Simon Edwardsson's 360M WorldTUI Fakes a Terminal Without a Shell
Summary
Simon Edwardsson demonstrates WorldTUI, a 360M-parameter model that simulates a terminal with no shell or filesystem, predicting screen updates from each keypress. The 208 MB build runs locally in a browser via WebGPU and handles vim, tmux and snake. Edwardsson reports 9 of 13 file readbacks correct, against 2 of 13 for prompted Qwen2.5-Coder-0.5B.
Key Points
- Edwardsson trains on 336,000 recorded terminal sessions, roughly 2 billion tokens, spending about 75 GPU-hours on one RTX 4090.
- Parallel row decoding with speculative verification cuts large-frame p95 latency on an RTX 4090 from 6.7 seconds to 0.87 seconds, Edwardsson reports.
- The model uses a 333-token vocabulary and grammar-constrained decoding, so every prediction is a valid screen update.