cass.tools/getting-started
Install · run · update
Getting Started
# Getting Started with Cassandra
Cassandra is a terminal-based chat interface for Claude — the same AI
assistant you might have used at claude.ai, but running right inside
your terminal instead of a web browser. This guide walks you through
installing it and using it. Total time: about 90 seconds.
## What you need
- A computer running Linux — any modern distribution works
(Ubuntu, Debian, Fedora, Mint, Pop!_OS, Arch, and everything else)
- An internet connection
- A terminal application. On Ubuntu or Mint, open **Terminal** from
the applications menu. On most desktops you can also press
`Ctrl+Alt+T` to open one directly.
## Install it — one command
Copy this single line, paste it into your terminal, and press Enter:
```
curl -fsSL https://cass.tools/install | bash
```
That's it.
You'll see some messages as it works. Something like:
```
cass-tui installer
platform : linux-x86_64 (x86_64-unknown-linux-gnu)
manifest : https://cass.tools/manifest.json
version : 0.1.17
source : https://cass.tools/cass-tui-x86_64-unknown-linux-gnu
sha256 : f4eaf51e...
dest : /home/you/.local/bin/cass-tui
Installed cass-tui 0.1.17 to /home/you/.local/bin/cass-tui
```
Here's what's happening under the hood, in plain English:
1. The installer looks at your computer and figures out which kind
of Linux it is.
2. It downloads a single file (about 14 MB) from cass.tools.
3. It verifies the file with a cryptographic checksum, so you know
it's the real thing and hasn't been tampered with along the way.
4. It saves the file to `~/.local/bin/cass-tui` — inside your own
home directory. No administrator password is ever needed; nothing
gets installed system-wide.
The whole process takes about 30 seconds on a normal internet
connection.
## Running it
After install, look at the last few lines the installer printed.
One of two things will happen:
**If it says `Run 'cass-tui --help' to verify.`** — great, you can
just type `cass-tui` from anywhere:
```
cass-tui
```
**If it shows a `NOTE:` about PATH** — that means your terminal
doesn't yet know where to find Cassandra. The installer will tell
you the exact full path to use. It looks like this:
```
~/.local/bin/cass-tui
```
Type that (including the `~/.local/bin/` part), press Enter, and
Cassandra launches.
To make it work from any directory going forward, copy the
`export PATH=...` line the installer printed and paste it at the
bottom of your `~/.bashrc` file. Then open a new terminal and you
can just type `cass-tui` from anywhere.
## First run — signing in
The very first time you run Cassandra, it'll ask you to sign in to
your Claude account. It'll print a message something like:
```
No saved credentials. Starting Anthropic login...
```
...and it will either open a web browser automatically, or print a
URL for you to visit. Sign in the same way you would at claude.ai.
Once you're signed in, Cassandra saves your login so you don't have
to do this again.
## Using it
Once you're in, Cassandra shows a chat window right inside your
terminal. Type a question, press Enter, and Claude replies. The
response streams in word by word, just like the web version.
A few useful keys:
- `Ctrl+P` — opens the command palette, showing every feature and
shortcut Cassandra knows about. If you're ever lost, press this.
- `Ctrl+C` — cancels a response that's currently streaming, or
exits Cassandra entirely if pressed at an empty prompt.
- `Enter` — sends your message
- `Shift+Enter` — adds a newline inside your message (for
multi-line questions)
## Updates
You don't have to think about updating. Every time you launch
Cassandra, it quietly checks `cass.tools` for a newer version and,
if one exists, downloads and installs it in the background. The
next time you open Cassandra it's already up to date. Nothing for
you to do.
## If something goes wrong
### "curl: command not found"
Your system doesn't have `curl` installed. Install it first:
- Ubuntu / Debian / Mint: `sudo apt install curl`
- Fedora: `sudo dnf install curl`
- Arch: `sudo pacman -S curl`
Then re-run the install command from the top of this guide.
### "bash: cass-tui: command not found"
The installer put Cassandra in `~/.local/bin/` but your terminal
doesn't know to look there yet. Run it with the full path instead:
```
~/.local/bin/cass-tui
```
To fix it permanently, add this line to the end of `~/.bashrc`:
```
export PATH="$HOME/.local/bin:$PATH"
```
Then open a **new** terminal (not the current one) and type
`cass-tui`. It'll work from anywhere now.
### Cassandra prints "Build Expired. Update? [Y/n]"
This is normal. The closed-beta binaries are time-limited — they
expire after a day to make sure everyone is on the latest version.
Just press `Y` (or Enter) and Cassandra will update itself in
place and continue. You never need to re-run the install command.
### Anything else
Run `cass-tui --help` for options, or `cass-tui --version` to see
what version you're on. The license and contact info live at
https://cass.tools/license.
## Uninstalling
Cassandra lives in one place and doesn't touch anything else on
your system. To uninstall completely:
```
rm ~/.local/bin/cass-tui
rm -rf ~/.cassandra
```
The first line removes the program. The second removes your saved
login, settings, and update cache. That's the whole removal — no
system-wide cleanup, no administrator password, nothing else.
## Privacy
When Cassandra starts up, it makes one HTTP request to
`https://cass.tools/manifest.json` to check whether a newer
version is available. That's the entire telemetry surface: no
usage tracking, no analytics, no crash reports, no unique
identifier. If you want to verify this yourself, run Cassandra
with `--no-update` and watch the network; you'll see zero traffic
to cass.tools.
Everything you type into Cassandra goes straight to Anthropic's
Claude API, the same way it would from claude.ai. For how
Anthropic handles that data, see their privacy policy at
anthropic.com.
---
**Supported platforms today:** Linux (x86_64), any modern distro,
any libc version. macOS and Windows support are on the way.
**Closed beta:** we're still early. Please expect occasional rough
edges, and tell Jake if you hit any. That's how the beta gets
better.