Open source · Built in public
Ask it. It draws the answer.
Work · Apps · Yui
YuiGui
An iPhone app where your agent draws the screen instead of a wall of text.
Work · Apps · Yui
YuiGui
An iPhone app where your agent draws the screen instead of a wall of text.
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Chapter 01
A timer, a form, a quick choice.
Yui answers with a small interface. You tap, and it keeps going. The screens are described in Yui Lines, a compact wire format the app renders natively.
Chapter 02
Fewer tokens per screen.
Ten screens, one tokenizer. The same screens written as a component tree, pretty JSON, minified JSON and Yui Lines.
Component tree
1,305
Pretty JSON
904
Minified JSON
530
Yui Lines
338
10 screens, o200k_base tokens, measured September 23, 2026.
Chapter 03
Built in public.
Chapter 04
Every change leaves a line.
yuigui.com is the public record. Each change to Yui adds a line to the progress log in the same commit, and a weekly update goes out every Friday.
- 01
Card
A piece of work is scoped.
- 02
Commit
The change and its progress line ship together.
- 03
Site
yuigui.com shows it.
- 04
Friday
The weekly update goes out.
Give your agent a screen.