The ChatGPT/Codex desktop app ships a full copy of LibreOffice
A look inside the app's cache folder found 1.7 GB of bundled runtimes, including full Python and Node.js installs, git, Poppler and a headless build of LibreOffice taking up almost 430 MB.
In a short note published on 1 September 2026, Simon Willison describes finding a 1.7 GB folder called codex-primary-runtime in the ~/.cache directory of his Mac while browsing disk usage with OmniDiskSweeper. The OpenAI Codex desktop app — since renamed the ChatGPT desktop app — keeps it under ~/.cache/codex-runtimes/.
What ships inside
The bundle includes a full Python installation of about 440 MB, a full Node.js installation of about 446 MB, and native binaries for git (148 MB) and for Poppler (188 MB), the library used to work with PDFs. The largest single item is a headless build of LibreOffice at roughly 430 MB, inside a native folder that totals 771 MB.
Why an office suite
LibreOffice is the free office suite that forked from OpenOffice.org in 2010. In the note, Willison points out that the plugins/openai-primary-runtime/plugins/documents folder inside the runtime holds skills that tell the app how to find and use those binaries. He does not state why OpenAI bundles them rather than relying on the tools already installed on the machine.
Where it sits in the picture
The same cache holds 356.8 GB of Hugging Face model files and 82.5 GB of uv environments on his machine, so the 1.7 GB runtime is a small share of the 442.1 GB total. Even so, it is a reminder that desktop AI apps now carry toolchains of their own.
SiTech — AI-powered web development
We build fast, modern websites and bring AI into real business workflows. Have a project or a question? We'd love to help.