Getting started

Sonocles is a menu bar app. It has no window and no Dock icon; it lives under a small mark in the menu bar and opens as a popover. The moment it launches, two sockets come up on loopback — 7357 for HTTP and server-sent events, 7358 for WebSocket — and stay up until it quits. Listening is a separate thing that you, or anything with the token, switch on.

Install

brew install --cask artisan-build/tap/sonocles

Or the disk image: sonocles.com/download always points at the current release. The app and the disk image are Developer ID signed and notarized, so Gatekeeper opens it without a right-click.

Requirements. Apple Silicon, macOS 14 Sonoma or later. The floor is Sonoma because that is what Parakeet on Core ML needs, and Apple Silicon because the models run on the Neural Engine and nowhere else — the cask refuses an Intel Mac rather than letting the failure arrive as a crash.

The first launch

Click the mark and press Start listening. The first time, two things happen before anything is heard.

macOS asks for the microphone. Sonocles asks at the first start, not at launch, and before it does anything else — it refuses to report listening until the grant exists. If the prompt is refused it falls back to idle and says so. It never claims to be listening while hearing nothing, because an earlier build did exactly that and it was the worst bug this project has had.

The models download. About 219 MB from Hugging Face, then compiled for the Neural Engine, which is tens of seconds of a progress bar and then a pulse. It is once: the models cache in ~/Library/Application Support/FluidAudio (about 428 MB compiled) and every later launch skips this entirely. Downloading has a fraction; compiling does not, and the popover does not invent one.

Then the level meter moves, and about 180 ms after you say a word, it is on the socket.

The token

Every request, on both sockets, needs a bearer token. You do not have to go and get it. The app writes it to

~/Library/Application Support/Sonocles/token

with mode 0600 the first time the sockets come up, so any app running as you can read the file and is paired with zero clicks. Anything that cannot read a file — a page in a browser, which is what Pteroprompter is — gets the same token from the popover — the Key under Connected apps, with a Copy button — and pastes it once.

TOKEN="$(cat ~/Library/Application\ Support/Sonocles/token)"
curl -s -H "Authorization: Bearer $TOKEN" http://127.0.0.1:7357/

{ "name": "Sonocles", "version": "0.1.3", "auth": "bearer",
  "ports": { "http": 7357, "ws": 7358 } }

The whole scheme is on Authentication, including why a token on loopback is not overkill.

The first frame, from a shell

Attach to the stream first, then start capture from a second terminal, and say something.

TOKEN="$(cat ~/Library/Application\ Support/Sonocles/token)"
curl -sN "http://127.0.0.1:7357/events?access_token=$TOKEN"

curl -s -H "Authorization: Bearer $TOKEN" -X POST http://127.0.0.1:7357/start

: connected
data: {"type":"partial","text":"the","ts":1788569799612,"seq":1,"audioStart":40.28,"audioEnd":40.44,"lagMs":120}
data: {"type":"partial","text":"the menu","ts":1788569799791,"seq":2,"audioStart":40.28,"audioEnd":40.62,"lagMs":180}
data: {"type":"partial","text":"the menu bar","ts":1788569800003,"seq":3,"audioStart":40.28,"audioEnd":40.8,"lagMs":200}

-N matters: without it curl buffers, and a stream that arrives in one lump thirty seconds late looks exactly like a broken one. The Makefile in the repository has make events, make start, make stop and make status, which read the token file for you.

Or the CLI

The same service, in a terminal, with a trace: sonocles-cli is the instrument every latency figure on this site came out of. It is not in the cask; build it from the repository with make run. It inherits its terminal’s microphone grant, which is worth knowing when a signed app hears nothing and the CLI hears everything.

[  9.320s] part   +294ms  Δ +1  lag   +200ms audio    4.24–   8.00  …spoke without pausing so that we can watch

Each arrival with the gap since the last one, the words it added, and how far behind the live audio edge it was. make baseline runs the same trace on Apple’s engine, so the comparison on Engines can be re-run rather than believed.