A Claude chat client for the Commodore 64.
Type a message on the C64, get a streaming response from Claude — over a real (emulated) RS-232 serial connection.
C64 (VICE) proxy (Python) Anthropic API
────────────── ────────────── ─────────────
claude64.prg ←─ IP232 ─→ claude_proxy.py ←─ HTTPS ─→ claude-haiku
Swiftlink drv TCP 127.0.0.1:25232
The C64 side is a ~200-byte-per-turn chat UI written in C and compiled with cc65. The proxy handles IP232 framing, conversation history, and streaming the Anthropic Messages API back to the C64 one character at a time.
Requirements
| Tool | Purpose |
|---|---|
cc65 (cl65) |
Cross-compiler for the C64 |
VICE (x64sc) |
C64 emulator |
| Python 3.9+ | Proxy server |
| Anthropic API key | ANTHROPIC_API_KEY env var |
Build
make
Produces c64/build/claude64.prg and copies the Swiftlink driver to
c64/build/c64-swlink.ser.
Run
export ANTHROPIC_API_KEY=sk-ant-...
./scripts/run.shThis starts the proxy and launches VICE in one step. The C64 loads the Swiftlink driver from device 8, connects, and shows the chat prompt.
Usage
Type a message and press Return to send. The response streams in as it arrives. Press RUN/STOP to cancel the current input line. Press F1 to clear the screen.
Built-in debug commands:
| Command | What it does |
|---|---|
/rx |
Send the current line and hex-dump the raw bytes received |
/raw |
Same but print printable ASCII instead of hex |
/local |
Enter offline echo mode (no API calls); /exit to leave |
Echo mode (no API key needed)
./scripts/run.sh --echo
Echoes input back without calling Anthropic. Useful for testing the serial link and UI without spending tokens.
License
MIT — see LICENSE.