JEV Tetris — thelau

The README's own three-seed run says yes and no: Jev as built survived 83, 300 and 90 pieces with 23, 115 and 23 lines; random play scored 0 lines; but a keyword table over the same sentences reached 118, 73 and 118 lines, and El-Tetris cleared 118/118/116. It plays, but the README prints a stronger baseline.

It never sees the board. Every frame, code searches every place the falling piece can be manoeuvred — tucks and spins included — and writes each as a sentence about trapped space, line clears, surface and position. Jev answers a multiple-choice question over those sentences with a probability for each, in about 380 ms.

You need Node 22 or later. Clone the repo, copy .env.example to .env and put your TYPESAFE_API_KEY in it, then run npm run dev and open http://localhost:5173. There are no dependencies and no build step; two fonts load from Google Fonts at runtime.

Yes, in mock mode: npm run dev:mock serves the whole interface on fake answers, and it plays badly. In normal mode, with no key there is no START button and the page explains why instead of failing. The engine and UI test suites also run without a key and without cost.

A game costs a few cents, per the README. The server refuses to spend past 1,500 calls or $1, whichever comes first, and the key never leaves the server. The mock mode is free because it never calls Jev.

test:engine runs 33 checks on the rules: no overlaps or floats, line clears with rows falling, blocked spawn ending the game, fair and repeatable bags, plus a 400-move audit for cell-count drift. test:ui drives the page in headless Chrome: no scrolling at five viewport sizes, panel toggling, a dropped connection stalling instead of ending the game, and START beginning a new round.

?hold=900 keeps the field on screen longer for filming, ?seed=42 fixes the piece sequence and ?auto=1 skips the start screen and restarts forever. M mutes the eight-bit sound generated in the browser, and HOW IT WORKS is the only control apart from START.