Frequently Asked Questions

A native macOS app for reading PDFs that argue with you. Open a paper, highlight a line or drag a box around a figure, and ask about it; the answer appears in a thread pinned to that spot, with mathematics typeset properly. It is built for dense technical textbooks, mathematics papers and problem sets, not for contracts or slide decks.

• Highlights that carry a conversation, saved with the document and named by the model after the first answer.
• Hover previews for cited results — theorems, lemmas, propositions, corollaries, definitions, examples and numbered equations get indexed, so “by Theorem 2.1” shows its statement without a page jump.
• Retrieval that reaches the rest of the document: BM25 keyword search plus on-device sentence embeddings supply passages from other pages.
• On-device OCR for equations the PDF stores as artwork, converted back to LaTeX before the question is sent.
• Reading essentials: continuous / single-page / two-up layouts, thumbnails, table of contents, contact sheet, ⌘F find, and a dashboard of recent documents.

Five connectors: Apple Intelligence on-device, Claude Code, Codex and Antigravity through their CLIs, and the Gemini API with your own key. The setup guide covers each one.

The app is free. Apple Intelligence costs nothing to run. The CLI connectors bill against the Anthropic, OpenAI or Google plan you already have, and the Gemini API bills your own key. Cauchy has no server, no account and no subscription of its own.

Locally, and only locally. Workspaces — highlights, threads, viewport state and thumbnails — live in ~/Library/Application Support/Cauchy/workspaces/, and cached reference indexes in ~/Library/Application Support/Cauchy/reference-index/. A Gemini API key, if you add one, is kept in the macOS Keychain.

The file itself is never uploaded. With a cloud connector, what leaves your Mac is the question, the highlighted passage and the text around it, plus the statements and passages retrieval pulled from elsewhere in the document — subject to that provider's own terms. With Apple Intelligence, nothing leaves the machine.

Cauchy itself collects no telemetry and no analytics. See the privacy policy.

With the Apple Intelligence connector, yes — reading, highlighting, OCR, retrieval and reference indexing all run on-device. The CLI and Gemini connectors need a network.

The Claude Code, Codex and Antigravity connectors work by spawning CLIs installed in your shell, which the macOS App Sandbox forbids. Running unsandboxed means the app has the same access to your files as your user account does, and that it cannot be shipped through the Mac App Store.

“Apple could not verify…” is expected: releases are signed ad-hoc, not with a paid Developer ID. Open the app once from System Settings > Privacy & Security > Open Anyway.

“Cauchy is damaged and can't be opened” means you have a v1.0.0–v1.0.2 build, which shipped half-signed and is blocked outright. Get a newer release or run xattr -dr com.apple.quarantine /Applications/Cauchy.app.

macOS 27.0 (Golden Gate) and later. Earlier versions are not supported: the app is built against the macOS 27 SDK and uses frameworks that do not exist before it.

Yes, under the MIT license, at github.com/jerrydjin/cauchy. Building needs Xcode 27 beta or later with the macOS 27 SDK; the README has the steps, including the local SwiftMath checkout that renders the mathematics.

Neither, for now. Installation is the .dmg from the latest release, and Cauchy is macOS-only.