ClaudeST

A native GEM client for claude.ai on the Atari ST, STE, Mega ST/STE, TT and Falcon, through a Raspberry Pi bridge.

Highlights

• Like the website: chats, Search, Code, Projects and Artifacts on the left, the open conversation on the right, and replies streaming in as Claude writes them.
• Your real claude.ai account: recent and pinned chats, projects, search.
• Claude Code sessions: read them and reply.
• Artifacts: view them and save them to disk, Word documents included.
• Attach files of any kind to a message, as on the website: from the file selector or dropped on the window.
• Model and effort for each chat, from a chip in the title bar.
• Right-click menus to pin, rename, move to a project, archive and delete.
• Usage at a glance: a ring that fills as you use up the current session, and an Account page with your plan and usage.
• Hebrew: right-to-left text and a Hebrew keyboard layout.
• Fonts: a font selector (Options ▸ Font…), as in EMail and ECal: the system font in two sizes, or any fixed-width GDOS font with NVDI.
• Any screen from 640×200, monochrome or colour.

The user guide describes every feature.

ClaudeST has two parts: the bridge, on a Raspberry Pi or any Linux computer on your network, and the program on the Atari. Set up the Pi first.

Give the Pi a fixed IP address, for example with a DHCP reservation in your router, so that ClaudeST always finds it. Give the Atari one too, unless you let the bridge accept any address on your network (--atari any, below). The examples below use 192.168.1.10 for the Pi and 192.168.1.20 for the Atari. Replace them with your own.

1. Log in to claude.ai in a desktop browser.
2. Open the developer tools (F12). Go to Application (Chrome) or Storage (Firefox), then Cookies, then https://claude.ai.
3. Copy the value of the sessionKey cookie. It starts with sk-ant-sid.

The key gives full access to your account. It is stored only on the Pi, readable only by root and the bridge.

The Pi side of all the AERA apps is installed by AERA-Gateway. It always installs the bridge from ClaudeST's latest release, never unreleased code (its README's Getting started has the details). In your home folder on the Pi:

sudo apt install -y git      # Raspberry Pi OS Lite only: it comes without git
git clone https://github.com/whomper/AERA-Gateway.git
cd AERA-Gateway
./update-pi.sh
sudo gateway/aera-gateway install claude --network --atari 192.168.1.20

Put the Atari's address in place of 192.168.1.20. The installer asks for the session key. It then runs the bridge as a service called claude-st, which starts at every boot and accepts connections only from the Atari's address. Use --atari IP1,IP2 for several Ataris, or --atari any to accept any address on your network. If the ufw firewall is on, the installer opens port 2323 for them.

Or the short way, which sets up every AERA gateway on the Pi in one line, ClaudeST's bridge among them (over the network, for the Atari's address):

sudo apt install -y git && git clone https://github.com/whomper/AERA-Gateway ~/AERA-Gateway && ~/AERA-Gateway/update-pi.sh --allow 192.168.1.20

It also installs the gateways of ECal and EContact, EFTP and EWeb, which do nothing until those apps use them; for the bridge alone, use the steps above. update-pi.sh makes aera-gateway a command, so from then on sudo aera-gateway works in any folder.

The latest release has these files, each on its own and all together in CLAUDEST-x.y.zip (the icon files in its icons/ folder):

1. Load STinG and check that the network works, for example by pinging the Pi.
2. Copy CLAUDEST.PRG, CLAUDEST.HYP and CLAUDEST.REF into one folder, any folder on any drive.
3. Run CLAUDEST.PRG, choose Options ▸ Settings… (Ctrl+,), pick Network and type the Pi's address (port 2323). Or type /connect 192.168.1.10 in the reply line. The status line at the bottom left shows Connecting…, then Online, with a green dot.

ClaudeST keeps what you set in CLAUDEST.INF, which it writes next to the program. If the Pi restarts or the network drops, ClaudeST reconnects by itself. The guide's Icons section says how to put the icon on the desktop.

• The Atari: from a new release, copy CLAUDEST.PRG, CLAUDEST.HYP and CLAUDEST.REF over the old ones. Your settings, in CLAUDEST.INF, stay as they are.
• The Pi: when a release's notes say the bridge changed, run cd ~/AERA-Gateway && ./update-pi.sh (see Looking after the Pi). It is safe to run at any time. gateway/aera-gateway status in the same folder shows what runs and which ClaudeST release.

Connect the Atari's Modem port to a USB-to-RS-232 adapter on the Pi with a null-modem cable. Don't wire the Atari straight to the Pi's GPIO pins: the Atari's ±12 V signals damage the Pi. Then, on the Pi:

sudo gateway/aera-gateway install claude --serial auto

On the Atari, choose Options ▸ Settings… and pick Serial (a new ClaudeST, with nothing set yet, starts on the serial port). Both sides use 19200 baud by default. The guide's Serial cables and ports says which port to use on each Atari.

Run the installer again with --backend api (or add it in step 2):

sudo gateway/aera-gateway install claude --backend api

The installer asks for an API key. Chats are then stored on the Pi, in /var/lib/claude-st/chats/, instead of in your claude.ai account. --backend demo gives sample chats without any account, to test the setup.

Needs: an ST, STE, Mega ST/STE, TT or Falcon with TOS 1.04 or newer, EmuTOS or MiNT; a 640×200 or larger screen; about 370 KB of free RAM (ClaudeST makes do with 260 KB, keeping less of a long chat); STinG with a working network, or a null-modem serial cable; a Raspberry Pi, or any Linux computer, on the same network; a claude.ai account, or an Anthropic API key.

Under TOS, put Atari's FOLDR100.PRG first in AUTO, renamed for more room (FOLDR400.PRG). TOS keeps an entry in a small internal pool for every folder a program or accessory has looked into, and halts with "OUT OF INTERNAL MEMORY" when it runs out; FOLDRxxx makes the pool bigger.

With STinG, set the Delay in STING.CPX to suit the machine: 10 on a Falcon or TT, 25 to 50 on an ST, as STinG's manual says. STinG looks at the network card that often, so it sets the speed of every STinG program: on a Falcon with a NetUSBee, Delay 10 took EFTP's downloads from 40 to 75 KB/s.

An 8 MHz 68000 can't do modern HTTPS, so a small Python program, the bridge, does it for the Atari. It runs on a Raspberry Pi or any Linux computer on your network:

STinG:   Atari (CLAUDEST.PRG) --plain TCP, home LAN, port 2323--> Raspberry Pi (bridge) --HTTPS--> claude.ai
Serial:  Atari (CLAUDEST.PRG) --null-modem cable, 19200 baud----> Raspberry Pi (bridge) --HTTPS--> claude.ai

• Through STinG, over Ethernet or WiFi, the Atari connects to the bridge's port 2323. The bridge accepts only the addresses you gave the installer with --atari.
• Through a serial cable, the Atari's Modem port goes to a USB-to-RS-232 adapter on the Pi.
• The bridge talks to claude.ai (or the Anthropic API) and sends the Atari short lines of text in the Atari character set. The Atari does all the drawing and word wrapping itself.

The bridge is in bridge/, its installer and service in pi/. To run it without the installer, on macOS or Windows too, see the guide's The bridge on another computer.

Run these in the AERA-Gateway folder:

update-pi.sh brings AERA-Gateway to its latest release and the bridge to ClaudeST's latest release, keeping every setting. The same installer sets up EMail's, ECal's and EFTP's gateways on the same Pi. The settings are in /etc/claude-st/claude-st.env. If claude.ai can't be reached or the session key has expired, the error appears on the Atari.

A Pi set up earlier with ClaudeST's pi/install.sh is taken over as it is: clone AERA-Gateway and run ./update-pi.sh. pi/install.sh still works, and now also installs the bridge from the latest release.

The guide has all the keys.

ClaudeST is an unofficial client, not affiliated with Anthropic or Atari. claude.ai has no public API for personal accounts, so the bridge uses the same private interface as the claude.ai website. If claude.ai changes it, parts can stop working until the bridge is updated. The guide's Troubleshooting section has commands that check each part from the Pi.

With claude.ai, your chats stay on claude.ai: the bridge fetches them each time and doesn't store them. The Pi keeps only your session key, the bridge's settings and the effort you chose for each chat. The guide lists what is stored where.

ClaudeST was first called Claude ST, then EClaude for a few days. To upgrade, replace CLAUDE.PRG or ECLAUDE.PRG with CLAUDEST.PRG: your settings in CLAUDE.INF or ECLAUDE.INF are read the first time, then saved as CLAUDEST.INF. The Raspberry Pi side keeps its service name, claude-st.

ClaudeST was written with Claude, in Claude Code on claude.ai: a claude.ai client for the Atari, built by talking to claude.ai.

sudo apt install gcc-m68k-linux-gnu python3 zip   # Debian/Ubuntu; no MiNTLib needed
make                         # binary/CLAUDEST.PRG
make test                    # the bridge's tests and the right-to-left layout's, on this computer
make help HCP=/path/to/hcp   # binary/CLAUDEST.HYP and .REF (common/tools/build-hcp.sh DIR builds hcp)
make dist                    # dist/CLAUDEST-x.y.zip and each file, as on the Releases page

binary/ and dist/ are what make builds; they are never committed, and a build changes no tracked file. The version is VERSION in st/claudest.c: the last release, which every build shows in the About box. A release: tools/bump.py, commit and push, then Actions > Release > Run workflow on main with what is new. The workflow tests, builds, tags the commit vX.Y and publishes each file and the zip on the Releases page. Pushing a tag vX.Y made with git tag -a does the same, with the tag's message as the notes.

The guide's Building section has more: the shared code, other toolchains, running ClaudeST in Hatari, recording the demo video and retaking the screenshots.

st/        the Atari program: claudest.c (UI and protocol), bidi_test.c
help/      CLAUDEST.STG, the ST-Guide help (make help)
bridge/    claude_bridge.py (links and protocol), backends.py (claude.ai, API, demo),
           atari_text.py (charset and Markdown), test_bridge.py
pi/        install.sh (hands on to gateway/aera-gateway) and the systemd service
gateway/   the AERA gateways for the Pi and aera-gateway, their installer, which sets up the
           bridge: a copy of AERA-Gateway's (tools/sync-gateway.sh)
common/    the AERA programs' shared code, a git subtree of AERA-Atari: start-up, C library,
           TOS, AES/VDI, STinG, the right-to-left layout, elf2tos.py
tools/     hatari-test.sh, sync-common.sh, sync-gateway.sh, bump.py, check_version.sh,
           docshots.py (the screenshots), icon/ (the desktop icon), reel/ (the demo video)
tests/     hatari/: disk_budget.sh (the disk-access check), font_gdos.py (a GDOS font) and
           long_field.sh (a name longer than its box)
icons/     the desktop icon files (make icons, from common/icons/CLAUDEST.txt)
docs/      the user guide (GUIDE.md), its screenshots, the demo recording and the help's front
           page (front.json, help/WINDOW.IMG: help/Makefile adds it with common/tools/helpfront.py)

The program is freestanding C with its own start-up code and AES, VDI and STinG bindings, so it needs no MiNTLib and no resource file. Change common/ in AERA-Atari, never here, then bring the copy up to date with tools/sync-common.sh. PROTOCOL.md describes the line protocol between the Atari and the bridge.

make test runs, on this computer:

• the bridge's tests (bridge/test_bridge.py): the Atari character set, Markdown, and the protocol against the demo backend and stubbed claude.ai answers, with no account or network needed;
• the right-to-left layout's test (st/bidi_test.c, with common/src/bidi.c).

The CI workflow runs them, and builds the program, on every push to main and every pull request.

To try ClaudeST itself, tools/hatari-test.sh boots Hatari into it, with EmuTOS 1.4 (downloaded the first time, or your own TOS images in ~/.aera/tos) and the bridge on this computer, connected through the emulated serial port:

tools/hatari-test.sh                 # demo chats, no account needed
CLAUDE_SESSION_KEY='sk-ant-sid01-...' tools/hatari-test.sh claudeai
MACHINE=Falcon tools/hatari-test.sh  # ST (the default), ST-1, TT or Falcon; ST:med for colour
LINK=network tools/hatari-test.sh    # over STinG instead of the serial cable

Hatari has no network card: with LINK=network, the shared FAKESTNG.PRG (common/tools/fakesting, built by the script) stands in for STinG by tunnelling its TCP connections over the serial port to the bridge on TCP port 2323, as on the Pi, to test the network code. It is for the emulator only; never install it on a real Atari. The guide's Running it in Hatari has more.

tests/hatari/disk_budget.sh checks ClaudeST's disk work in Hatari against the AERA rule (the guidelines, 6.5), from Hatari's GEMDOS trace. It fails if a conversation or an idle window touches the disk at all, or if saving a 50 KB artifact or attaching a 40 KB file takes more than one open and a few big reads or writes (MACHINE=ST-1 or TT for the other machines).

tests/hatari/font_gdos.py WORK chooses the first fixed-width GDOS font in Options ▸ Font and checks that the window redraws in it with no dialog left, that CLAUDEST.INF keeps it, and that a Hebrew chat draws the same after a restart. It needs GDOS fonts (NVDI: AERA_WITH_NVDI=1 on the Falcons, see common/tools/machines.py) and skips without them; --release v1.49 tests a release.

tests/hatari/long_field.sh types a 62-character name into Rename, whose box shows 43, going to the start and the end of it with Shift+← and Shift+→, and checks that the bridge gets all of it (the guidelines, 5.4; MACHINE= as above).

ClaudeST (the Atari program, the bridge and the Pi's setup) is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version. It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See COPYING.

Copyright (C) 2026 AERA | Erez Yaary.

ClaudeST is an unofficial client, not affiliated with Anthropic or Atari; Claude is a trademark of Anthropic PBC, Atari a trademark of Atari Interactive.

The shared common/ folder also carries, for the other AERA programs, BearSSL by Thomas Pornin (MIT licence) and Mozilla's root certificates (Mozilla Public License 2.0); ClaudeST doesn't use them.

Part of AERA for Atari: ECal · EContact · EMail · EFTP · EHypView · ClaudeST · EWeb · EUpdate · 8-bit: EDOS · EFTP_XL · Pi: AERA-Gateway