Cassini

Cassini is a Mac app that records your meetings, writes them down, and lets you read and search them on this computer.

The Library with sample meetings. The small auto tag next to a name comes from the sample data: recognising saved voices is not available yet.

What you can do

• Record a meeting with your microphone and all of this Mac's sound (the others) together, straight into your Library, while taking time-pinned notes.
• Let Cassini write your meeting down automatically on this computer, offline, using the speech model included in the app.
• Read a meeting's transcript while listening back, with words highlighted as they are played and any word clickable to play from that moment.
• Search every meeting in your Library for a phrase, narrow matches by speaker, date, or meetings recorded by you, and jump straight to that moment.
• Open Cassini .opus files you receive from others so a copy stays in your Library as a Received meeting.
• Export any meeting to share or archive as a portable Cassini .opus audio file or as a Markdown transcript with notes.
• Record meetings in Chrome, Chromium, Microsoft Edge, or Brave using the bundled browser extension, keeping each person in the call apart.
• Preview any Cassini .opus meeting file in Finder by pressing Space for Quick Look.

Get started

Install

The latest published release, v0.1.0, is an earlier version: the Library, Recording page, writing down, Search every meeting, Received meetings, and Export described here come with the next release. Until then, you can build Cassini from source by following CONTRIBUTING.md.

Cassini requires macOS 15 or later and runs on both Apple Silicon and Intel Macs.

1. Download Cassini-<version>.zip from the Releases page (or bookmark the latest release) and unzip it. While this repository is private, downloading requires a GitHub account with access to it.
2. Move Cassini.app to /Applications. If you also want to record meetings in your browser, keep the unzipped Cassini folder (BrowserExtension and Install Browser Host.command) in a permanent folder on your Mac.
3. These early builds are ad-hoc signed and not notarized yet, so macOS 15 blocks the first launch. The old right-click → Open shortcut no longer works on macOS 15; open the app like this the first time:
   1. Double-click Cassini.app. macOS shows a dialog titled “Cassini” Not Opened saying Apple could not verify it is free of malware. Click Done, not Move to Trash.
   2. Right away, open System Settings → Privacy & Security, scroll to the Security section, and click Open Anyway next to the Cassini notice. If the notice has disappeared, double-click Cassini.app again and look again.
   3. Confirm the prompt with your administrator password or Touch ID. On company-managed Macs the button may be hidden by policy, so ask IT to allow the app.

Do this only for a build you downloaded from this repository. See Apple’s instructions for more detail.

To update later, quit Cassini, download and unzip the newer release, replace Cassini.app in /Applications, and repeat the Open Anyway step once for the new build. Updating leaves your meetings in Music/Cassini untouched.

Your first meeting

The Library before your first meeting.

Click Record in the Library (or press ⌘R anywhere in Cassini). Cassini records your microphone and all of this Mac's sound (the others) together, straight into your Library (Music/Cassini). There is no folder to choose and no save dialog.

The first time you record, a Before your first recording sheet reminds you that you are responsible for telling the people you record, and explains what will be recorded; tick Don't show again to hide it next time. macOS then asks for Microphone access, followed by Screen & System Audio Recording access so Cassini can record the others. You can review both permissions in System Settings → Privacy & Security.

The Recording page with a sample meeting. "Change what is recorded" is shown disabled and is not available yet.

The Recording page shows a large timer, live sound levels for your microphone and the others, an editable Title, and Notes where each note line is pinned to the moment you start typing it. If your microphone has been silent for 20 seconds, a warning appears with a Check button that opens your Sound settings.

Recording keeps going if you go back to the Library. If you close the window, Cassini asks whether to Stop and keep it or Keep recording in the background. Your Mac does not go to sleep while recording. While a recording is running, a timer in the menu bar offers Stop Recording, Add a Note…, and Open Cassini. You can also press ⌥⌘R (Option-Command-R) to start or stop recording from any app.

Click Stop in the Library header, on the Recording page, or in the menu-bar timer when the meeting finishes. The Library shows the meeting saving and then being written down. If you quit Cassini while recording, it asks first and saves the meeting before it closes. If disk space runs low, Cassini warns you; if it gets too low, it stops recording and keeps everything recorded so far.

Read and search your meetings

A meeting page with a sample meeting. Speaker labels such as "Named by you", "Recognised from saved voices", and the small auto tag come from the sample data and are not features yet.

When a recording stops, Cassini writes it down automatically on this Mac, offline, using the included Whistle speech model, on both Apple silicon and Intel Macs. The Library shows progress and an estimate of the time left. If you quit Cassini, it picks up where it left off next time; if writing down fails, click Try again. Received meetings without a transcript have a Write it down button.

In a meeting recorded from your microphone and your Mac's sound, words are attributed to Me and The others. In browser recordings, each person in the call is kept apart as Speaker 1, Speaker 2, and so on.

In the Library, meetings are grouped by day with a quote, the speakers, and a short transcript preview. You can start playback straight from the preview, or open the meeting to see each speaker's share of the conversation and read the full transcript. As the meeting plays, words are highlighted. Click any word to play from that moment, use the player bar to skip 10 seconds back or forward, or press Space to play and pause. The 1× button changes the playback speed, and ⌘[ takes you back to the Library. In Finder, you can also press Space on a Cassini .opus file to preview it with Quick Look.

Search every meeting with sample meetings. Filtering by speaker uses speaker names already stored in a meeting; naming speakers and the auto tag shown in the sample are not features yet.

Press ⌘F or use the search bar in the Library to Search every meeting for a phrase. You can narrow results by speaker (when a meeting has named speakers), by date (Today, Past 7 days, or Past 30 days), and with Recorded by me. Each hit shows the words around it; click Play from to listen from that moment, or Open the meeting here to open the meeting at that point. Filters reset when you close Search. The search index is private, kept in Cassini's cache folder, and never written into your Library.

Open meetings you receive

A sample meeting in the Library marked as Received.

Use File → Open… (⌘O), choose Open With → Cassini in Finder, or drop a Cassini .opus file onto Cassini to copy it into your Library as a Received meeting. The original file is left untouched, and the copy stays in your Library even if the original moves. Opening the same file a second time opens the existing copy instead of creating a duplicate.

Export a meeting

The Export sheet over a sample meeting. The note about recognised speakers comes from sample data; recognising voices is not a feature yet.

Click Export… in the meeting header (or press ⇧⌘E) to export a meeting. You have two choices:

• Cassini file — audio with the transcript, speakers, and notes inside, which plays in any audio player.
• Markdown — the transcript as text with speakers and times, plus your notes.

Cassini saves the file to Documents unless you click Choose… to pick another folder, and it never overwrites an existing file. Export is the only way a meeting leaves this computer. Voiceprints are never exported.

Record meetings in your browser

If your meeting runs in Chrome, Chromium, Microsoft Edge, or Brave, you can use the browser companion included in the release zip. It is set up per user for your own browser profiles (~/Library/Application Support/...), never system-wide, and does not need Xcode, Python, or developer tools. A meeting page in Cassini may also show a Set up suggestion, which displays these setup instructions.

1. Make sure you have opened your browser at least once, and keep the unzipped BrowserExtension folder in a permanent place on your Mac.
2. Open chrome://extensions in your browser, turn on Developer mode, click Load unpacked, and select the BrowserExtension folder. Copy the 32-letter extension ID shown on the card.
3. Double-click Install Browser Host.command in the unzipped release folder, paste the 32-letter extension ID, and press Return. (If you moved Cassini.app somewhere other than /Applications or the release folder, rerun the installer after putting Cassini.app in /Applications.)
4. Reload your meeting tab, click the Cassini Recorder extension in your browser toolbar, and start recording either with your microphone and the others kept separate, or by capturing what the whole tab plays. In browser recordings, each person in the call is kept apart as Speaker 1, Speaker 2, and so on.
5. Click Stop and save when the meeting finishes. The meeting appears in your Library in Music/Cassini and is written down automatically.

To remove the browser companion registration later while keeping your meetings:

"/path/to/Install Browser Host.command" --uninstall

If you are working from a git checkout instead of a release zip, you can register the companion with scripts/install-browser-host.sh YOUR_EXTENSION_ID (and remove it with scripts/install-browser-host.sh --uninstall). See Distribution/README.txt and docs/browser-recording-protocol.md for more detail.

Your meetings stay on this computer

Your Library lives in Music/Cassini inside your home folder (~/Music/Cassini), with one folder per meeting.

Nothing is uploaded anywhere. Cassini has no account, no sign-in, and no cloud service. Recording, writing down, and search all happen on this Mac, and writing down works offline with the included speech model. Export is the only way a meeting leaves this computer, and only when you choose. Portable meetings are ordinary .opus audio files carrying their transcript, speakers, and notes, playable in any Opus-capable player.

What's coming

• Naming speakers and keeping names for future meetings, plus recognising saved voices automatically.
• Telling apart several people who share one microphone or one sound source.
• Seeing browser meetings in the Cassini window and recording them with one click, or automatically.
• Choosing what is recorded before you start, for example recording your microphone only.

Help and feedback

If something does not work or you have a question, open an issue on GitHub Issues. Please mention your macOS version and what you were doing when the problem happened.

For developers

Instructions for building from source, running the test and conformance suites, working with the shared browser protocol, and packaging releases are in CONTRIBUTING.md. Design notes and milestone write-ups live in docs/.

License

Cassini for Mac is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License, version 3 or later.

Cassini bundles the Whistle speech model and the Needle 3.3.0 inference engine by Cactus Compute under the Apache License, Version 2.0; see Whistle/LICENSE and Whistle/NOTICE. The format conformance test vectors in Tests/CassiniKitTests/Conformance are dedicated to the public domain under CC0.