Published
JevPilot is a playable driving sim that asks Jev which path to take
Justin Schroeder wired Jev into a Three.js driving simulator in under an hour, then open-sourced JevPilot the next day. The model sees compact tables of candidate paths, not pixels. Requests run up to four times a second in traffic.
On September 16, Justin Schroeder posted a clip of a Three.js car steered by Jev. He said he wired it in less than an hour. The next day he open-sourced JevPilot and put a playable build at jevpilot.standardagents.ai. The route in the README is Interstate 08: start in Millbrook, take the signed on-ramp, merge, cruise, exit into Cedar Town.
Jev does not see the frame buffer. The sim samples steering-and-speed combinations, then sends compact tables: eligible paths, road boundaries, nearby traffic, signals, stop memory, destination guidance. Shared table values go once. The road graph is sent only after the car has been more than 30 meters off course for six seconds. Detailed geometry stays local. On asphalt the sampler prefers paths that keep the whole car on the road. Off road it explores a wider field, including reverse, and supplies a recovery target. An immediate stop is offered only within 2.5 m of a blocker or stop line, at the destination, or when no moving path is eligible.
Requests run up to four times a second near turns or traffic, and about 1.5 times a second on clear roads. Questions with one eligible answer are resolved in the client. The J key toggles autopilot. The hosted /api/decide path needs a login; the API key stays on the server. Sign-in includes $0.25 of free Jev play credit. Local npm run dev skips login and bills your own key.
A later post from Schroeder put 15,000 Jev requests at $1.24, next to a week of maxed $200 Codex and Claude subscriptions. On September 18 he argued the list price is still high for control loops. At $0.042 per million input tokens, 10 Hz with 10k of context would be $0.0042 per second, about $15 per hour. He wants on-device weights, or roughly 10 times cheaper API pricing, before treating that as an industrial primitive. TypeSafe has not published an on-device Jev.
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Editorial notes evaluating claims against primary sources, contextualizing findings alongside related implementations, and defining technical terms.
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The September 16 clip and the September 17 follow-up match the repository: a Three.js simulator, Jev choosing among sampled steering-and-speed paths, hosted play at jevpilot.standardagents.ai with $0.25 of demo credit after login. The README states request rates of up to 4 per second near turns or traffic and about 1.5 per second on clear roads. Geometry and control stay in the browser. We did not drive the hosted build or measure those rates. This is a game, not Tesla Autopilot. The $1.24 for 15,000 requests and the $15/hour 10 Hz sketch are Schroeder's own arithmetic from later posts, not a TypeSafe invoice.
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Browser Use and Stagehand also keep pixels (or most of them) off the model: the host builds an action list, Jev picks, the runtime clicks. Tetris enumerates legal landings. JevPilot enumerates candidate trajectories. Watts's trader posts a buy or sell every 300 ms block; JevPilot posts a path several times a second. Schroeder's later note is the first on this desk to price a continuous 10 Hz loop at current list rates and call the result still too expensive for industrial control.
Terms
- Action table
- The compact state Jev sees: eligible paths, road boundaries, nearby traffic, signals, stop memory, and destination guidance. Shared values are sent once.
- Decision rate
- How often the sim asks Jev for a new path. The README caps this at 4 Hz in traffic and about 1.5 Hz on an empty road. Single-answer questions are resolved locally.
- Play credit
- The hosted demo signs you in through Standard Agents and gives $0.25 of Jev spend. Local development uses your own TypeSafe key and skips login.