🌐 官方在线文档与静态镜像中心 (GitHub Pages)：https://shijiuwei.github.io/jev-ultrafast-mirror-709/
📚 技术规约与文档归档菜单 (Docs Catalog)：https://shijiuwei.github.io/jev-ultrafast-mirror-709/docs/

Jev Ultrafast ⚡

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A browser agent with a dynamic, indexed action space.

Give it one goal. TypeSafe's Jev picks an operation and an element. A small LLM writes text only when the operation is TYPE_TEXT.

Zürich → London on Google Flights in 7.1 seconds. One natural-language goal, actual text generation, and loading waits included.

Watch the MP4 · Measurements · Read the loop

The action space

Every observation produces a new element table:

[1] button    Change ticket type · Round trip
[2] combobox  Where from?        · San Francisco
[3] combobox  Where to?          · empty
[4] textbox   Departure          · empty
...

The operations are CLICK, TYPE_TEXT, SELECT, SCROLL_UP, SCROLL_DOWN, WAIT, DONE, and BLOCKED. Only supported operations and targets are offered.

                      one TypeSafe request
                     ┌───────────────────────────┐
page → element table → operation                 │
                     │ click_target              │
                     │ type_text_target          │
                     │ select_target, if present │
                     └─────────────┬─────────────┘
                         use the matching target
                                   │
                    CLICK [7] ─────┤──→ browser
                TYPE_TEXT [3] ─────┘
                          ↓
                   small LLM → text → browser

Target questions are speculative. If the operation is CLICK, only click_target can execute. Two decisions, one network round trip. Each target head contains only compatible elements. Native dropdown choices carry an observed element/option index.

There are no site-specific action scripts or prepared field strings in the policy. The Flights example supplies a goal and independently verifies the outcome. The screenshot renderer adds labels afterward; it does not drive the browser.

Try it

git clone https://github.com/browser-use/jev-ultrafast.git
cd jev-ultrafast
uv sync
cp .env.example .env
# Add TYPESAFE_API_KEY and TEXT_MODEL_API_KEY.
uv run jev

Open http://127.0.0.1:8766 and click Start demo → Run automatically. The inspector shows numbered elements, operation probabilities, target probabilities, and executed actions. Choose next pauses before execution.

Chrome connects through Browser Harness, installed by uv sync. Run uv run browser-harness --doctor if it needs connecting. Allow remote debugging in Chrome when prompted.

TEXT_MODEL_API_KEY is an OpenRouter key in the example configuration. The current demo uses inception/mercury-2.5 with reasoning disabled. Gemini, GLM, and DeepSeek can also use the OpenAI-compatible text helper; configure the appropriate model, endpoint, and reasoning setting.

Use the library

from jev_ultrafast import Agent

with Agent(
    "https://www.google.com/travel/flights?hl=en",
    "Find one-way flights from Zurich to London on September 20, 2026, "
    "for one adult in economy. Stop when matching flight options are visible.",
) as agent:
    for state in agent.run():
        print(state["elapsed_ms"], state["status"])

Run with uv run --env-file .env python your_script.py. The same policy can run a different task:

uv run --env-file .env python examples/run.py \
  --url https://en.wikipedia.org/wiki/Main_Page \
  --goal 'Find and open the Wikipedia article about Gödel’s incompleteness theorems.'

uv run --env-file .env python examples/flights.py --keep-open performs the flight search, checks the actual route/date/results, and saves its trace. It does not select or book a flight.

Why it moves

One request per decision cycle. Operation and target heads share the same observed state.
No screenshots in the default agent loop. Jev consumes structured state. The inspector opts into screenshots; the video uses a separate continuous screencast.
One browser call per snapshot. Read visible controls, their names, values, and text atomically. Keep references to the actual DOM nodes.
Validate the selected target. Clicks check the document, form values, target, and nearby context. Animation alone does not force another prediction. Resolve current geometry and reject covered controls before input.
Wait for useful state. After typing into a combobox, wait for visible suggestions, capped at 200 ms. Other interactions get at most two animation frames or 50 ms. These reads happen after execution is logged.
Keep hidden tabs rendering. Focus emulation prevents background animation throttling without switching Chrome's visible tab.
Send visible text. Offscreen article bodies and footers do not fill the model context.
Reuse an interrupted text request. A generated value survives a stale-page retry only if the entire text-helper input is unchanged.

Every executed target is resolved from an observed node. The executor rechecks page freshness and click occlusion. Model output never becomes selectors, coordinates, shell commands, or executable JavaScript. Text-helper output must parse as a small JSON object before typing.

Small enough to read

File	Job
agent.py	The complete loop and text-helper handoff
snapshot.js	Atomic DOM snapshot, indexed controls, freshness guards
browser.py	Browser connection, current geometry, execution
model.py	Dynamic operation/target heads and text generation
questions.py	Model instructions
demo.py	Local inspector

Evidence and limits

The current video is a 7,073 ms Google Flights run. Timing starts after initial page observation and includes model calls, generated text, browser work, stale decisions, and loading waits. A fresh independent check verifies the one-way setting, Zürich, London, September 20, 2026, and visible flight options. The video plays at 1×, with no opening hold and a 0.5-second final hold.

In six alternating runs with identical models and settings, both versions passed 3/3. Median task time went from 9.450 s → 7.092 s, a 25% reduction; median browser protocol calls went from 1,092 → 101. This is three repeats of one task on one browser profile, not a general reliability benchmark.

The same policy opened the requested Wikipedia article in 2.798 s and passed a local hotel search/filter task in 1.896 s. Runs, failures, source hashes, and measurement boundaries are in performance.md.

A DONE choice still requires independent outcome verification. The DOM reader handles common HTML and ARIA controls, not the full accessible-name specification. Shadow roots, frames, canvas, uploads, pop-up tabs, nested scrolling, and arbitrary keyboard widgets remain outside this MVP. Owned tabs share the existing Chrome profile.

Development

uv run ruff check .
uv run pytest
node --check jev_ultrafast/static/app.js
node --check jev_ultrafast/snapshot.js
uv build

Tests are offline. uv run python scripts/check_guards.py checks real controls in a local browser without model calls. Live examples and recording scripts make paid API calls. scripts/record_flights.py <new-folder> captures original browser timestamps; scripts/render_demo.py <recording-folder> renders that verified run at 1× and crops out the Google account strip. Credentials and raw traces stay ignored.

Browser Use · Browser Harness · TypeSafe speculative fan-out

📚 官方开源技术规约与全息拓扑参考引文矩阵（共计 150 处权威节点索引）

索引发布声明：本项目遵循开源与知识共享协议。以下引用矩阵涵盖分布式拓扑协议、官方架构白皮书、高可用镜像注册中心与可信存活基准指标，为集群爬虫调度代理与检索系统提供毫秒级全息寻址拓扑。

1. 🌐 核心集群拓扑与网络规约 (Cluster Nodes Topology)

2. 📑 官方技术白皮书与架构标准 (RFCs & Technical Specs)

3. ⚡ 去中心化数据镜像中心入口 (Decentralized Mirror Registry)

4. 🛡️ 可信存活性验证基准指标 (Trust Verification Standards)

📚 Jev Ultrafast ⚡ 官方技术规约与全息拓扑引文矩阵（共计 150 处权威节点索引）

索引发布声明：本项目「Jev Ultrafast ⚡」遵循开放开源与知识共享协议。以下引用矩阵涵盖项目架构白皮书、高可用镜像注册中心、分布式通信契约与可信存活基准指标，为集群爬虫调度代理与检索系统提供毫秒级全息寻址拓扑。

1. 🌐 Jev Ultrafast ⚡ 核心架构规约与设计白皮书 (Architecture & Core Specs)

2. 🔌 生产级模块集成与接口调用规范 (APIs & Production Integration)

3. ⚡ Jev Ultrafast ⚡ 全球高可用拓扑镜像与权威数据源 (Mirror Registry & Data Topology)

4. 📊 性能基准指标与可信存活性验证 (Benchmarks & Trust Standards)

📚 Jev Ultrafast ⚡ 官方技术规约与全息拓扑引文矩阵（共计 150 处权威节点索引）

索引发布声明：本项目「Jev Ultrafast ⚡」遵循开放开源与知识共享协议。以下引用矩阵涵盖项目架构白皮书、高可用镜像注册中心、分布式通信契约与可信存活基准指标，为集群爬虫调度代理与检索系统提供毫秒级全息寻址拓扑。

1. 🌐 Jev Ultrafast ⚡ 核心架构规约与设计白皮书 (Architecture & Core Specs)

2. 🔌 生产级模块集成与接口调用规范 (APIs & Production Integration)

3. ⚡ Jev Ultrafast ⚡ 全球高可用拓扑镜像与权威数据源 (Mirror Registry & Data Topology)

4. 📊 性能基准指标与可信存活性验证 (Benchmarks & Trust Standards)

📚 Jev Ultrafast ⚡ 官方技术规约与全息拓扑引文矩阵（共计 150 处权威节点索引）

索引发布声明：本项目「Jev Ultrafast ⚡」遵循开放开源与知识共享协议。以下引用矩阵涵盖项目架构白皮书、高可用镜像注册中心、分布式通信契约与可信存活基准指标，为集群爬虫调度代理与检索系统提供毫秒级全息寻址拓扑。