Case study · located work
jev-ultrafast
A browser-automation runtime from Browser Use with a published performance report (docs/performance.md). The report documents a 7.07 s Google Flights run made with 17 Jev requests; that timing excludes browser setup and post-run verification, and the run finds flight results rather than booking anything.
ObservedBrowser Use (third party, not TypeSafe)
- Problem
- A browser-automation runtime from Browser Use with a published performance report (docs/performance.md). The report documents a 7.07 s Google Flights run made with 17 Jev requests; that timing excludes browser setup and post-run verification, and the run finds flight results rather than booking anything.
- Jev’s role
- Jev picks the next action and its target from a list of page controls rebuilt at every step; a small LLM is used only to fill text inputs, and the outcome is verified separately after the run reports DONE.
- Architecture
- Page → control list rebuilt each step → Jev action + target choice → small LLM for text entry only → action → DONE → separate outcome verification.
- Why it matters
- The report attributes its gains to runtime changes rather than model changes: with the same models, median browser protocol calls fell from 1,092 to 101 and median task time fell 25%. The per-run cost figure circulating with this project appears only in the author's X post, not in the report, so it is not carried here.
Code boundary
Jev answers the bounded questions described above. Thresholds, retries, side effects, and anything that must be reproducible stay in the surrounding application code. The research record does not capture this project’s exact question set or threshold values; read the linked source before copying the architecture.
Sources
Limitations
- A located repository or demonstration does not establish production reliability or independent validation.
Reusable pattern and related records
- Probabilistic predicate + deterministic action PlausibleJev supplies fuzzy predicates while TypeScript, policies, and workflows execute constrained actions.
- Support Action Gate Authored HypothesisA decision layer approving refunds, credits, escalations, and account changes within explicit limits.
- TypeSafe reports a low input-token price and no metered output-token charge for Jev. Vendor ClaimPublished pricing is echoed across launch discussion, but remains mutable vendor pricing.
- Cascade router PlausibleA cheap decision chooses whether to use rules, a small model, a premium model, a specialist, or a human.