ZMCDN

CDN to serve AI-generated images for Inform/Z-Machine text prompts

Theory of Operation

• TSZM (The Typescript Z-Machine) sends us a JSON query of the form:

zmcdnSessionID: string        // A unique UUID to identify this session (game)
lastZMachineOutput: string    // Last output from the Z-Machine
lastZMachineInput: string     // Last thing the user typed into the Z-Machine
playerLocation: string        // What TSZM thinks the players current location is (we peek inside the Z-Machine to find out)
gameIdentifier: string        // Game identified by release/serial combination (ie "59.860730" for Leather Goddesses)
illustrationFormat: string    // just 'sixel' for now, but oh boy do we have ideas for some fun targets

From here, we implement what we're calling "The Art Director Pattern":

The most recent 8 moves are sent into Qwen3-32B, along with the master prompt. Qwen, acting as Art Director, then generates a JSON prompt for the Illustrator, along with a unique name for the image and a suggestion on whether or not we need to redraw (that is, if we can re-use an old image instead of asking the Illustrator).

The Illustrator, FLUX-1-schnell, transforms the JSON input into a PNG image for us.

We convert that PNG image to Sixel format, so TSZM can dump it out to a terminal.

Building

Prerequisites

• Node.js 22
• nvm

cd zmcdn
nvm use
npm i
npm run build

Running

• Copy .env.example to .env
• Add a deepinfra.com API token to .env
• Edit the listener port in .env if needed
• Start the server:

node dist/server.js [ -i ]

Reverse Proxy

To run the server behind an apache2 httpd reverse proxy to provide a TLS endpoint or similar, you can use a Location block to rewrite the URLs so Node Express can parse them properly:

    <Location "/zmcdn/">
        Require all granted
        RewriteEngine On

        RewriteCond %{REQUEST_URI} ^/zmcdn//+
        RewriteRule ^/+(.+)$ /zmcdn/$1 [R=301,L]

        ProxyPass        "http://127.0.0.1:3000/"
        ProxyPassReverse "http://127.0.0.1:3000/"
    </Location>

Current Status

08-Oct-2025: As more focus shifts to ZMCDN, it got a much-needed refactor and documentation update.

When ZMCDN is invoked with -i, an interactive REPL lets you fiddle with things while it runs. You get commands like:

zmcdn> help
Available commands:
  trace on  - Enable trace logging
  trace off - Disable trace logging
  help      - Show this help message
  exit      - Shutdown server and exit

Public ZMCDN Server

http://zmcdn.ballmerpeak.org:3003

Credits

• @cshepherd
• @clambertus