Setup · about 5 minutes

Getting started.

Sidecar has two halves that both run on your own Mac: the browser extension you chat in, and a small companion app it talks to. You don't need a terminal for Sidecar itself.

Before you start, you'll need: an Apple-Silicon Mac (M1 or newer) on macOS 13+, Chrome or Brave, and Claude Code or Codex installed and signed in with your own subscription — that's the AI that does the answering. You only need one of the two.

Install the companion app

Open the .dmg you were given, drag Sidecar onto the Applications shortcut, then open it from your Applications folder. It lives in your menu bar — leave it running while you browse. (If your browser says the file "couldn't be scanned for viruses," that's normal for a larger download — choose Keep / Download anyway.)

Add the browser extension

Add Sidecar to Chrome or Brave. It asks to "read and change all your data on all websites" — that's what lets it read a page when you ask about it, and it reads one only while you're chatting about it, never in the background. Open the panel with the toolbar icon or ⌘⇧Y.

Install and sign in to Claude Code or Codex

Whichever you'll use — Claude Code (your Claude subscription) or Codex (your ChatGPT subscription). That's the AI doing the answering, on your own subscription. In the panel, choose which one answers in Settings → Backend, then pick the model per message from the send bar.

Look for “App connected”

When the panel's status line shows a green App connected, you're ready to ask your first question. If it says "Can't reach app," open the Sidecar app from your menu bar and give it a moment.

The top of the Sidecar panel showing a green dot with 'App connected' and the find, new-chat, and settings icons.

First launch

If macOS blocks the app.

Because Sidecar isn't from the App Store, macOS asks you to trust it once. This clears for good after the first time.

Open it once

Double-click Sidecar in Applications. You'll see a message like "Apple could not verify 'Sidecar' is free of malware." That's expected.

Allow it in Settings

Open System Settings → Privacy & Security, scroll to Security, and click Open Anyway next to the line about Sidecar. Confirm with your password or Touch ID.

Open once more

Double-click Sidecar again and click Open. macOS remembers your choice — you only do this once.

Optional add-ons

Two things you can add later.

Sidecar works fully without either. Both run entirely on your Mac once downloaded.

Transcribe videos without captions

To ask about a video that has no transcript, turn on listening, which uses Whisper. Sidecar can use a Whisper you already have, or set one up for you — see the app's settings. Off until you ask for it.

A more natural read-aloud voice

Out of the box, read-aloud uses your Mac's built-in voices. In Settings → “Read answers aloud” you can download an optional natural voice (about 65 MB, plus a one-time ~20 MB shared voice program) that then runs offline. The built-in voices stay the default.

If something's off

Quick fixes.

“Can't reach app”

The companion app isn't running. Open Sidecar from Applications or your menu bar; the panel reconnects on its own within a couple of seconds.

The shortcut does nothing

Another extension may already use ⌘⇧Y. Set your own at chrome://extensions/shortcuts under "Open the Sidecar panel."

Nothing happens on a page

Sidecar works on ordinary http/https pages, not on chrome:// pages or the extensions page.

A video won't answer

It may have no captions. Turn on Listen so Sidecar can hear it and transcribe on your Mac.

Now learn the everyday controls →