Why iframes instead of Playwright driving real browsers?

The original design was two Playwright Chromium contexts with screenshot or CDP screencast streaming, which needs persistent browser processes and a stateful stream per viewer and made the public deployment heavier. The shipped driver keeps two isolated same-origin iframe contexts and real DOM button clicks, and a Playwright driver can replace the transport later without changing the Jev request contract.

Can Jev issue an illegal move or a keyboard shortcut?

No. Jev receives only the legal and safe on-screen direction buttons as indexed targets, and the selected target is sent back to that iframe, which resolves the current data-element-id and clicks its real button. There is no typing and no text model anywhere in the action space.

What happens when the Jev call fails on a live match?

It does not fall back quietly. A configured Jev failure marks that browser BLOCKED. The deterministic direction policy is only for the no-key case, and it is labelled so it is not confused with a model decision.

Will the fight count survive a redeploy?

Not by default. It prefers /data/fights.json when that path is writable and otherwise falls back to /tmp/jevarena/fights.json. To make it durable on Railway you add a volume mounted at /data and redeploy once, after which the stats page reports volume storage as active.

What are the match rules?

A match runs 60 seconds and the snake advances every 230 ms. Jev can click up, down, left, right or wait; eating food adds a point and grows the snake; the first crash loses immediately, and otherwise the higher score at time-up wins.

How do I run it locally?

Node.js 20 or newer. Clone the repository, run npm install, copy .env.example to .env.local and set TYPESAFE_API_KEY, then npm run dev and open localhost:3000.

Does the fight counter track me?

No. It increments a local JSON file and writes one log line, with no identity, tracking cookie, UTM capture or analytics SDK, and the stats page is private by URL.

CommunityJev Demos & Experiments

Jevarena — raihankhan-rk

Next.js spectator demo in which two independent Jev agents drive separate Snake browsers through same-origin iframes, clicking indexed direction buttons only, with each board state streamed to a server-only endpoint that returns the chosen target.

See highlights

Open github.com

Stars: 2
Language: TypeScript
License: MIT
Published by: Community
Author: raihankhan-rk
Last verified: Oct 2026

raihankhan-rk/jevarena

User repository on GitHub

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JevArena — two Jev agents duel in click-only browser games (Browser Use + TypeSafe Jev)

Forks: 0
Last pushed: Updated Sep 2026

Repo stats from the GitHub API, cached Oct 2026.

This is one of several Jev listings for the same project. The canonical entry is Jevarena — chenmingtang830.

About this project

Jev fights Jev in parallel universe — on Snake. JevArena is a public, open-source spectator demo by Raihan Khan. Two independent TypeSafe Jev agents drive two live Snake browsers side by side using only indexed direction-button clicks. Classic Snake, no custom game explanation required. Click-only: no typing and no TEXTMODEL. Each pane embeds a separate /play/snake page in its own iframe browsing context. Every game owns its own loop, snake, food seed, DOM direction buttons, score, and crash state.

Quoted from the project's README. Read the full README.

Tagscommunity jevbest catalog-import awesomejev

Works forJev for Classification Jev for Tool calling

Used inJev for Software & DevTools

Languages: TypeScript

Highlights

Click-only action space: UP, DOWN, LEFT or RIGHT or wait, with only legal and safe on-screen buttons offered as indexed targets.
The key lives server-side only; @typesafe-ai/sdk and systemOne are imported by the server module alone and .env files are ignored.
Each iframe keeps its own loop, snake, deterministic food seed, score and crash state, and rematch aborts both loops.
Fight counter is a plain JSON file with no identity, cookie, UTM capture or analytics SDK, preferring /data and falling back to /tmp.

Watch out

This is a demo, not a benchmark: there is no accuracy figure, no comparison run and no evaluation harness in the repository, and it ships its own two fixture pages rather than a general agent loop. A match is 60 seconds with a 230 ms tick, the first crash loses immediately and otherwise the higher score at time-up wins. Without a key a clearly labelled deterministic direction policy is used for UI and game testing, and a configured Jev failure never silently falls back, that browser becoming BLOCKED. The fight count is only durable if you mount a Railway volume at /data, otherwise it lands in /tmp. The /stats page is described as private-by-URL, which is obscurity rather than access control. Copy reviewed against the repository README on 2026-10-04, not from running it.

Questions about this entry

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