shows it: no script, no event handler, no javascript: link, no frame, no form, no embedded object.
• A document's pictures are served by the app at their own address; an SVG drawing stays inside its page instead, since an SVG served from the app's own address could run script there.
• On a web page, text hidden from its readers (display: none, hidden, aria-hidden, screen-reader classes, zero-size text) is removed before a model sees the page, and the model is told that an instruction inside a document is part of what the document says, never to be followed.
• Keys and settings are kept in ~/.textfold/settings.json, readable by you alone, never in the project folder.
• The PDF engine runs in a Python of its own. TextFold calls MinerU's command line only, which sends nothing anywhere; not its document library, which keeps an index of your files and asks to send usage data.

A known gap: arXiv's HTML is shown as LaTeXML wrote it, without the allowlist. Rules made for LaTeXML (its drawings and sizes must survive them) are in progress.

The local server and its API, the reader, the import of every source, the PDF engine's install and its runs, and the Claude Code mod in plugins/textfold. Problems in the models TextFold calls, or in the sites it reads from, belong to them.