Install and First Launch
Install and launch NEXUS before continuing — the rest of this path assumes it is running.
NEXUS is cross-platform. macOS is the build available today; Linux and Windows are coming. The steps below describe download and first launch on the macOS build; everything from The workspace tour onward describes behaviour of the app itself, not this one platform's install mechanics.
Always current
Download links, system requirements and release notes live on the Chainabit Nexus product page. That page is the authoritative source — check it there rather than here for anything version-specific.
1. Download
| Platform | Link | Status |
|---|---|---|
| macOS | Download for macOS | Available |
| Linux | Download for Linux | Coming |
| Windows | Download for Windows | Coming |
Each link resolves to the current build at the moment you follow it, so it does not go stale between releases and you can bookmark it. The Linux and Windows links exist already and will begin serving builds when those platforms ship.
If a link does not resolve, open the product page — it lists whatever is published right now.
2. Install it
- Open the downloaded disk image from your Downloads folder. A window opens showing the app beside a shortcut to your Applications folder.
- Drag the app into Applications. Do this rather than running it from the mounted image: NEXUS stores your agents, workspaces and settings on disk, and running from a disk image means they go away when the image is ejected.
- Eject the disk image — drag it to the Trash, or press ⌘E in Finder. The installed copy does not need it.
- Launch NEXUS from Applications, Spotlight or Launchpad.
You will see: a short pause on first launch while macOS verifies the app's signature. This does not repeat on later launches.
3. Open NEXUS for the first time
NEXUS opens on a sign-in screen titled "Welcome to Chainabit Nexus" — you cannot use the app without one of the three paths below. You will see: a single primary button, and two smaller links beneath it for the other two paths.
4. Choose how you sign in
| Path | What you do | What it's for |
|---|---|---|
| Sign in | The primary button. Opens your browser for a normal Chainabit Cloud sign-in. NEXUS shows "Waiting for approval in your browser…" until you approve it there, with a Cancel option if it hangs. | A Chainabit Cloud account. |
| Developer token | A secondary link. Reveals a field for a personal access token; paste it and choose Connect. | Signing in without a browser round-trip. |
| License | A secondary link. Reveals a field for a local license key; paste it and choose Activate. | Running NEXUS entirely locally, against your own models or API keys — no Chainabit account required. |
You will see: once one of the three succeeds, the sign-in screen is replaced by the welcome tour below. If your account or license doesn't unlock the app, you're returned to this same screen rather than shown a dead end — try a different path, or one of the other two.
5. Work through the welcome tour
A short, three-page tour introduces what makes NEXUS different: agents that keep their own identity and memory, the Neural Map, and running any command-line agent locally. Use Continue and Back to move through it, or Skip at any point.
You will see: on the final page, a Get started button. Choosing it — or skipping — clears the welcome tour either way; Get started additionally creates one starter agent and a first note, so your workspace isn't empty the moment you arrive.
6. Follow the coach-mark tour, or skip it
Immediately after, a short in-context tour begins on its own, pointing at the controls covered by the next several pages of this path. You can follow it live, skip it, or ignore it and keep reading here — nothing on this path depends on finishing it, and you can replay it later from Settings ▸ General ▸ Restart Tour. The next page, The workspace tour, walks through the same ground at your own pace.
If something goes wrong
| Symptom | What to check |
|---|---|
| A download link does not resolve | That platform's build may not be published yet. Check the product page. |
| The app will not open on first launch | macOS is still verifying the signature. Give it a few seconds; it does not repeat. |
| Sign-in returns you to the same screen | The credential was not accepted. Try one of the other two paths in step 4. |
| A feature is greyed out with an upgrade link | It requires a paid plan. See Entitlements for which keys gate what. |
What "running" gives you
Once NEXUS is running and you're past sign-in, two things exist that later pages in this path depend on:
- A local MCP server, identifying itself as
nexus-mcp, reachable by any CLI you configure as its client. - A per-session credential file, written for each workspace session, carrying the loopback address and capability token a connecting CLI needs. See Paths for exactly where NEXUS keeps this file and with what permissions.
Neither of these depends on which CLI you plan to connect later — they are the same for every session, regardless of which agent ends up using them.
Next
Continue to The workspace tour.