Folio Writer

Folio Helper

A small, free companion app that lets the Mac App Store edition of Folio Writer compile with the tools already installed on your Mac — the ones Apple's sandbox doesn't allow the app to launch itself.

What it's for

The App Store edition runs in Apple's sandbox, which forbids launching outside programs — including typesetting tools you've installed with Homebrew, MacTeX, or TinyTeX. Folio Helper is a tiny agent that lives outside the sandbox and runs those tools on Folio's behalf: pandoc, pandoc-crossref, typst, xelatex / pdflatex / lualatex / latexmk, tectonic, quarto, and the claude command line. With it installed, compiling to PDF via your own LaTeX, rendering .qmd projects with Quarto, and the writing assistant's Claude CLI mode all work in the App Store edition.

How to install

1. Download the zip above and unzip it (Safari may have done this already).
2. Drag Folio Helper.app into your Applications folder.
3. Open it once. It has no window — it registers itself as a background helper and appears under System Settings ▸ General ▸ Login Items as "Folio Helper".
4. In Folio Writer, open Compile ▸ Set Up External Tools… and press Re-check. The helper card lists every tool it found, with its path and version.

What it does — and doesn't

• Runs only the fixed list of tools above — it can't be asked to run anything else.
• Runs them only when Folio Writer asks; connections are verified to come from Folio by code signature.
• No window, no menu bar item, no network access of its own, nothing collected. It looks for tools in the usual places (Homebrew, MacTeX, TinyTeX, /usr/local) and via your login shell's PATH.

Uninstalling

Quit it (System Settings ▸ Login Items ▸ turn off "Folio Helper"), then delete Folio Helper.app from Applications. Folio Writer keeps working; compiling simply falls back to what the sandbox allows.