Call Assistant — user guide

Requirements

• Apple Silicon Mac (M1 or later). Intel Macs are not supported.
• macOS 14.4 or later.
• ~2 GB free for a speech model, plus roughly 4 MB per minute recorded.
• Headphones. Not optional in practice — on open speakers your microphone re-records the other side, and you get echo and doubled transcript lines.
• An Anthropic API key, only for the AI features. Recording and transcription work fully without one.

Install

1. Download the .dmg from the releases page.
2. Open it and drag Call Assistant to Applications. Run it from Applications, not from the disk image — an app launched from a mounted image cannot update itself.
3. Launch it. It is signed and notarized by Apple, so it opens without warnings.

To check your download:

shasum -a 256 -c SHA256SUMS

First-run setup

Five steps, once.

1 · Before you start. Two things to know: recording law differs by jurisdiction and getting consent is your responsibility, and your data stays on this Mac. Accept the terms to continue. This is the only step you cannot skip.

2 · Connect to Claude. Paste an Anthropic API key. It is stored in the macOS Keychain and used only for calls you trigger.

What it costs: you pay Anthropic directly. A typical call is a few cents — live analysis uses the cheaper Haiku model, and one post-call analysis uses Sonnet. The more live toggles you leave on, the more calls it makes; all off means none at all. Every session shows a running total, and you can set a per-session cap that pauses live AI when reached.

You can skip this and add a key later in Settings.

3 · Audio. Install the Call Assistant Speaker driver — one click, one admin prompt. This is what lets the app hear the other side of a call. No Homebrew, no Audio MIDI Setup, no reboot.

Then pick your microphone. System default is the first option and usually the right one: it follows whatever your Mac is using, so switching to AirPods mid-week needs no change here.

4 · Transcription model. Choose Medium (~1.5 GB, recommended) or Small (~466 MB, faster, less accurate). Downloads resume if interrupted and can be cancelled — a cancelled download keeps what it fetched.

5 · Done.

The first time you start a session, macOS asks for microphone permission. Allow it, or the app records silence from your side.

The daily flow

Before a call. Open the last session for that project → Prepare for Next Call. You get a briefing of what is still open, which you can drop straight into the new session's context.

Starting. + New Session → name it, pick a project, add participants and any context worth knowing → Start.

Context is worth writing. It is what lets the AI say "that contradicts the figure from last month" instead of nodding along.

During. The transcript builds live, You and the other side separated. Four toggles control the live helper:

Ask AI answers questions about the call so far — "what did she say about the timeline?", "summarise what we've agreed". ⌘B bookmarks the moment. Space pauses. The menu bar shows the timer and running cost with the window hidden.

Ending. End → the full transcript goes to Claude once → you get a summary, extracted actions with owners and deadlines, and decisions. Review and edit before saving — uncheck anything wrong, fix owners, add what it missed. Then Save.

Afterwards. Sessions are searchable full-text. Play any recording back with the transcript following along; click a line to jump there. The Actions view collects every open action across every call, and that is the point of the whole thing.

Troubleshooting

The app names its problems with an EXC-… code. Find yours here.

Recording and audio

EXC-NODEV — "no capture source"

Neither the Call Assistant driver nor a loopback device is available. Go to Settings → Audio and install the driver. If it says installed but not active, quit and reopen the app — the device only exists while the app runs.

EXC-MIC-PERM — microphone denied

macOS is blocking the mic. System Settings → Privacy & Security → Microphone → enable Call Assistant. The app's dialog has a button that takes you there. If it says restricted, a device-management profile is blocking it and you cannot change it yourself.

EXC-DRIVER — driver problem

Several causes, all handled without ending your session:

• During a call: the driver was lost. Recording continues, falling back to another loopback device if you have one. Your side is unaffected.
• "System output moved off Call Assistant Speaker": you (or macOS) changed the output device mid-call, so the far side may no longer be captured. Switch back in System Settings → Sound if that was not deliberate.
• "~N seconds of the far side could not be captured": your Mac stalled long enough that audio was lost. Usually Bluetooth reconnecting. That stretch is silent; everything else is intact.
• "Your sound output is still set to Call Assistant Speaker": a crash left it parked there. Pick your real output in System Settings → Sound.

EXC-NOMULTI — a warning, not an error

Only on the older loopback setup: your output is not routed so the app can hear it. The message says which case you are in. You can start anyway — the button changes to Start Anyway.

EXC-DEV-DROP — a device disappeared

Something was unplugged. The app switches to another device and keeps recording.

EXC-SLEEP — your Mac slept

The recording pauses and resumes cleanly; the timeline closes the gap. Nothing is lost, nothing is silently padded.

Transcription

EXC-MODEL — model missing or broken

Download it in Settings → Transcription. If a download completed but will not load, the app discards the bad file so you can fetch it again.

EXC-WHISPER / "transcription catching up…"

Speech recognition is behind. The recording is never at risk — audio is written to disk first and transcription catches up. If it persists, switch to the Small model for future sessions.

EXC-REPASS — archival re-pass failed

The optional high-quality re-transcription did not complete. Your original transcript is untouched. Retry from the session view.

AI

EXC-KEY — key missing or rejected

Add or re-test it in Settings. Recording and transcription keep working without one.

EXC-API-LIVE — live AI paused

Three failures in a row, so it stopped asking. The transcript is unaffected. Usually a network problem or an Anthropic outage; it resumes next session.

EXC-BUDGET — spending cap reached

Live AI stops for the rest of this session; the transcript continues and you can still Ask AI. Raise the cap in Settings for future sessions.

EXC-API-POST — post-call analysis failed

Choose Retry, or Save without analysis to keep the transcript and re-analyse later. Nothing is lost either way.

EXC-EMPTY — too little was said to analyse. Save or discard.

Files and sessions

EXC-DISK — a write failed

Usually a full disk. If it happens mid-recording, the session is saved and closed immediately rather than pretending to continue — everything up to that point is intact.

EXC-CORRUPT — "⚠ Unreadable"

One session's file will not parse. The rest of your library is fine. Reveal in Finder to inspect it.

EXC-CRASH — recovered a session

The app closed unexpectedly and rescued the recording. Audio and transcript are written continuously, so at most the last second or so is missing.

EXC-NOAUDIO — the recording file is gone; the transcript still works.

Updates

EXC-UPDATE — cannot check right now

The app refuses to update while a session is recording, while it is finishing one, during a transcription pass, or mid-setup — installing means quitting, and quitting mid-call would cost the recording. Finish, then try again.

Updates never install by themselves. You are always asked.

Your data

Everything is in one folder:

~/Library/Application Support/CallAssistant/

Plain files: .wav recordings, .jsonl transcripts, .json metadata. Copy them, back them up, or delete them in the Finder. Export any session to Markdown from its detail view.

Nothing leaves your Mac except the Claude API calls you configure. The privacy statement lists every connection the app makes.

Privacy · Support · Terms of use are in the app under Settings → About.