Setup

Cauchy is a native macOS app. Installing it takes one download; picking where answers come from takes one more step, and one of the five options needs nothing at all.

Requirements

macOS 27.0 (Golden Gate) or later.
An Apple Silicon Mac if you want the on-device Apple Intelligence connector.
Nothing else. There is no account to create and no license key.

Install

Download Cauchy.dmg from the latest release, open it, and drag Cauchy.app into Applications. There is no Homebrew cask yet, and Cauchy is not on the Mac App Store — see the FAQ for why.

Releases are signed ad-hoc rather than with a paid Developer ID, so the first launch shows “Apple could not verify Cauchy is free of malware”. Open it once from System Settings > Privacy & Security > Open Anyway, and macOS stops asking.

If instead you see “Cauchy is damaged and can't be opened”, you are on one of the v1.0.0–v1.0.2 builds, which shipped half-signed. Download v1.0.3 or later, or clear the quarantine flag by hand:

xattr -dr com.apple.quarantine /Applications/Cauchy.app

Build from source

Building needs Xcode 27 beta or later with the macOS 27 SDK — Command Line Tools alone cannot build the app. The full instructions, including the SwiftMath checkout and the project generator, are in the README.

git clone https://github.com/jerrydjin/cauchy.git && cd cauchy && ./scripts/run.sh

Choose an assistant

The connector picker sits next to the ask field, and Settings remembers your choice. Every option bills to you, not to Cauchy: an on-device model costs nothing, a CLI rides the subscription you already pay for, and the Gemini API uses your own key.

Apple Intelligence — nothing to set up

Turn on Apple Intelligence in System Settings and Cauchy can use the system model through Apple's Foundation Models framework. There is one model, so no model picker appears. Reference indexing prefers this connector even when you ask questions with another one.

Claude Code — your Anthropic subscription

Install Claude Code, then run claude in Terminal and log in. Cauchy detects the claude binary, spawns it per ask, and never sees your credentials. Models offered: Fable, Opus, Sonnet and Haiku.

Codex — your ChatGPT plan

Install OpenAI's Codex CLI and sign in once:

brew install codex && codex login

The picker then offers GPT-6 Astra, Sol and Luna.

Antigravity — your Google sign-in

Install Antigravity's CLI, then run agy and sign in with Google:

curl -fsSL https://antigravity.google/cli/install.sh | bash

agytakes no model argument, so Cauchy shows no model picker for it — set the model with /model inside agy and Cauchy follows it.

Gemini API — bring your own key

Create a key in Google AI Studio and paste it into Cauchy's Settings. It is stored in the macOS Keychain, never in a plist, and usage is billed to your Google account. Gemini is also the fallback that builds reference indexes on Macs without Apple Intelligence. You can also choose another available model when rebuilding an index.

Why the app is unsandboxed

Three of the five connectors work by spawning a CLI that lives in your shell. The macOS App Sandbox forbids that outright, so Cauchy ships unsandboxed and has the same access to your files as you do. That is also why it cannot be distributed through the Mac App Store.

Where files land

~/Library/Application Support/Cauchy/workspaces/<id>/ — highlights, threads, viewport state, thumbnails.
~/Library/Application Support/Cauchy/reference-index/ — cached theorem and definition indexes, rebuilt on demand.
Sidecar files written beside the PDF by older versions are migrated on open.

Still stuck?

Open an issue at github.com/jerrydjin/cauchy/issues, or read the rest of the FAQ.